Stephen M. Techtmann

Michigan Technological University | MTU · Department of Biological Sciences

Introduction: Accumulation of plastic waste in the environment is a serious global issue. To deal with this, there is a need for improved and more efficient methods for plastic waste recycling. One approach is to depolymerize plastic using pyrolysis or chemical deconstruction followed by microbial-upcycling of the monomers into more valuable produc...

Food insecurity is a pressing global concern; concurrently, plastic pollution has emerged as a growing crisis on a worldwide scale. To address both of these issues, we propose a sustainable chemical and biological technology that converts end-of-life plastics into edible, microbial-origin food. We delve into the utilization of microbes, enriched fr...

We report the metagenome sequences of two microbial cultures that were grown with chemically deconstructed plastic products as their sole carbon source. These metagenomes will provide insights into the metabolic capabilities of cultures grown on deconstructed plastics and can serve as a starting point for the identification of novel plastic degrada...

Over half of the world's plastic waste is landfilled, where it is estimated to take hundreds of years to degrade. Given the continued use and disposal of plastic products, it is vital that we develop fast and effective ways to utilize plastic waste. Here, we explore the potential of tandem chemical and biological processing to process various plast...

Most plastic waste accumulates in landfills or the environment. Natural microbial metabolisms can degrade plastic polymers. Unfortunately, biodegradation of plastics is slow even under ideal conditions; depolymerization of plastic is the rate limiting step. Rapid chemical depolymerization yields biodegradable plastic monomers, improving biodegradat...

There is a growing need for biological and chemical methods for upcycling plastic waste streams. Pyrolysis processes can accelerate plastic depolymerization by breaking polyethylene into smaller alkene components which may be more biodegradable than the initial polymer. While the biodegradation of alkanes has been extensively studied, the role micr...

Most polyethylene terephthalate (PET) plastic waste is landfilled or pollutes the environment. Additionally, global food production must increase to support the growing population. This article explores the feasibility of using microorganisms in an industrial system that upcycles PET into edible microbial protein powder to solve both problems simul...

The environmental implications of unconventional oil and gas extraction are only recently starting to be systematically recorded. Our research shows the utility of microbial communities paired with geochemical markers to build strong predictive random forest models of unconventional oil and gas activity and the identification of key biomarkers.

Antimicrobials such as nanoparticles and biocides are used to control microbial growth. We used Escherichia coli to study the process of acquired resistance to silver nanoparticles (Ag-NP) and the industrial biocide DBNPA when grown in sub-MICs. We determined the MICs of these two antimicrobials against E. coli. We then performed an experimental ev...

Here, we report the draft genome sequence of three glutaraldehyde-resistant isolates from produced water from hydraulic fracturing operations. The three strains were identified as Marinobacter sp. strain G11, Halomonas sp. strain G15, and Bacillus sp. strain G16. The genome sequences of these isolates will provide insights into biocide resistance i...

Polyethylene plastics are a major source of industrial and household wastes, the majority of which end up in the environment or in landfills. These wastes pose challenges for microbial biodegradation due to their polymeric structure. There is a critical need for a process that aids in the breakdown and reuse of plastic compounds. Pyrolysis of high-...

Freshwater systems are vulnerable to contamination by oil extraction and transportation. Thus, it is critical to understand how large freshwater ecosystems such as the Great Lakes will respond to released oil. In this study, we investigated differences in the microbial response to oil in the Straits of Mackinac at different times throughout the yea...

Our study goal was to investigate the impact of biocides and nanoparticles (NPs) on the microbial diversity in a hydraulic fracturing impacted stream. Biocides and NPs are known for their antimicrobial properties and controlling microbial growth. Previous work has shown that biocides can alter the microbial community composition of stream water and...

Advances in nucleic acid sequencing technology have enabled expansion of our ability to profile microbial diversity. These large datasets of taxonomic and functional diversity are key to better understanding microbial ecology. Machine learning has proven to be a useful approach for analyzing microbial community data and making predictions about out...

Many aquatic environments are at risk for oil contamination and alkanes are one of the primary constituents of oil. The alkane hydroxylase (AlkB) is a common enzyme used by microorganisms to initiate the process of alkane-degradation. While many aspects of alkane bioremediation have been studied, the diversity and evolution of genes involved in hyd...

Aims: This study explores the microbial diversity of sources which may influence boat microbial communities. We investigated the impact of dock, air, and water microbial communities on the hull, transom, and bilge microbial communities over the span of 11 days. Methods and results: Using source tracking software, we investigated the extent to wh...

Marine microbial communities are a vital component of global carbon cycling, and numerous studies have shown that populations of petroleum-degrading bacteria are ubiquitous in the oceans. Few studies have attempted to distinguish all of the taxa that might contribute to petroleum biodegradation (including, e.g., heterotrophic and nondesignated micr...

The environmental surveys following the 2010 Deepwater Horizon (DWH) spill identified a variety of hydrocarbon-degrading microorganisms, and laboratory studies with field-collected water samples then demonstrated faster-than-expected hydrocarbon biodegradation rates at 5°C. Knowledge about microbial community composition, diversity, and functional...

We conducted a global characterization of the microbial communities of shipping ports to serve as a novel system to investigate microbial biogeography. The community structures of port microbes from marine and freshwater habitats house relatively similar phyla, despite spanning large spatial scales. As part of this project, we collected 1,218 surfa...

We conducted a global characterization of the microbial communities of shipping ports to serve as a novel system to investigate microbial biogeography. The community structures of port microbes from marine and freshwater habitats house relatively similar phyla, despite spanning large spatial scales. As part of this project, we collected 1,218 surfa...

In the past, ballast water has been a key vector in the ship-mediated dispersal of invasive species. Here, we evaluate the potential for port microorganisms to enter and colonize the hull and bilge water of ships. Due to the small size and ubiquitous nature of bacteria, they also have the potential to be spread through hull fouling and bilge water...

Biocides used in unconventional oil and gas (UOG) practices, such as hydraulic fracturing, control microbial growth. Unwanted microbial growth can cause gas souring, pipeline clogging, and microbial-induced corrosion of equipment and transportation pipes. However, optimizing biocide use has not been a priority. Moreover, biocide efficacy has been q...

Production of unconventional oil and gas continues to rise, but the effects of high-density hydraulic fracturing (HF) activity near aquatic ecosystems are not fully understood. A commonly used biocide in HF, 2,2-dibromo-3-nitrilopropionamide (DBNPA), was studied in microcosms of HF-impacted vs. HF-unimpacted surface water streams to (1) compare the...

The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural a...

The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural a...

Many freshwater environments experience dramatic seasonal changes with some systems remaining ice-covered for most of the winter. Freshwater systems are also highly sensitive to environmental change. However, little is known about changes in microbial abundance and community composition during lake ice formation and times of persistent ice cover. T...

Microbial adaptation to extreme conditions takes many forms, including specialized metabolism which may be crucial to survival in adverse conditions. Here, we analyze the diversity and environmental importance of systems allowing microbial carbon monoxide (CO) metabolism. CO is a toxic gas that can poison most organisms because of its tight binding...

[This corrects the article on p. 147 in vol. 2, PMID: 21808633.].

Clay-based flocculation techniques have been developed to mitigate harmful algal blooms; however, the potential ecological impacts on the microbial community are poorly understood. In this study, chemical measurements were combined with 16S rRNA sequencing to characterize the microbial community response to different flocculation techniques, includ...

Nine important hydrocarbon (oil) basins where offshore petroleum leases have been licensed are compared. These nine basins (Gulf of Mexico, Eastern Mediterranean’s Nile Deep-Sea Fan, Central Mediterranean and the Sirte Basin, North Sea, Caspian Sea, Angola, Trinidad and Tobago, Great Australian Bight, and Brazil’s Amazonian Deep-Sea Basin) are geog...

Deep marine oil spills like the Deepwater Horizon (DWH) in the Gulf of Mexico have the potential to drastically impact marine systems. Crude oil contamination in marine systems remains a concern, especially for countries around the Mediterranean Sea with off shore oil production. The goal of this study was to investigate the response of indigenous...

The nitrogen cycle in the marine environment is strongly affected by ammonia oxidizing Thaumarchaeota. In some marine settings Thaumarchaeotes can comprise a large % of the prokaryotic population. To better understand the biogeographic patterns of Thaumarchaeotes, we sought to investigate differences in their abundance and phylogenetic diversity be...

To better understand the impacts of Corexit 9500 on the structure and activity levels of hydrocarbon-degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at 5 and 25°C using both DNA and RNA extracts as the sequencing templates. Oil biodegradation patterns in both 5 and 25°...

With the rapid advances in sequencing technology, the cost of sequencing has dramatically dropped and the scale of sequencing projects has increased accordingly. This has provided the opportunity for the routine use of sequencing techniques in the monitoring of environmental microbes. While metagenomic applications have been routinely applied to be...

Many studies have shown that microbes, which share nearly identical 16S rRNA genes, can have highly divergent genomes. Microbes from distinct parts of the ocean also exhibit biogeographic patterning. Here we seek to better understand how certain microbes from the same species have adapted for growth under local conditions. The phenotypic and genomi...

Many microbial ecology experiments use sequencing data to measure a community's response to an experimental treatment. In a common experimental design, two units, one control and one experimental, are sampled before and after the treatment is applied to the experimental unit. The four resulting samples contain information about the dynamics of orga...

Hydraulic fracturing (HF) in the process of injecting a cocktail of chemicals, sand, and water into an underground rock formation to create fractures and release natural gas. Commonly, biocides are added to prevent biofouling of equipment and prevent microbial growth during gas extraction and gas souring. During extraction some of the injected wate...

Hydrocarbon production from hydraulic fracturing of gas shale in the US has skyrocketed and is projected to keep growing. This water intensive drilling process creates toxic wastewater without an efficient disposal method. Because this method involves projecting fluid 1-3 km deep into the Earth, it is likely that microbial communities adapted to th...

Hydrocarbon production from hydraulic fracturing of gas shale in the US has skyrocketed and is projected to keep growing. This water intensive drilling process creates toxic wastewater without an efficient disposal method. Because this method involves projecting fluid 1-3 km deep into the Earth, it is likely that microbial communities adapted to th...

Hydrocarbon production from hydraulic fracturing of gas shale in the US has skyrocketed and is projected to keep growing. This water intensive drilling process creates toxic wastewater without an efficient disposal method. Because this method involves projecting fluid 1-3 km deep into the Earth, it is likely that microbial communities adapted to th...

The 32 closely related Pseudoalteromonas spp. we isolated were found in different environments not previously sampled throughout the world’s deep oceans. The isolates’ 16S rRNA gene sequences were more than 99% similar, while the genomic makeup was less than 99% similar. The environmental parameters of these locations vary greatly and little is kno...

Many studies have shown that microbial communities can play an important role in oil spill clean up. However, very limited information is available on the oil degradation potential and microbial community response to crude oil contamination in deep oceans. Therefore, we investigated the response of microbial communities to crude oil and dispersant...

Many studies have shown that microbial communities can play an important role in oil spill clean up. However, very limited information is available on the oil degradation potential and microbial community response to crude oil contamination in deep oceans. Therefore, we investigated the response of microbial communities to crude oil in various deep...

Hydraulic fracturing (HF) has grown very fast in the past several years, with an estimated 700% increase since 2007. During the process of HF a cocktail of chemicals, sand, and water are injected into a shale formation to create fractures, which enable release of gas. In most HF operations, biocides are added to prevent biofouling of equipment and...

Many studies have shown that microbial communities can play an important role in oil spill clean up. However, very limited information is available on the oil degradation potential and microbial community response to crude oil contamination in deep oceans. Therefore, we investigated the response of microbial communities to crude oil in various deep...

Hydrocarbon production from hydraulic fracturing of gas shale in the US has skyrocketed and is projected to keep growing. This water intensive drilling process creates toxic wastewater without an efficient disposal method. Because this method involves projecting fluid 1-3 km deep into the Earth, it is likely that microbial communities adapted to th...

Hydraulic fracturing (HF) in the process of injecting a cocktail of chemicals, sand, and water into an underground rock formation to create fractures and release natural gas. Commonly, biocides are added to prevent biofouling of equipment and prevent microbial growth during gas extraction and gas souring. During extraction some of the injected wate...

Lipid/DNA co-extraction from one sample is attractive in limiting biases associated with microbial community analysis from separate extractions. We sought to enhance established co-extraction methods and use high-throughput 16S rRNA sequencing to identify preferentially extracted taxa from co-extracted DNA. Co-extraction results in low DNA yields a...

Biological sensors can be engineered to measure a wide range of environmental conditions. Here we show that statistical analysis of DNA from natural microbial communities can be used to accurately identify environmental contaminants, including uranium and nitrate at a nuclear waste site. In addition to contamination, sequence data from the 16S rRNA...

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to exam...

The Caspian Sea is heavily polluted due to industrial and agricultural effluents as well as extraction of oil and gas reserves. Microbial communities can influence the fate of contaminants and nutrients. However, insight into the microbial ecology of the Caspian Sea significantly lags behind other marine systems. Here we describe microbial biomass,...

Microbes are extremely diverse and capable of catalyzing many functions. Currently, microbial species are defined though characterization of the microbe’s metabolism and through sequencing of 16S rRNA. Recent studies suggest that microbes classified as the same species through 16S rRNA sequencing may demonstrate high genetic diversity. The goal of...

16S rRNA sequencing is routinely used to investigate the diversity of prokaryotes in environmental settings. Evidence suggests that microbes with nearly identical 16S rRNA genes can have genotypic heterogeneity. To better understand the diversity within a single microbial species, we characterized the phenotypic and genomic heterogeneity of three s...

Microbes are essential in the cycling of nutrients within the environment. Since the discovery of ammonia-oxidizing archaea (AOA), it is now understood that Thaumarchaeota may play an important role in the nitrogen cycle within marine environments. AOA are mainly responsible for the nitrogen cycle's first step, which is oxidation of ammonia to nitr...

Hydrocarbon production from hydraulic fracturing of gas shale in the US has skyrocketed recently and is projected to keep growing. With the increase of this unconventional drilling method, concerns have been proposed about environmental safety and dangers to human health. Because this method involves injecting fluid between 1-3 km deep into the Ear...

We characterized the groundwater bacterial communities of 93 wells from the Oak Ridge Integrated Field-scale Research Challenge site with two habitat fractions presenting different species dispersal traits: free-living (0.22-um filter) and particle-associated (10-um filter). Along the multiple environmental gradients (including pH and contaminants)...

Hydraulic fracturing is growing exponentially, causing a 702% increase in shale gas production in the U.S. since 2007. This process is water intensive, requiring between 3.3 to 27m3 of water per million cubic meters of gas extracted. As this process keeps growing, and water scarcity issues continue to arise throughout the world, questions keep risi...

The microbial transformation of allochthonous terrestrial organic matter, particularly recalcitrant aromatic lignin, is a significant but poorly understood phenomenon in the marine ecosystem. The genetic basis of microbial lignin degradation is of high interest because of its potential application to lignocellulosic biofuel and lignin valorization....

Laboratory bioreactors have long been used for investigating the characteristics of a microorganism or simple synthetic community. However, for studying natural or in-situ microbial communities, discontinuous “snapshot in time” sampling has mainly occurred. In this study an in-field bioreactor system was developed to temporally monitor and manipula...

Treatment and reuse of hydraulic fracturing flowback water is the best alternative to handle the enormous volume of wastewater produced. Intrinsic bioremediation and bioaugmentation are efficient ways to treat the high salinity and chemical content of this water. The microbial community in flowback water can provide an insight into what facilitates...

Microbes are the most prevalent living organisms in the world. They are found in almost every environment on earth, and are essential for the cycling of nutrients, such as carbon and nitrogen, in the environment. The nitrogen cycle is essential to life as it converts nitrogen into forms that can be used as nutrients for life. While much is known ab...

Oil spills such as the Deepwater Horizon Oil spill in the Gulf of Mexico have the potential to drastically impact marine systems. However, offshore oil and gas prospecting is expanding with increased demand for petroleum. As a result, the risk of oil contamination in the marine system remains a huge concern to the public and governments around the...

Crude oil contamination in the ocean from oil spills becomes a huge concern to the public and governments. Very limited information is available on the oil degradation potential and microbial community response to crude oil contamination in deep oceans. In this study, we investigated the response of microbial communities to crude oil in various dee...

16S rRNA gene sequencing is routinely used to identify the taxonomy of prokaryotes. Recent evidence suggests that microbes with nearly identical 16S rRNA genes can have substantial genotypic heterogeneity. To better understand the diversity within a single microbial species, we set out to characterize the phenotypic and genomic diversity of three s...

The microbial transformation of allochthonous terrestrial organic matter, particularly recalcitrant aromatic lignin, is a significant but poorly understood phenomenon in the marine ecosystem. We aim to elucidate the diversity and metabolic potential of a marine bacterial community subsisting on lignin. Seawater from the oxic and ultra-oligotrophic...

The Mediterranean Sea is home to a diverse community of heterotrophic microbes responsible for cycling much of the organic carbon that enters its waters. The subset of those organisms that utilize macromolecules produce extracellular enzymes as a means of carbon degradation. However, this hydrolytic community is poorly characterized at water column...