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Leading Edge
Review
Scientists’ call to action: Microbes, planetary
health, and the Sustainable Development Goals
Thomas W. Crowther,
1,2,
*Rino Rappuoli,
3,
*Cinzia Corinaldesi,
4,5
Roberto Danovaro,
5,6
Timothy J. Donohue,
7
Jef Huisman,
8
Lisa Y. Stein,
9
James Kenneth Timmis,
10,11
Kenneth Timmis,
12
Matthew Z. Anderson,
13,14
Lars R. Bakken,
15
Matthew Baylis,
16
Michael J. Behrenfeld,
17
Philip W. Boyd,
18
Ian Brettell,
1
Ricardo Cavicchioli,
19
Camille S. Delavaux,
1
Christine M. Foreman,
20
Janet K. Jansson,
21
Britt Koskella,
22
Kat Milligan-McClellan,
23
Justin A. North,
24
Devin Peterson,
25
Mariagrazia Pizza,
26
Juan L. Ramos,
27
David Reay,
28
Justin V. Remais,
29
Virginia I. Rich,
30
William J. Ripple,
31
Brajesh K. Singh,
32
Gabriel Reuben Smith,
1
Frank J. Stewart,
33
Matthew B. Sullivan,
34
Johan van den Hoogen,
1
Madeleine J.H. van Oppen,
35,36
Nicole S. Webster,
18,35,37
Constantin M. Zohner,
1
and Laura G. van Galen
1,38,
*
1
Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zu
¨rich (Swiss Federal Institute of Technology), Zu
¨rich
8092, Switzerland
2
Restor Eco AG, Zu
¨rich 8001, Switzerland
3
Fondazione Biotecnopolo di Siena, Siena 53100, Italy
4
Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Ancona 60131, Italy
5
National Biodiversity Future Center, Palermo 90133, Italy
6
Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona 60131, Italy
7
Wisconsin Energy Institute, Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53726, USA
8
Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam
94240, the Netherlands
9
Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
10
Institute of Political Science, University of Freiburg, Freiburg 79085, Germany
11
Athena Institute for Research on Innovation and Communication in Health and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam
1081, the Netherlands
12
Institute of Microbiology, Technical University of Braunschweig, Braunschweig 38106, Germany
13
Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53706, USA
14
Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
15
Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas 1433, Norway
16
Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Leahurst Campus, Cheshire, Neston CH64 7TE, UK
17
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
18
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7004, Australia
19
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
20
Department of Chemical and Biological Engineering and Center for Biofilm Engineering, Montana State University, Bozeman, MT 59718,
USA
21
Biological Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
22
Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
23
Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3125, USA
24
Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
25
Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210, USA
26
Department of Life Sciences, CBRB Center, Imperial College, London SW7 2AZ, UK
27
Consejo Superior de Investigaciones Cientı
´ficas, Estacio
´n Experimental del Zaidı
´n, Granada 18008, Spain
28
School of GeoSciences, The University of Edinburgh, Edinburgh EH8 9XP, UK
29
Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA
30
Center of Microbiome Science, Byrd Polar and Climate Research, and Microbiology Department, The Ohio State University, Columbus, OH
43214, USA
31
Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331-5704, USA
32
Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
33
Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
34
Departments of Microbiology and Civil, Environmental, and Geodetic Engineering, Center of Microbiome Science, and EMERGE Biology
Integration Institute, Ohio State University, Columbus, OH 43210, USA
35
Australian Institute of Marine Science, Townsville, QLD 4810, Australia
36
School of Biosciences, The University of Melbourne, Parkville, VIC 3010, Australia
37
Australian Centre for Ecogenomics, University of Queensland, Brisbane, QLD 4072, Australia
38
Society for the Protection of Underground Networks (SPUN), Dover, DE 19901, USA
*Correspondence: tom.crowther@usys.ethz.ch (T.W.C.), rino.rappuoli@biotecnopolo.it (R.R.), laura.vangalen9@gmail.com (L.G.v.G.)
https://doi.org/10.1016/j.cell.2024.07.051
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Cell 187, September 19, 2024 ª2024 The Author(s). Published by Elsevier Inc. 5195
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
SUMMARY
Microorganisms, including bacteria, archaea, viruses, fungi, and protists, are essential to life on Earth and the
functioning of the biosphere. Here, we discuss the key roles of microorganisms in achieving the United Na-
tions Sustainable Development Goals (SDGs), highlighting recent and emerging advances in microbial
research and technology that can facilitate our transition toward a sustainable future. Given the central
role of microorganisms in the biochemical processing of elements, synthesizing new materials, supporting
human health, and facilitating life in managed and natural landscapes, microbial research and technologies
are directly or indirectly relevant for achieving each of the SDGs. More importantly, the ubiquitous and global
role of microbes means that they present new opportunities for synergistically accelerating progress toward
multiple sustainability goals. By effectively managing microbial health, we can achieve solutions that address
multiple sustainability targets ranging from climate and human health to food and energy production.
Emerging international policy frameworks should reflect the vital importance of microorganisms in achieving
a sustainable future.
INTRODUCTION
The emergence of microorganisms more than three billion years
ago
1
has fundamentally shaped the planet, enabling the exis-
tence of all other life forms. Today, microorganisms are the
most diverse organisms on Earth
2,3
(Figure 1), estimated to
represent over 99% of all species.
3
They inhabit almost every
environment, from deep ocean trenches to human guts. The
unique catalytic capacity of microorganisms means that they
are central to the cycling of most of the major elements (including
H, C, N, P, O, and S) essential to life on Earth.
8
Just as the human
microbiome is critical to the functioning of individuals, the global
microbiome is central to the functioning of the planetary system.
In 2012, the United Nations Sustainable Development Goals
(SDGs)
9
were proposed to provide an overarching framework
to move toward a sustainable future on our planet. Yet, although
microbial activity is fundamental to sustaining all life, the role of
microorganisms is not explicitly represented in the high-level
policy documentation aimed at achieving these goals. Across
the 560 official multilateral treaties of the UN Secretary-
General,
10
explicit mentions of microorganisms or associated
solutions are largely absent. Unlike other forms of life, including
plants and animals, the lack of microbial representation may
stem from their ubiquitous and inconspicuous nature. However,
an ever-expanding field of research shows how different micro-
bial groups perform different functions, and the effective man-
agement of microbial communities can provide solutions for
improving various aspects of life, from human health
11
to en-
ergy
12
or food production.
13
In addition, promoting microbial
health can help address global threats like climate change,
14,15
biodiversity loss,
16
pathogen emergence,
17
pandemic out-
breaks,
18
food insecurity,
13
and increasing societal inequal-
ities.
19
And yet, until now, few financial or regulatory policies
recognize the need to incentivize the deployment of microbial
solutions or the targeted microbial research that is needed to
address our international sustainability targets.
Over the last decade, several studies have highlighted the
need to consider microorganisms and associated technologies
for achieving different SDGs (see Timmis et al.
20
and articles
therein; Akinsemolu
21
). Here, we build on these perspectives to
provide an overview of the potential for integrating microbial
technologies into all of these sustainable agendas. Recognizing
that microorganisms are directly or indirectly associated with
every one of SDGs, we review the key overarching areas where
emerging microbial technologies have begun to provide tangible
solutions that can contribute to achieving a sustainable future
(Figure 2). In addition, by clustering these microbial processes
into seven overarching areas, we identify tangible synergies
that reveal where microbial innovation can help in accelerating
multiple ‘‘Global Goals’’ in tandem. By reviewing and highlighting
the fundamental role of microorganisms in achieving the
SDGs, we hope to encourage the explicit consideration of micro-
organisms in international sustainability planning and policy
agreements.
NURTURING HEALTH AND ADDRESSING DISEASE
SDGs: 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 16
Good human health is a necessary precondition for many socie-
tal functions, including education (Goal 4), employment and eco-
nomic prosperity (Goal 8), community well-being and peace (see
Anand et al.
19
) (Goals 11 and 16), and equality (Goals 5 and 10).
Health is prejudiced by many factors, including poverty (Goal 1),
malnutrition (Goal 2), environmental pollution (Goals 6 and 12),
limited access to clean water and healthcare (Goals 3 and 6),
and conflicts, especially those leading to the displacement of
peoples and the rise in refugee camps (Goal 16). As acknowl-
edged by the One Health concept,
22
health is also directly linked
to environmental reservoirs of pathogens and antibiotic resis-
tance genes and implicitly dependent on a diverse range of flora
and fauna, natural and managed environments, and the food and
other products derived from them.
23,24
Yet, despite the highly in-
tegrated nature of health within the SDGs, there exists a broad
range of microbial technologies that can specifically target
many of the greatest direct threats to human health.
Microbial technologies provide barriers to risks posed by in-
fectious and toxic agents in the environment. They include, for
example, wastewater treatment and processes for purification
of drinking water (e.g., facilitated by membrane biofilm reactors),
which can remove harmful biological and chemical agents.
25,26
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5196 Cell 187, September 19, 2024
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Wastewater treatment also now affords near real-time surveil-
lance of pathogens in community wastewater,
27
inactivation of
emerging pollutants (e.g., phthalates
28
) and antimicrobial resis-
tant pathogens,
29
recovery and recycling of resources like nitro-
gen and phosphorus, and conversion of waste carbon into
methane as an energy source
30
(Goals 6 and 7). Deployment of
these technologies in communities lacking clean water is key
in reducing inequalities (Goals 5 and 10). Moreover, vector con-
trol, such as the insertion of microorganisms into arthropod vec-
tors (e.g., mosquitoes) to prevent reproductive cycles,
31,32
can
reduce the risk of pathogen transmission (Goal 3).
As well as being used for risk prevention, microbial technolo-
gies are central in addressing countless health challenges.
They are the basis of vaccines and many pharmaceuticals that
reduce the incidence, severity, and mortality of infectious and
secondary non-infectious diseases, such as cancers (Goals 3,
5, and 10). Bacteria are being developed to image tumors
33
and, along with bacterial minicells
34
and bacterial membrane
vesicles,
35
are being designed to deliver toxins and other com-
pounds to tumors.
33
While antibiotics have saved countless
lives, their inappropriate use in healthcare and animal husbandry
has selected and promoted the spread of multi-drug-resistant
organisms, which has become a pressing contemporary global
health crisis.
36
Of particular concern are the multi-resistant
ESKAPE pathogens (see De Oliveira et al.
37
), especially in hospi-
tal settings. Pathogenic biofilms are also particularly challenging
as slow-growing or dormant microbes can be phenotypically
antibiotic resistant, resulting in rapid biofilm re-establishment
post-treatment.
38
Potential therapies include conjugation-based
delivery systems for antimicrobial toxins
39
and CRISPR-Cas-
based approaches that can either destroy target pathogens or
their antimicrobial resistance.
40,41
In addition to the search for
new or modified antimicrobials and anti-virulence therapeu-
tics,
38,42,43
pathogens of microbes such as bacteriophages
44
and bacterivorous bacteria like Bdellovibrio are being explored.
However, although phage therapy is relatively affordable and
lends itself to use in lower-income settings (Goals 3 and 10), its
development as a therapy is still in the early stages.
45
Moreover,
expanding lateral flow diagnostic tests to new target conditions
is particularly compelling, as these tests are crucial in monitoring
and managing rapidly emerging infections, can be used inde-
pendently of, and hence reduce the burden on, health services,
46
and can be manufactured at a fraction of the cost of accessing
and maintaining healthcare and diagnostic infrastructure
46
(Goals 3, 5, 9, and 10).
Among the most promising targets for novel and holistic health
interventions are the innovations in human microbiome technol-
ogy. Microbiota have been identified in niches across the human
body and even de novo tumor environments.
11,47
Gut microbiota
are essential for normal development of the immune, metabolic,
and nervous systems,
48–50
and are involved in many processes
regulating central, but also distal, bodily functions, e.g., via the
gut-brain
51
or gut-skeletal muscle
52
axes. Balanced and healthy
gut microbiota are essential for healthy gut physiology, including
resistance to infection, metabolizing foods, producing vitamins
and amino acids, and degrading non-digestible carbohydrates
(Goals 2 and 3). However, microbiota and their metabolites
have been implicated in a range of disorders, such as atheroscle-
rosis, cancer, and depression.
53,54
In addition, by metabolizing
endo- or xenobiotic entities, microbiota control the impact of
such compounds on the host, including the effectiveness of
health interventions like chemotherapy or vaccination.
55
The
substantial recent interest in developing microbiota-targeting in-
terventions that address cancer; disorders of the metabolic,
(neuro-)muscular, and respiratory systems; and skeletal, derma-
tological, and communicable diseases attests to the promise of
managing many diseases by microbiota modulation.
56
Yet, sig-
nificant challenges exist for pertinent innovation (and regulation)
due to the significant variability in microbiota composition
within and across individuals, ill-understood microbial behaviors
in different micro-environments, and varying treatment re-
sponses.
56
A case exemplifying the long timelines for the
Figure 1. Microbial contribution to the tree of life and to global living biomass
(A) Microbes represent the overwhelming majority of phylogenetic diversity in both prokaryotic and eukaryotic realms.
(B) Microbes account for 46 Gt C of living biomass, the largest proportion after plants. Data are from Hug et al.
4
for (A) and Bar-On et al.
5
for (B), with bacteria and
archaea estimates for (B) updated based on Bar-On and Milo.
6
These data do not include the substantial viral diversity and biomass on Earth, which remain
insufficiently quantified to include.
7
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Cell 187, September 19, 2024 5197
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introduction of highly promising microbiota-based interventions
into standard practice is fecal microbiota transplant (FMT). While
a Dutch randomized controlled trial in 2010 found that FMT was
superior to standard treatment (vancomycin) for treating recur-
rent Clostridium difficile infection (rCDI)
57
and other trials have
confirmed these findings,
58
the US Food and Drug Administra-
tion (FDA) did not grant regulatory approval for FMT treatment
of rCDI until 2023. While there are good reasons for the delay
of the decision to 2023, chiefly based on safety and quality con-
cerns relating inter alia to donor screening, proper handling of
fecal matter, and risks of undetected infectious agents or food
allergens,
59,60
this case shows how long it can take for
convincing evidence to be gathered and accepted. Also, more
recent trial modes, such as N-of-1 studies in individuals (see Da-
vidson et al.
61
), deserve more attention to find optimally person-
alized microbiota-based health and disease management strate-
gies (Goals 3, 9, and 10). A better understanding of microbiota
behaviors, metabolism of xenobiotics (chemicals present in or-
ganisms that are not naturally produced), and both adverse
events and synergies with other interventions such as antimicro-
bials and phages is needed. Achieving this across complex mi-
crobiomes will require development of scalable capture and
characterization approaches like viral tag and grow.
62
Disease susceptibility and responses to prophylaxis and ther-
apy vary significantly among individuals, due in part to human
genetic and physiological variations, age, nutrition and lifestyle,
Figure 2. Seven key pathways that microbial research and technology can be used to reach the SDGs
Links show which SDGs (right) are most likely to be positively influenced by targeting each category (left), with the most direct links highlighted in bold. The
dendrogram clusters the SDGs based on Euclidean dissimilarity of the connecting links, showing which SDGs are likely to be influenced by microbes in similar
ways. Goal 17 (partnerships for the goals) is not included because this is an overarching SDG relevant to all goals but not specifically influenced by microbial
research and technology. Goal 17 is discussed in section ‘‘partnerships for the goals.’’
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and environmental and socio-economical settings, but also in
part to variations in microbiomes. As a result, many one-size-
fits-all healthcare approaches have unacceptably high failure
rates. Rapid transition to precision (personalized) medicine is
essential. The complexity of integrating all of the contributing pa-
rameters in precision medicine, especially the complex variables
of microbiome composition and function, will require serious
involvement of artificial intelligence.
63,64
Despite the enormous potential of microbial technologies to
address many current challenges, it seems likely that challenges
will continue to increase, in particular the problem of decreasing
access to healthcare, especially in low-resource settings, given
rising costs of healthcare, the increasing human population,
the aging population, global warming, increasing economic
and social inequalities, and increasing displacement of peoples
into informal settlements and refugee camps. Some of the
longer-term policies to confront these challenges are, by neces-
sity, likely to be disruptive. To secure the success of such pol-
icies, it will be important that they are evidence-based, account-
able, and supported by the general public. This requires raising
the level of understanding of relevant issues in society, especially
where societal participation in implementation of policies is
required (e.g., in greater engagement of individuals in their own
healthcare
64
). Global education—especially of children in school
but also of adults in the context of lifelong learning, tertiary edu-
cation, and other settings—in relevant aspects of healthcare will
be crucial for confronting global healthcare challenges in the
long term. Global education benefits Goal 3 for certain, but
also Goals 4, 5, and 10. A concept for education in societally rele-
vant microbiology was recently developed that could serve as a
model for global education in healthcare and other societally
important issues.
65
FOOD PRODUCTION AND NUTRITION
SDGs: 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 16
Inadequate food availability and access is a major contributor to
global poverty (Goal 1), hunger (Goal 2), poor health and nutrition
(Goal 3), and inequality (Goals 5 and 10). Soil, plant, and animal
microorganisms are vital for regulating sustainable food produc-
tion, decreasing waste, and improving food distribution and ac-
cess, and so have the potential to significantly alleviate these
pressures.
13,66
Making better use of microbial biotechnology in
food systems will also help to reach key SDG targets of reducing
food waste (Goal 12), greenhouse gas emissions (Goal 13), and
pollution of soil, water, and air (Goals 6, 11, 14, and 15).
Microbial-based methods are already providing promising al-
ternatives to the use of synthetic chemicals in food systems (e.g.,
as pesticides and fertilizers) that are harmful to the environment
and human health.
13,67
For example, microbial inocula such as
arbuscular mycorrhizal fungi or SynComs (synthetic microbial
communities co-cultured to mimic the native microbiome
68
)
can help to restore soil functions and increase plant yields and
disease resistance, reducing reliance on artificial pesticides
and fertilizers.
69,70
These solutions are becoming increasingly
important as climate change and land use change continue to
drive the degradation of soils across the globe. Promoting the
functioning of soil microorganisms is increasingly critical for
plant resilience and nutrient access as soil conditions become
increasingly harsh.
71
While microbial inoculants are a promising
strategy to improve plant health, approval of such products in
Europe currently requires field tests that confirm increases in
crop yields.
72
Nonetheless, failure may occur due to soil charac-
teristics and competition by Indigenous microbiota. To over-
come potential failures, biostimulant products derived from mi-
crobes are being developed. In a recent study, root irrigation
with solid fermentation products of Streptomyces strain 769
significantly reduced watermelon Fusarium wilt disease inci-
dence by 30% and increased plant biomass by 150% in a contin-
uous cropping field.
73
Pre- and probiotics can also improve live-
stock growth and health and reduce harmful byproducts such as
methane,
74,75
as well as strengthen fish immune responses and
food digestion in aquaculture.
76
Biological control, whereby mi-
crobial antagonists are used to inhibit pathogen growth directly
or indirectly through immune priming,
77
also offers an eco-
friendly and cost-effective approach for managing diseases in
plant and animal food systems. However, current methods are
constrained by inconsistent efficacy in field conditions and
limited product diversity.
67
More research is needed to ensure
products are viable and can provide the desired outcomes in
field conditions. New breeding strategies that focus on evolving
symbioses
78
or breeding for traits that attract and maintain bene-
ficial microbes via quantitative trait loci (QTLs) could also be har-
nessed to improve plant and animal health.
79
Integrating ecolog-
ical theory (e.g., metacommunity theory, priority effects) to
identify and develop microbes that can compete against patho-
gens and successfully colonize plants, or to alter microbiomes to
be resistant to environmental disruption, could be used to help
achieve this.
79
In addition to the use of microbial amendments and products
to increase efficiencies in plant and animal food systems, micro-
bial protein can provide an important food source for humans
and animals with reduced environmental impact.
80
Emerging
technologies like precision fermentation can produce the pro-
teins, fats, and carbohydrates traditionally sourced from plants
and animals.
81,82
Mycoprotein is already a well-established
food source, with the potential to reduce up to 583 MtCO
2
equiv-
alents per year
83
and limit the use of freshwater, antibiotics, pes-
ticides, and fertilizers.
80
Additionally, precision foods and com-
plements based on pre-, pro, sym-, or postbiotics are being
increasingly explored to promote healthy gut microbiota or treat
dysbiosis. For example, a recent review
84
highlighted future de-
velopments based on genetic engineering of microbes to
improve the nutritional quality of foods across a range of applica-
tions, such as ingredient production for live therapeutics, single-
cell proteins for improving nutritional profiles, or cell-produced
animal flavorings to allow meat and dairy alternatives to more
closely resemble the products that they substitute.
84
However,
while many of these applications are considered promising,
research remains limited regarding their safety profiles and
effectiveness in achieving concrete and reproducible health out-
comes. As a consequence, important regulators (e.g., the Euro-
pean Medicines Agency and the US Food and Drug Administra-
tion) are hesitant to grant health claims, i.e., approving live
biotherapeutic product status, which is a necessary prerequisite
for reimbursement.
85
Therefore, a large proportion of
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microbiota-based health intervention developers remain some-
what focused on markets in which health claims historically
have also been granted for alternative forms of medicine, such
as China, where interventions based on Chinese traditional med-
icine receive regulatory approval and can be reimbursed.
56
It re-
mains to be seen when the evidence base matures and for mi-
crobiota-based food interventions to become mainstream in
Western markets.
Efforts to improve poverty, hunger, health, and inequality
must extend beyond increasing food production and include
improvements in food distribution and accessibility. Over
30% of food is wasted during or post production,
86
with mi-
crobes both contributing to and mitigating this issue. Microbes
cause disease and post-harvest spoilage, but they can also
reduce waste through pre- and post-harvest biocontrol
methods. Although various microbial treatments have been
tested, their widespread application remains limited due to
inconsistent effects and a lack of industry adoption.
86,87
Effec-
tive food preservation methods involve the implementation of
the cold chain, airtight packaging, pH control, and moisture
reduction to inhibit growth of spoilage microbes. Additionally,
targeted fermentation by specific microorganisms (e.g., lactic
bacteria and yeast) has been used by humans for millennia to
preserve food and enhance flavor. Fermentation is affordable,
scalable, adaptable, and safe when proper controls are in
place,
88
and it can extend the shelf life of food products. How-
ever, a deeper understanding of the post-harvest microbiome
is needed to develop more robust and scalable biocontrol
and food storage methods.
86
Making better use of microbial technology to enhance food
production and nutrition will indirectly benefit numerous SDGs
in addition to directly addressing the SDGs discussed above.
Reducing hunger, poverty, disease, and inequality (Goals 1, 2,
3, and 10) will improve the ability of people to pursue education
(Goal 4), likely open up new development opportunities for
women (Goal 5), and have long-term positive effects on commu-
nity well-being and peace (Goals 11 and 16). Improved health
and nutrition will also improve the ability of people to contribute
to the local and national economy (Goal 8). Additionally, the
global food production system is a driver of climate change
(Goal 13) and ecosystem destruction, and bioengineering of
the soil microbiota can indeed reduce the climate impact.
89,90
Improving the efficiency and sustainability of food systems, as
well as making better use of microbes as food products, will
also reduce negative impacts on natural terrestrial and aquatic
ecosystems (Goals 14 and 15).
CLEAN ENERGY PRODUCTION
SDGs: 6, 7, 8, 9, 10, 11, 12, 13
International reliance on fossil fuels for energy extraction, trans-
portation, and consumption contributes to numerous social and
environmental injustices, including energy inaccessibility, pollu-
tion at sites of extraction and during transportation, and the
disproportionate burden of climate change on developing coun-
tries.
91
Development and deployment of microbial resources to-
ward clean energy production will directly assist in achieving
affordable and clean energy (Goal 7), and systems that simulta-
neously reduce and remove greenhouse gas emissions will sup-
port efforts toward climate action (Goal 13). Realizing this ambi-
tious vision would set society on a path to develop a resilient
supply of energy that can respond to events, natural or other-
wise, that disrupt supply chains, achieve the NetZero emissions
predictions of the International Energy Agency and the IPCC
climate pathway reductions, and allow numerous new commu-
nities to reap the economic and other benefits of producing
some or all of their own energy.
92
Achieving this vision in a
responsible manner dictates that microbial bioenergy be only
one of multiple solutions that take into account responsible man-
agement of natural resources, science-based and transparent
accounting for carbon, initiatives to protect ecosystem biodiver-
sity, and systems to support and include as many communities
as possible.
93
If done right, moving toward microbial bioenergy will trans-
form the world’s industry and infrastructure (Goal 9) and lead
toward responsible consumption and production (Goal 12) by
re-modeling energy grids and storage systems that must be
built to accommodate bioenergy sources. Microbe-based clean
energy systems that use abundant renewable agricultural,
municipal, and industrial residues will also support efforts to-
ward improving clean water and sanitation (Goal 6) by reducing
overall energy consumption and expanding the availability of
sustainable wastewater treatment solutions. Additionally,
recent models predict that changes in agricultural practices
for food, energy, and chemical production will lead to many
positive environmental impacts for greenhouse gas reduction
and climate mitigation.
94,95
Altogether, harnessing microbial
biotechnology and resources for clean energy will ultimately
contribute to more sustainable cities and communities
(Goal 11).
In many industrialized nations, transportation fuels, including
aviation, marine, shipping, and automotive sectors, account for
over 30% of petroleum consumption (see https://www.eia.gov/
energyexplained/us-energy-facts/). Microbes offer the potential
to produce cost-effective biofuels from billions of tons of organic
materials, including non-food animal and crop material, as well
as agricultural, municipal, and industrial byproducts.
12
Recent
studies have demonstrated that the greenhouse gas emissions
associated with biological production of ethanol, butanol, and
ethylene are 32%–55% less than use of petroleum.
96,97
The po-
tential environmental and socio-economic benefits are substan-
tial, offering regions the opportunity to shift from fuel importers to
producers, utilizing locally abundant raw materials, and curtailing
environmental hazards of transportation.
98,99
However, inte-
grating microbe-generated biofuels into a circular economy re-
quires innovative scientific approaches and changes in agricul-
tural and industrial practices.
Autotrophic microorganisms, encompassing algae, bacteria,
and archaea, possess the unique ability to capture carbon
directly from the atmosphere or industrial waste gases, convert-
ing them into fuels. This represents the potential for producing
net zero carbon emission biofuels.
100
However, the number of
biofuels naturally produced by autotrophic bacteria is limited to
methane and acetic acid. Through genetic and metabolic engi-
neering, autotrophs have been the potential to produce a wider
array of fuels, including methane, ethylene and butanol,
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biological oil, and hydrogen,
101,102
but the cost of biofuel pro-
duction remains high.
103
Challenges involved in scaling growth
in industrial settings and enhancing fuel production efficiency
(particularly in photosynthetic bacteria) must be overcome to
reduce the gap in productions costs between biofuels and petro-
leum so that this technology can be more widely adopted.
103
Methane is a potent greenhouse gas, but it is also an abundant
carbon feedstock for microbes. It can be converted into valuable
products such as bioplastics, biofuels, nutraceuticals, and single-
cell proteins.
104
Furthermore,the transition into a hydrogen-based
fuel economy is rapidly increasing the production of low-cost
methanol, a versatilefeedstock for bioconversion. Methylotrophic
microorganisms utilize methane or methanol as sole carbon and
energy sources, driving their bioconversion into value-added
products.
105
Global-scale implementation of these methods re-
quires advancement of genetic tools, adaptation to industrial con-
ditions, and optimized bioreactor and bioprocess design.
106
Po-
tential environmental benefits, including significant reductions in
methane emissions and potential removal of atmospheric
methane, underscore the importance of this microbial approach
to mitigating climatechange. An estimated 50,000–300,000meth-
anotrophic bioreactors are predicted to absorb 240 megatons of
methane over 20 years.
107
The reduction of atmospheric methane
will become more critical with upscaling of hydrogen production
due to the depletion of the hydroxyl radical sink by hydrogen
release to the atmosphere that will extend the residence time of
methane, thus increasing its global warming potential.
108
In summary, microorganisms can provide important contri-
butions to the transformation of energy production and reduce
greenhouse gas emissions (Goals 7, 9, 12, and 13). Because
microbes can be cultivated across the globe by all nations
and can grow using diverse local feedstocks, they have the po-
tential to facilitate a transition toward affordable and clean en-
ergy by 2030. As such, they also have the potential to support
efforts to reduce inequalities (Goal 10) and to promote decent
work and economic growth (Goal 8). However, concerted ef-
forts in scientific innovation, agricultural and industrial prac-
tices, and global collaboration are essential to realizing the
full potential of microbial solutions in shaping a sustainable en-
ergy future.
SYNTHESIZING AND RECYCLING PRODUCTS
SDGs: 3, 6, 7, 8, 9, 10, 12, 13, 14, 15
20
th
century society converted billions of liters of petroleum yearly
into a variety of chemicals and materials. Most of this multi-trillion
dollar per year industry is located in a few well-developed coun-
tries and uses processes that have a negative environmental
impact. For these and other reasons, there have been recent calls
to create a circular bioeconomy to reduce greenhouse gas emis-
sions and generate products from renewable raw materials
109–111
(Figure 3). The contribution of a circular bioeconomy to a 21
st
cen-
tury industrial revolution is large since estimates are that up to
60% of the inputs to the global economy could, in principle, be
produced biologically.
111
Below, we make thecase that microbes
can generate low greenhouse gas chemicals and materials while
providing economic and environmental benefits to citizens and
communities around the world (Goals 7, 9, 12, and 13).
Available renewable raw materials to feed this circular bio-
economy include billions of tons of organic residues that involve
non-food animal and plant material, crops grown specifically for
conversion into chemicals and materials, manure, waste from
municipal and industrial activities, as well as carbon dioxide
sequestered from the atmosphere or generated by indus-
try.
12,112–114
The majorityof these organic residues are either com-
busted (releasingcarbon dioxide) as a source of heat and power or
releasedto the environment, which can contributeto phosphorous
or nitrogen accumulation and have other negative ecosystem im-
pacts. While developing a circular bioeconomy to generate valu-
able products from these abundant raw materials will require
changes in agricultural and industrial practices (Goal 9), its envi-
ronmental, economic, and societal benefits (Goals 3, 6, 10, 13,
14, and 15) are enormous given the availability of raw materials
in well- and less-developed regions across the globe.
98,99
Microbes can serve as catalysts to power a new circular bio-
economy. Microbes have performed chemical transformations
longer than humans and operate as circular economies them-
selves. These ubiquitous organisms have driven the evolution
of and supported life on the planet, and processes based on their
activity can be environmentally and economically sustainable
(Goals 7, 9, 12, and 13). Examples include microbial production
of hydrocarbons and hydrogen, the >100-year-old industrial use
of acetone and butanol fermentations,
115
and using microbial ni-
trogen fixation to reduce dependence on fertilizer generated by
the energy-intensive Haber-Bosch process.
101,102,116
While still
in its infancy, there are both emerging and existing examples
of the potential for industry to harness the metabolic power of mi-
crobes to convert an abundant supply of industrial carbon mon-
oxide and dioxide into cost-competitive bio-based fuels, chem-
icals, and textiles.
117
In addition, studies and initiatives have both
identified bottlenecks or demonstrated the ability to generate
cost-competitive microbial products from abundant non-food
lignocellulosic biomass
118
and dairy coproduct residues.
119
These examples provide a roadmap for how to develop microbial
factories that convert other abundant raw materials into a suite of
valuable chemicals and materials with local, regional, and global
markets.
120,121
The time is ripe to develop microbial cell factories. Recent ad-
vances in genomics have uncovered a plethora of previously un-
known microbial activities with potential societal utility.
109,122
Genomic datasets also provide an ever-growing set of existing
and modified genes to deploy for low-cost synthesis of hydro-
carbon fuels, methane, substitutes for petrochemicals, or even
other compounds that cannot be generated in a cost- or environ-
mentally effective manner by today’s industries (Goal 9). Tapping
the chemical potential locked in the genomes of native or engi-
neered microbes, or the combined activity of microbial commu-
nities, can help design new biological catalysts for a circular bio-
economy.
122
The potential exists for either use of the resulting
microbial products directly or after they are chemically modified
to increase their societal value and utility.
Life cycle analysis predicts that the benefits of a circular bio-
economy will be maximized by locating biorefineries near the
raw materials and infrastructure needed to move materials
from producers to consumers.
123
Success will ultimately require
models that accurately predict raw material supply, costs of
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purchase and transport to refineries, and expenses to produce,
purify, and distribute products.
99,123
Supply chain models pre-
dict that a microbe-powered circular bioeconomy can provide
new high-technology and other jobs to both industrialized na-
tions and less-developed regions, especially if one considers
producing materials locally and moving raw materials from de-
pots to centralized facilities of different scales.
20,110,124,125
It
would also be an integral part of an agile supply chain that can
respond to changes in raw material supply or consumer demand
(Goals 8 and 11). While the cost of building and operating these
biorefineries will require public and private sector support, the
return on this investment can be substantial, especially in low-in-
come regions of the world that need industrial development
(Goals 9 and 11). For example, a microbe-powered circular bio-
economy can provide new high-value economic opportunities to
raw materials producers, attract considerable investment, in-
crease highly skilled domestic workforces, and, in turn, improve
education and personal financial stability, especially in less-
developed and low-income regions of the globe
110,111
(Goals
10, 11, and 12). Moving to a microbe-powered circular bio-
economy can create a new industrial ecosystem that is sustain-
able, resilient to natural or geopolitical disruptions in supply
chains, generates decarbonized products from local renewable
raw materials, and provides socio-economic opportunities to
more regions of the globe. Over time, movement to a microbe-
powered circular bioeconomy will pay considerable dividends
to the planet and its inhabitants.
BIOREMEDIATION
SDGs: 1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
Current and past industrial and agricultural activities have left us
with a legacy of polluted habitats around the world that threaten
human health (Goal 3), the functioning of natural ecosystems
(Goals 14 and 15), and their ecosystem services such as safe
food (Goal 2) and clean water
126
(Goal 6). Bioremediation is a na-
ture-based process that employs living organisms (e.g., bacte-
ria, archaea, fungi, and microalgae and/or their metabolic prod-
ucts) to remove, detoxify, immobilize, and extract contaminants
(e.g., hydrocarbons, polychlorobiphenyls, pesticides, herbi-
cides, and/or heavy metals) in a variety of environmental
matrices (e.g., soils, sediments, and water).
127
Bioremediation interventions can use different approaches,
including the enhancement of the capability of natural microbial
assemblages to degrade/stabilize contaminants (e.g., bio-
stimulation through the addition of nutrients or bioventing
Figure 3. Components of a microbe-powered circular bioeconomy
Left: examples of abundant renewable raw materials (non-food organic residues, CO
2
, and other gaseous wastes) to feed a microbially powered circular bio-
economy. Right: examples of potential products generated from these raw materials in a microbe-powered biorefinery (fuels, power, materials, chemicals, and
biochar).
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through the insufflation of oxygen) and the addition of microor-
ganisms with desired remediation capabilities to the host or envi-
ronment (i.e., bioaugmentation
128
). Bioremediation allows an effi-
cient, safe, and cost-effective decontamination of environmental
matrices to levels that cannot be achieved by conventional treat-
ments (e.g., pyrolysis, landfilling, and soil washing).
129,130
In addi-
tion, it reduces the risks of secondary contamination and ensures
a lower carbon footprint
131,132
(Goal 13). A biostimulation exper-
iment based on the addition of inorganic nutrients (nitrogen and
phosphorous) to sediments highly contaminated by polycyclic
aromatic hydrocarbons (PAHs) revealed a >90% reduction in
PAH and greater environmental benefits (estimated in terms of
CO
2
equivalents) compared with traditional approaches (i.e.,
disposal of sediments in landfill areas).
132
Microbial bioremedia-
tion has been proven to be effective for wastewater treatment to
degrade recalcitrant contaminants (e.g., landfill leachates, tex-
tiles, and pharmaceutical wastes), which are generally left un-
treated by conventional wastewater processes. Bacterial and
fungal enzymes such as azoreductase, lignin peroxidase, and
laccase, as well as microalgae (e.g., Chlorella vulgaris UMACC
001), can accelerate the degradation of persistent organic dyes
in textile wastewater.
133,134
Microbial bioremediation can also
degrade toxic compounds while transforming organic waste
into biofertilizers and biofuels, thus being highly cost-effective
135
(Goal 8).
Microbial bioremediation can also contribute to plastic pollu-
tion abatement, especially of micro- and nano-plastics that are
extremely difficult to remove using traditional approaches.
Most global plastic production ends up in the ocean,
136
with
plastic pollution found from the surface down to the deep sea-
floor.
137–139
The microbial communities colonizing plastic sur-
faces
140
include bacteria and fungi and ‘‘pit-forming’’ microbes
that modify the surface of plastics,
141
contributing to the degra-
dation of several polymers.
142,143
For example, the plastic-de-
grading bacterium Ideonella sakaiensis is able to slowly degrade
polyethylene terephthalate, commonly known as PET.
144
A
crucial first step is the enzymatic breakdown of the plastic poly-
mer into its monomers terephthalate and ethylene glycol, which
are used by the bacterium as a carbon source for growth. The
monomers can also be recycled to produce new plastics in an
environmentally friendly way.
145,146
Companies are beginning
to scale up this process, with the company CarBios announcing
a new plant opening in 2025 that aims to recycle 50,000 tons of
PET plastic per year.
147
PET is just one kind of plastic, and other
plastics will have their own challenges.
148,149
Yet, further
research investment has the potential to lead to new technolo-
gies that can contribute to the clean-up of plastic pollution (Goals
6 and 14).
Among bioremediation approaches, rhizoremediation, ex-
ploiting the high potential of root-associated microorganisms
to degrade organic pollutants, appears to be particularly effec-
tive in improving the success of phytoremediation of contami-
nated soils.
150
For example, the rhizoremediation of agricultural
soils in Italy heavily polluted by polychlorinated biphenyls (PCBs)
reduced the concentration of such contaminants by approxi-
mately 20% in 18 months.
151
Other investigations at a German
site historically contaminated by diesel fuel hydrocarbons re-
vealed that rhizoremediation can enhance biodegradation by
up to 96% in 60 days.
152
With the advent of -omics approaches,
it has been possible to identify key rhizome microbiomes and
their metabolites with unprecedented resolution, thus imple-
menting microbiome-assisted restoration actions not only of
terrestrial plants but also of mangroves and seagrasses.
153
How-
ever, rhizoremediation is still not widely adopted by accredited
soil remediation experts, partly due to the inconsistencies in re-
sults (depending on the soil type and plants used), the slow time
frame required to achieve outcomes, and a lack of communica-
tion between scientists and practitioners.
154
More research is
needed to develop more consistent methods that could be
adopted at larger scales.
154
Microbial fuel cells are an innovative bioremediation practice
in which metabolic activities of electroactive bacteria (such as
such as Geobacter,Shewanella,Pseudomonas, and Rhodo-
ferax)
155
transform organic and inorganic matter into
bioelectricity.
156
This allows electricity to be generated from
wastewater treatment plants, reducing operating costs and en-
ergy consumption.
157
Microbial fuel cells can generate around
30 W m
2
of electricity, 1m
3
day
1
of biohydrogen, and in-
comes of as much as $2,498.77 310
2
/(W m
2
) annually
through wastewater treatment and energy generation alone.
157
Bioleaching is a remediation process used to naturally extract
metals (e.g., copper, zinc, lead, lithium, and nickel) from different
matrices (e.g., electronic waste, mobile phones, spent batteries,
and other mineral waste) by exploiting the microbial ability to
oxidize minerals. This approach is an eco-sustainable alternative
to (highly impacting) traditional metallurgical processes (e.g.,
conventional fusion).
158,159
Among fungi, the Aspergillus and
Penicillium genera appear to be the most effective in biological
leaching. These genera have been employed for metal extraction
from oxidic ores of different metals (e.g., nickel, iron, chromium,
titanium and quartz sands, refractory gold, silver, copper man-
ganese, cobalt, and zinc).
160
Among bacteria, Acidithiobacillus
ferrooxidans and Acidithiobacillus thiooxidans can efficiently
mobilize the main metals of electronic waste (i.e., copper in
printed wire boards) together with other metals, such as zinc
and lead.
161
Based on existing information, bioleaching is a valu-
able approach for the management of mine waste, reducing the
environmental impact of mining activities and the release of toxic
elements, thus facilitating the safe and efficient recovery of
metals.
129
The implementation of eco-compatible bioremediation can
contribute to the renewable energy sector and to sustainable
economic growth (Goals 7 and 8). At the same time, the imple-
mentation of microbial bioremediation can provide a relevant
contribution to the sustainable management of waste (Goal 12)
and the health of polluted terrestrial (and 15) and marine (Goals
14) habitats. As a result, these impacts are directly relevant for
improving human health and well-being (Goal 3), ensuring better
access to natural resources (Goal 6), basic services (Goals 1, 2,
and 11), and fairer living conditions around the world (Goal 10).
Yet, although bioremediation has great potential, many polluted
sites contain complex mixtures of contaminants that present mi-
crobes with significant metabolic and ecophysiological chal-
lenges. Moreover, the implementation of bioremediation solu-
tions at large spatial scales remains challenging, particularly
under changing environmental conditions
132
(Goal 9). To carry
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out such interventions, it will be necessary to develop an inte-
grated approach including the best bioremediation techniques
and the advanced engineering technologies (including remote
sensing and GIS-based mapping) to assess the extent of
contamination/damage and to understand the spatial and tem-
poral variations of the impacted sites.
162
FACILITATING HEALTHY ECOSYSTEMS
SDGs: 1, 2, 3, 6, 11, 13, 14, 15
Microorganisms overwhelmingly dominate the diversity of life on
Earth, with an estimated 1 trillion species existing across the
globe.
3
In addition, microbes shape the biochemical landscape
by performing important metabolic functions,
8
including photo-
synthetic oxygen production, the degradation of organic mole-
cules, nitrogen fixation, detoxification, nutrient release, and
transformation of greenhouse gases. All of these processes are
fundamental to supporting life in terrestrial, freshwater, and ma-
rine ecosystems and are vital to the health and well-being of hu-
manity. As such, by maintaining the functionality of both natural
and managed ecosystems, microbes play a key role in gener-
ating clean water (Goal 6), the regulation of our climate (Goal
13), life below water (Goal 14), and life on land (Goal 15).
When anthropogenic factors such as ecological degradation
and climate change lead to the breakdown of microbial com-
munities, they fundamentally undermine the capacity of eco-
systems to support other life.
16,71
As such, there is growing
awareness of the need to include microbial diversity into con-
servation planning, both to protect the high diversity that mi-
crobes represent and to preserve ecological functioning.
16,163
To facilitate more targeted conservation of microbial diversity,
a growing body of research has begun to explore and charac-
terize hotspots of microbial diversity across the globe.
163,164
Figure 4. Microbial richness hotspots (the
most diverse areas across the globe) are
poorly protected
Microbial richness data from Guerra et al.
163
was
extrapolated to the global scale using Random
Forest machine learning following van den Hoogen
et al.,
165
and area with richness values in the top
95
th
percentile (‘‘hotspots’’) was overlaid with
polygons from the World Database on Protected
Areas.
166
Only 13.4% of the global hotspot areas
of microbial richness fall within strict conservation
areas. A further 22.8% are located in less strictly
protected areas.
However, in general, there is little spatial
overlap between the regions of high mi-
crobial diversity and existing protected
areas across the globe, with a possible
67.5% of microbial biodiversity hotspot
regions existing outside of protected
areas (Figure 4). This highlights the
need for conservation priorities to be
readjusted if they intend to protect mi-
crobial diversity and its associated
ecosystem services.
Along with improving efforts to conserve existing microbial
biodiversity, there is a growing awareness of the need to restore
microbial communities that have been degraded. Indeed, the soil
microbiome often represents a key limiting factor for ecosystem
recovery in both natural and managed ecosystems.
16
Across the
globe, inoculants of diverse soil communities (e.g., via soil trans-
plants, spore extracts, and cultured strains) have been shown to
increase ecosystem recovery by an average of 64%.
16
It is likely
that these impacts are driven by increases in soil metabolism and
stability that enhance plant growth, survival, and biodiversity,
167
and the effects tend to have the greatest beneficial impacts in
more degraded soils.
168
Direct manipulation of the microbiome
will be enabled through much-needed work identifying when
and where different types of inoculation are successful. Micro-
biome-based approaches (including the use of probiotics) are
also being used to control diseases in wild animal popula-
tions.
169
However, because land use practices and climate
change impact different ecosystems in different ways,
14
micro-
biome-based approaches need to be tailored to the target sys-
tem. In order to avoid the damaging impacts of invasive species
and maximize the beneficial impacts on ecological recovery, mi-
crobial inoculations or transplants are most effective when using
native species from nearby local environments.
168
Metagenomic
sequencing and other ‘‘omics’’ approaches
170
can provide valu-
able information regarding microbial diversity and functional ca-
pacity and can be used as biomonitoring tools to assess micro-
bial communities in restoration interventions.
171,172
Despite the potential of microbes to improve ecosystem
health, substantial research is still needed to make full and
informed use of microbial biotechnology in land conservation
and restoration practices across agricultural, urban, and natural
ecosystems. Microbial inoculation methods are not yet widely
implemented in the field, and scaling-up methods to be applied
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at the landscape level requires further development and full eval-
uation of risks.
16,79,173
However, a growing body of evidence
supports the potential for native, diverse microbial communities
to improve yields in both natural and managed environ-
ments.
174,175
Similarly, methods to control disease in animal
populations need to be optimized, as they often need to be
applied repeatedly or at specific stages of the life cycle.
169
Because the majority of microbial species remain undiscov-
ered,
3
significant investment is needed to improve our under-
standing of the potential for using microorganisms to restore
life on land (Goal 15).
As well as enhancing ecological recovery, microbes can also
represent an important biological control tool for limiting the
spread of invasive or harmful species. For example, across the
globe, harmful algal and cyanobacterial blooms and waterborne
pathogens (e.g., Vibrio cholerae and Salmonella typhi) represent
key threats to the water quality of lakes, rivers, and coastal
waters
176
(Goals 6 and 14). Microbial-mediated reduction of
nutrient loads can be managed to help suppress damaging algal
blooms
177
and can yield pathogen reduction co-benefits,
178
even though benefits may take years to accrue if high amounts
of nutrients have already accumulated in the sediments. Recent
research on microbial control of harmful algal blooms has iden-
tified several viruses, bacteria, and fungi that show algicidal ac-
tivity,
179–181
as well as microorganisms that can degrade algal
toxins
182
(Goal 6).
Over 30% of people in tropical countries are directly depen-
dent on nature for their basic needs,
183
and the rest of the global
economy is indirectly underpinned by the existence of natural
ecosystems. As such, microbial solutions to improve the health
and diversity of natural ecosystems will ensure that these sys-
tems continue to provide a sustainable source of food and clean
water (Goals 1, 2, 6, and 11) and that disease outbreaks are
reduced in frequency and severity (Goal 3).
GLOBAL BIOGEOCHEMICAL CYCLES AND CLIMATE
CHANGE
SDGs: 1, 2, 3, 4, 6, 10, 11, 13, 14, 15, 16
Microbes have been central drivers of the evolution of Earth’s
atmosphere over the last 3 billion years, including the oxygen-
ation of the Earth’s early atmosphere that allowed life to flourish
and higher forms of life to evolve (Goals 14 and 15). They
remain primary drivers of modern-day carbon and nutrient
cycling across the globe.
164
As such, they play a crucial role
in regulating the atmospheric composition and climate.
Currently, there are growing concerns that the climate-induced
acceleration of microbial-mediated biogeochemical processes
has the potential to accelerate CO
2
emissions into the atmo-
sphere.
15,184
However, the scale of these biochemical impacts
means that they also have the potential to act as a powerful ally
in achieving Goal 13 of ‘‘climate action’’ if we can capitalize on
solutions that enhance the microbially mediated mitigation of
CO
2
(carbon dioxide), CH
4
(methane), and N
2
O (nitrous oxide)
emissions.
185
Land use change and agriculture provide considerable oppor-
tunities for deliberate mitigation of global warming using mi-
crobes. As mentioned above, microbial inoculations that
enhance productivity and soil carbon sequestration have the po-
tential to enhance carbon storage in both managed ecological
health
168
and natural
167
ecosystems. Moreover, any mecha-
nisms that enhance photosynthesis and/or reduce the rate of
organic carbon mineralization will also increase terrestrial carbon
sequestration. In particular, the restoration of degraded peat-
lands, for instance, could yield a microbially mediated reduction
in emissions of around 0.8 Gt of CO
2
equivalents per year by
2030
186
(Goals 13 and 15). Soil amendments such as biochar
and compost can also enhance carbon sequestration by
increasing its recalcitrance to microbial decomposition, while
microbial uptake and deposition of root-exuded carbon com-
pounds in the rhizosphere of deep-rooted perennial grasses
could also be leveraged to enhance soil carbon stocks.
185
The
use of microbes to reduce CO
2
emissions is already well estab-
lished in the form of biofuel production, either via conversion of
lignocellulosic feedstocks or as the feedstock itself (e.g., mi-
croalgae).
Microbially mediated CH
4
fluxes dominate anthropogenic
emissions, with ruminant livestock, waste management, and
rice agriculture all being significant global sources.
187
Improved
feed quality and feed additives are proven methods to reduce
CH
4
emissions from enteric fermentation during the digestion
process in ruminants. There is also potential for systematic se-
lection of the gut microbiome in ruminant livestock through
genomic selection of low-emission traits.
188
Additionally, micro-
bially derived meat substitutes can reduce reliance on rumi-
nants, thereby cutting associated emissions.
81
In the waste
management sector, options range from enhancing aeration of
wastes (to limit methanogenesis) through encouragement of
methanotrophy (e.g., landfill cover soils) to deliberately opti-
mizing methanogenesis to generate CH
4
for substitution of fossil
fuels (e.g., anaerobic digestion). In rice agriculture, established
microbially mediated approaches to mitigation of CH
4
emis-
sions, such as drainage and harvest residue management, could
be complemented by development of new rice cultivars aimed at
modifying root carbon allocation.
101
N
2
O emissions from soils and sediments, produced by mi-
crobes, are increasing due to human-induced nitrogen enrich-
ment.
189
Nitrogen fertilization of farmlands is the main contrib-
utor, with spill-over effects on natural ecosystems (Goal 15).
Significant mitigation relies on modifying microbial nitrogen
transformations in farmed soils. N
2
O is a by-product of ammonia
oxidation, and inhibiting ammonia-oxidizing bacteria that pro-
duce more N
2
O than their archaeal counterparts is a promising
approach. Denitrifying bacteria are also attractive targets
because reducing their overall N
2
O/N
2
product ratio (R) deter-
mines farmland emissions of N
2
O. Lime application lowers R
by promoting synthesis of functional N
2
O-reductase.
190
Another
promising approach is bioaugmentation of denitrifying bacteria
that reduce, but do not produce, N
2
O.
191
Such bacteria can be
effectively vectored by organic waste, with a relatively long-last-
ing effect on N
2
O emissions, if selected for the ability to grow in
organic waste and soil.
192
Field experiments demonstrated a
50%–95% reduction of N
2
O-emission by fertilization with
organic waste in which such bacteria had been grown to high
cell densities.
90
The technology has the potential to reduce Euro-
pean-wide anthropogenic N
2
O emissions by 5%–20%.
90
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Marine and freshwater systems contribute 50% of global pri-
mary production, largely driven by the photosynthetic activity of
cyanobacteria and unicellular eukaryotic algae. Hence, aquatic
microorganisms play a key role in global carbon sequestration
and provide the energy to drive aquatic food webs (Goal 14).
Aquatic microorganisms also play an important role in climate
regulation through the production and release of organic com-
pounds to the atmosphere that subsequently influence aerosol
loads, aerosol properties, and cloud formation.
193–195
However,
aquatic microbiomes are also highly sensitive to climate-driven
stressors, including increased water column (density) stratifica-
tion and nutrient stress from climate warming, ocean acidifica-
tion from rising atmospheric carbon dioxide, oxygen depletion,
and extreme climatic events (e.g., marine heatwaves).
15,196
Im-
pacts of these cumulative stressors include shifts in microbial di-
versity and species composition, changes in primary productiv-
ity, disease outbreaks, altered nutrient or gas cycling (including
the enhanced release of potent greenhouse gases such as
methane), and disruption of symbiotic and virus-microbe inter-
actions.
197,198
Microbial solutions to climate-driven stressors in water include
natural processes and those that humans might manipulate and
harness. It is essential that we understand the ramifications of
both. Natural processes include metabolic feedbacks that
buttress shifts in substrate availability. For example, some
phytoplankton upregulate nitrogen fixation under ocean acidifi-
cation,
199
thereby partially compensating for decreasing upwell-
ing of nutrients.
200
Other phenomena influenced by climate
change, such as the gradual loss of oxygen from the subsurface
ocean and coastal waters
201,202
are associated with microbial
communities producing and consuming potent greenhouse
gases (e.g., methane and nitrous oxide).
203
Warming hastens
respiratory return of carbon dioxide to the atmosphere, thereby
decreasing carbon deposition to marine sediments (positive
climate feedback).
204
Warming may also elevate plankton nitro-
gen-to-phosphorus ratios, thereby increasing carbon sequestra-
tion (negative climate feedback) because carbon-to-nitrogen
ratios are relatively invariable.
205
Encouragingly, this natural
complexity suggests potentially overlooked microbial con-
straints on climate-driven phenomena.
Some emerging lines of research highlight the potential to
harness microbial processes for large-scale geoengineering to
enhance carbon sequestration (e.g., iron fertilization of the
oceans).
206
Although such large-scale mechanisms may not
yet be advisable without considerable advances in our under-
standing of the downstream consequences,
206,207
many micro-
bial solutions at local scales present more manageable options.
For example, biofuel production involving freshwater and coastal
microbes may provide an alternative for fossil fuels, with the po-
tential to reduce arable land demands from traditional biofuel
production.
208
Furthermore, microbial conversion of methane
to high-value bioproducts (e.g., methanol and biodegradable
plastics) may offer a sustainable solution to reduce greenhouse
gas emission.
209
In all these cases, accelerating bioengineering
research is needed, including expanded libraries of genetically
manipulatable strains and upscaling of culturing techniques to
improve potential economic benefits of biofuel production and
other forms of microbial carbon sequestration.
Microbes therefore underpin global fluxes and the potential for
mitigation of all 3 major anthropogenic greenhouse gases.
Improved understanding and greater application of microbial
ecology—such as through manipulation of plant-soil-microbial
interactions or marine primary producers to enhance net carbon
gain—has the potential to make a very significant contribution
toward improving climate action (Goal 13) and subsequently
life in aquatic and terrestrial ecosystems (Goals 14 and 15).
Given the multifaceted implications of climate change for
poverty, hunger, healthcare, clean water, and education,
210
mi-
crobial-based climate mitigation solutions have the capacity to
contribute to numerous other SDGs (Goals 1, 2, 3, 4, 6, 10, 11,
and 16).
PARTNERSHIPS FOR THE GOALS (GOAL 17)
SDG 17, ‘‘partnerships for the goals,’’ aims to strengthen ways
of implementing the SDGs and revitalize global partnerships for
achieving sustainable development.
9
Our review highlights that
the consideration of microbes and microbial-based technolo-
gies may be critical for achieving each of the SDGs. More
importantly, this review reveals how microbial technologies
have the potential to provide synergistic opportunities for
achieving multiple SDGs simultaneously, facilitating collabora-
tion and alignment in achieving those goals (Figures 2 and 5).
For example, the central role of soil microbial diversity in pro-
moting carbon storage on land
164
suggests that efforts to pro-
mote healthy microbial communities can contribute synergisti-
cally to both climate (Goal 13) and biodiversity (Goals 14 and
15) goals.
16
As such, explicitly recognizing this role of microbial
diversity in the official documentation for the United Nations
Framework Convention on Climate Change (UNFCCC) and
the Convention on Biological Diversity (CBD) can help provide
a common lexicon to develop partnerships for organizations
and governments to achieve both sustainability targets simulta-
neously. In Figure 5, we highlight diverse microbial roles that
are conceptually linked to achieving the SDGs, presenting
different pathways for potential partnerships in achieving multi-
ple sustainability targets.
Some SDGs are more directly influenced by microbes than
others (Figure 5). Specifically, microbes may not initially appear
directly relevant for achieving quality education (Goal 4), gender
equality (Goal 5), or peace, justice, and strong institutions
(Goal 16). However, the highly interdependent nature of the
SDGs means that microbial advances in other areas (e.g., food
production, healthcare, and bioremediation) will have immediate
knock-on consequences for all aspects of equity, peace, and
justice. This becomes especially relevant for Indigenous com-
munities that steward 80% of global biodiversity but are often
overlooked in strategic global planning and excluded from the
direct benefits provided by natural product development.
211,212
Microbes are already being deployed in bioremediation efforts
to decontaminate ecosystems disrupted by extractive mining
projects that disproportionately impact marginalized commu-
nities,
213
thereby contributing to equity SDGs. The plethora of
microbially relevant interactions between SDGs that we have
identified (Figure 5) illustrates that microbes can indeed accel-
erate progress toward all goals.
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5206 Cell 187, September 19, 2024
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Ultimately, the universal roles of microbes in driving
biochemical processing of elements make them relevant to
every aspect of sustainability. The clustering of microbial func-
tions into 7 overarching areas (Figure 2) reveals the significant
amount of overlap between the sustainability implications of
different microbial solutions. While it is impossible to charac-
terize the full dimensionality of these partnerships across all
natural and human systems, our synthesis highlights clear clus-
tering of microbial processes that are relevant for different
groupings of SDGs (Figure 2). Increased familiarity of public
and private sector decision-makers with these general microbi-
al processes may be key to improving efforts to address the
combined global sustainability challenges facing humanity in
the coming century.
Figure 5. Microbe-relevant positive interactions between the SDGs
Using microbes to directly advance each SDG will likely indirectly advance other SDGs (outgoing arrows). For example, microbial biotechnology used to reduce
hunger (Goal 2) will also indirectly reduce poverty and inequality (Goals 1, 5, and 10), improve health (Goal 3), educational experience (Goal 4), community and
commercial sustainability (Goals 11 and 12), and peace (Goal 16). Detailed descriptions of all arrows are provi ded in Table S1. Although Goal 17 cannot be directly
advanced by microbial technology, outgoing links are shown to all other SDGs because including microbes in international and organizational policy agreements
will likely benefit all goals (see section ‘‘partnerships for the goals’’).
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CONCLUSIONS
Accelerating the transition toward a sustainable future requires
that we capitalize on all tools in our arsenal, including those
provided by the most ecologically diverse organisms with the
most powerful catalytic capacity in the natural world. Our re-
view highlights a range of microbial innovations that have the
potential to facilitate a rapid transition toward a sustainable
economy (Table 1). Our overarching conclusion—that microbial
processes are fundamental to achieving the SDGs—may seem
trivial, given that they underpin all life on Earth. However, the
real insight is the extent of overlap in the importance of micro-
bial innovations that can simultaneously help us accelerating
progress toward achieving multiple sustainability agendas
(see Figures 2 and 5). With increasing regulatory pressure for
governments and organizations to achieve a range of sustain-
ability targets, identifying common frameworks to address mul-
tiple goals is an urgent priority. The broad importance of micro-
bial innovations means it is possible to identify synergies that
can reveal pathways to achieving multiple sustainability targets.
For example, if improving soil microbial diversity can contribute
to our biodiversity (Goals 14 and 15), climate (Goal 13), and
food security (Goal 2) goals, then it may present an efficient
and cost-effective avenue for accelerating impact. Similarly, if
microbial-based bioreactors can drive transitions toward sus-
tainable energy production (Goal 7), materials transforma-
tions/production (Goal 12), and infrastructure (Goal 9), then
they represent powerful opportunities for accelerating sustain-
able development. Such synergistic roles of microbial pro-
cesses in facilitating sustainable transitions across different
sectors highlight that they can provide decision-makers with
a common lexicon for collective action toward simultaneously
addressing multiple sustainability goals.
Given the ubiquitous roles of microbial research and technol-
ogy across all SDGs, it is surprising that microorganisms
remain largely absent from the intergovernmental policy agree-
ments and multilateral treaties of the United Nations. At the
highest level, the biggest challenge is public and political
awareness of the central role of microorganisms and changing
behavioral norms so that the necessary microbial solutions can
be adopted.
214
Funding for downstream development is
another critical hurdle limiting the widespread adoption of mi-
crobial technologies. As such, the scaling of microbial innova-
tions will require the establishment of proactive financial and
regulatory policies that recognize their unique potential.
Following recent calls for decision-makers to recognize the
importance of microbes in guiding action on climate change,
15
our review highlights the need for similar consideration across
the full range of our international sustainability agendas. To
build a sustainable future on this planet, we must work with
our oldest ancestors.
ACKNOWLEDGMENTS
We thank Chelsea Mamott and the Wisconsin Energy Institute for inspiration
for Figure 3, Chrysa Chouliara for help producing Figure 5, Irene Suarez for
policy guidance and oversight, and Gail Gallie for guidance and insights
about the SDGs. Funding was provided by the Bernina Foundation and
DOB Ecology.
AUTHOR CONTRIBUTIONS
Conceptualization, T.W.C., L.G.v.G., R.R., and R.C.; writing – original draft,
T.W.C., L.G.v.G., R.R., C.C., R.D., T.J.D., J.H., L.Y.S., J.K.T., K.T., M.Z.A.,
L.R.B., M.B., M.J.B., P.W.B., I.B., C.S.D., C.M.F., J.K.J., B.K., K.M.-M.,
J.A.N., D.P., M.P., J.L.R., D.R., J.V.R., V.R., W.J.R., B.K.S., G.R.S., F.J.S.,
M.S., M.J.H.v.O., and N.S.W.; writing – review and editing, all authors who
wrote the original draft plus C.M.Z.; figures, L.G.v.G., J.v.d.H., and T.J.D.
DECLARATION OF INTERESTS
M.Z.A. is on the board of the Native BioData Consortium (NBDC; https://
nativebio.org/); D.R. is co-chair of Just Transition Commission (https://www.
justtransition.scot/); J.K.J. is chair of the Scientific Advisory Board for Oath
Inc. (https://www.oathinc.com/); J.A.N. has a patent holding: North JA, Tabita
FR, Young SJ, and Murali S. 2021. Nitrogenase-like enzyme system that cat-
alyzes methionine, ethylene, and methane biogenesis. P2021-099-6249;
WIPO 20240060037.
SUPPLEMENTAL INFORMATION
Supplemental information can be found online at https://doi.org/10.1016/j.cell.
2024.07.051.
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Table 1. Recommended actions to facilitate achieving the SDGs that can be directly influenced by microorganisms
SDG Recommendations
1, no poverty implement in appropriate countries cost-effective, scalable bioremediation procedures
to produce local jobs and advance local expertise in microbiology
increase availability of microbes that improve food production and preservation practices
require benefit-sharing models in microbial development projects that target
under-resourced communities to alleviate poverty
2, zero hunger invest in microbiome research and development for agriculture and aquaculture
implement solutions that enhance in situ production of cost-effective, scalable
methods for microbiome-based products
establish robust education and training programs to inform food producers