Navid R Moheimani

• BSc, MSc, PhD
• Senior Lecturer at Murdoch University

The cement industry is a major contributor to global CO 2 emissions, necessitating sustainable alternatives. Biocement production using microalgae-derived calcium carbonate (CaCO 3) offers a promising solution. Coc-colithophores, a group of calcifying microalgae, naturally produce CaCO 3 , which can be extracted and utilized in biocement production...

Microalgae could serve as an improved source of bioavailable heme for the treatment of chronic anemia in humans and animals, and/or be used as an additive for plant-based protein products to provide a ‘meaty’ taste. Unfortunately, ‘standard’ spectrophotometric assays developed for heme-rich samples, particularly meat and blood samples, are not viab...

Featured Application This study explores the feasibility of using anaerobically digested food effluent as a sustainable and cost-effective alternative nutrient source for large-scale Spirulina cultivation, reducing production costs while improving biomass productivity in outdoor wastewater treatment systems. Abstract The cultivation of Arthrospira...

Currently, there is a global interest in the production of marine natural products. Naturally occurring macroalgae can be a potentially viable source of generating various products such as dyes and carbohydrates. Hence, in this study, the potential of extracting natural solvent-based dyes of Sargassum sp., Gracilaria sp., and Enteromorpha sp. was e...

Anaerobic digestate animal effluent (ADAE) contains high N and P nutrients which need to be treated. In this study, an integrated process was proposed using a microalgae consortium of Chlorella and Scenedesmus. The system was designed for 71 m3/d (medium-sized) and 355 m3/d (large-sized) animals of ADAE. Process simulation estimated to produce 83–4...

The contributions of the cement industry to climate change and global warming are important global issues that require immediate attention. The utilization of coccoliths produced by coccolithophores in biocement production is a promising solution. In this study, the potential to enhance the production of Chrysotila carterae coccoliths by optimizing...

The wastewater produced from the meat-processing industry is a rich source of nutrients which can be recovered using microalgae. This study assesses the potential of microalgae cultivation on abattoir wastewater based on its nutrient removal capacity from wastewater, biomass production and greenhouse gas (GHG) emission savings potential. Designing...

Reverse osmosis is currently the most promising method for addressing freshwater scarcity in numerous nations, enabling the production of drinkable water for human consumption. This process, however, generates a byproduct stream, known as desalination concentrate (DC), that is enriched with high concentrations of salts such as Na⁺ and Cl⁻, moderate...

Membrane fouling is a major challenge which limits the sustainable application of membrane filtration-based microalgal harvesting at industrial level. Membrane fouling leads to increased operational and maintenance costs and represents a major obstacle to microalgal downstream processing. Nano-clays are promising naturally occurring nanoparticles i...

The use of microalgae for nutrient recovery from wastewater and subsequent conversion of the harvested biomass into fertilizers offers a sustainable approach towards creating a circular economy. Nonetheless, the process of drying the harvested microalgae represents an additional cost, and its impact on soil nutrient cycling compared to wet algal bi...

Microalgae can treat waste streams containing elevated levels of organic carbon and nitrogen. This process can be economically attractive if high value products are created simultaneously from the relatively low-cost waste stream. Co-production of two high value microalgal products, phycocyanin and polyhydroxybutyrate (PHB), was investigated using...

Microalgal technology is still economically unattractive due to the high cost associated with microalgal cultivation and biomass recovery from conventional suspension cultures. Biofilm-based cultivation is a promising alternative for higher biomass yield and cheap/easy biomass harvesting opportunities. Additionally, using anaerobic digestate food e...

Utilisation of microalgae to extract nutrients from the effluent of anaerobic digestion of food waste is an emerging technology. A by-product of this process is the microalgal biomass which has potential to be used as an organic bio-fertilizer. However, microalgal biomass are rapidly mineralized when applied to soil which may result in N loss. One...

Here, we evaluated the effect of culture depth on the growth and nutrient removal rate of Scenedesmus sp. grown in anaerobically digested abattoir effluent (ADAE) and cultivated semi-continuously in raceway ponds at depths of 14 cm, 17 cm, 20 cm, and 23 cm during Austral winter and summer. Culture medium pH was kept constant at pH 6.5 for all treat...

Hydrothermal carbonization is an environmentally benign approach to producing hydrochar from wet biomass owing to no need for a pre-drying process. This study aims to examine the effect of temperature and time on hydrochar characteristics from the hydrothermal carbonization of Ulva lactuca. The hydrothermal carbonization was performed using a batch...

Sufficient and reliable long-term field data on the growth, productivity and nutrient removal rates of microalgal based wastewater treatment system is essential to validate its overall techno-economic feasibility. Here, we investigated the semi-continuous microalgal cultivation of Scenedesmus sp. in anaerobically digested abattoir effluent (ADAE) f...

Dunaliella salina microalgae is a third-generation feedstock that is both thermophilic and halophilic and can be used to produce nutritious food supplements such as β-carotene. Although several techno-economic studies have been carried out to produce the pigment, most of them considered traditional synthetic chemicals such as hexane, acetone, and p...

Biodiesel is a promising alternative to reduce the dependency on fossil fuels. However, biodiesel's cost is still higher than its petroleum counterpart, hence its production process must be modified to make it economically viable. Microalgae are an alternative feedstock to replace agricultural crops for biodiesel production, and offer several advan...

Microalgae are promising renewable feedstocks for producing biodiesel as an alternative to conventional diesel. However, the major bottleneck in microalgal biodiesel production is a rather high energy consumption and production costs, which limit the economic feasibility and industrial commercialization. In microalgal downstream processing, biomass...

This study evaluated a novel two-step process for biological lixiviant generation to facilitate base metals leaching from waste printed circuit boards (PCBs). In the first step, crushed waste sulfur pastilles, a by-product of the petroleum industry, were biologically oxidised to produce biogenic H2SO4. The acidified effluent containing biogenic H2S...

Outdoor studies were conducted on microalgae cultures in two raceway ponds (kept in constant motion with either jet or paddlewheel) with a flatbed to treat anaerobic digestion piggery effluent and to observe the characteristics of turbulence on microalgal mixing and growth. Acoustic Doppler Velocimeters (ADV) were deployed to record the instantaneo...

Diversion of food waste from landfill through anaerobic digestion is a sustainable form of energy production (biogas) and the waste effluent (digestate) can be utilised as nutrient supply for microalgae cultivation. However, digestate has very high nutrient concentrations and is highly turbid, making it difficult to utilize as a nutrient source wit...

Biomass-derived energy is gaining more attention due to environmental issues and increasing energy demand. To ensure the sustainability of fossil energy substitution using biomass, diversification of sources, including marine organisms, is vital. Among various types of marine biomass discussed in the literature, the utilization of green algae Ulva...

The study of a stir cast Al356-Nb2O5)P composite immersed in third-generation microalgal-derived biodiesel blends with enhanced plasma electrolyte oxidation surface modification revealed the corrosion susceptibility and possible by-product formation. The effect of (oxide)P reinforcement and mixed-oxide surface coatings were studied separately and c...

This study investigated the possibility of enhancing the biomass productivity and nutrient removal of microalgae grown in raceway ponds through temperature regulation. Scenedesmus sp. grown in anaerobically digested abattoir effluent (ADAE) was cultivated outdoor in eight raceway ponds. Seven ponds were subjected to different temperature regulation...

Membrane technology has emerged as a possible solution to the challenge of biomass recovery facing microalgal industry. However, fouling phenomenon hinders the development of membrane processes. In this regard, different fouling mitigation strategies have been developed, among which membrane surface modification is one of the most promising approac...

Accurate and detailed reporting of methods is essential for scientific progress, yet it is widely accepted that authors across all scientific fields tend to provide insufficient methods detail. Given the recent proliferation of automated and semi-automated technologies for data collection, to address this widespread issue the details needed for int...

Microalgae have the potential to be an excellent source of sustainable and renewable biofuel. However, different issues surrounding their economic viability and upscale application need to be resolved. Microalgal dewatering requires substantial energy to concentrate the highly dilute microalgal culture and is considered a major bottleneck that limi...

Botryococcus braunii CCAP 807/2 has been studied intensively for biofuel production due to its high hydrocarbon content. This strain is also capable of producing high value carotenoids. The aim of the study was to analyse the carotenoid production of B.braunii 807/2 under different growing conditions, first, by using different media and light inten...

The purpose of this study is to develop an initial computational model to evaluate the techno-economic viability of high-value and secondary resources from microalgae. The isolation of high-value metabolites is the driving product to improve the overall economics. This approach will allow marketing secondary compounds at more competitive rates for...

The dye‐sensitized solar cells (DSSCs) can be effectively improved and stabilized by outstanding electrical and morphological characteristics of TiO2 nanofibres combined with bio‐calcium doping. The pristine and bio‐Ca‐doped TiO2 nanofibres were fabricated using a cost‐effective electrospinning technique. Biocompatible calcium carbonate nanoparticl...

Indonesia is the second world’s major macroalgae producer after China, contributing to 28% of the global macroalgae production. Indonesia increased its macroalgae farming output from less than 4 million tons in 2010 to over 9.9 million tons in 2019. It is expected to continue rising to 13 million tons by 2024. The contribution of macroalgal product...

Fire extinguishers are used to contain the imminent risk posed by fire globally. Suitable disposal and utilization of fire extinguisher powder (FEP) waste have developed into a significant challenge due to high nitrogen and phosphorus content. Harnessing the waste as a secondary resource for integrated waste-to-profit enterprises, such as microalga...

The increase in the human population causes an increase in the demand for nutritional supplies and energy resources. Thus, the novel, natural, and renewable resources became of great interest. Here comes the optimistic role of bioprospecting as a promising tool to isolate novel and interesting molecules and microorganisms from the marine environmen...

The global seaweed market is currently valued at USD $11 billion annually and utilizes about 29 million tonnes of seaweed (dry weight) for a variety of applications (Ferdouse et al., Globefish Res Programme 124:I, 2018). By 2025 the global market is estimated to reach USD $30.2 billion dollars (Bloomberg, 2020). The current Australian seaweed marke...

Ulva Lactuca is a fast-growing algae that can be utilized as a bioenergy source. However, the direct utilization of U. lactuca for energy applications still remains challenging due to its high moisture and inorganics content. Therefore, thermochemical processing such as slow pyrolysis to produce valuable added products, namely bio-oil and biochar,...

This study investigated the outdoor cultivation of two local microalgae species (Chlorella sp. and Scenedesmus sp.) in raw anaerobically digested abattoir effluent (ADAE) which were subjected to both continuous (24 h) and daytime only (12 h) paddle wheel mixing. The goal of this study was to identify the most efficient microalgae species and mixing...

Dunaliella salina is well-known for its ability to accumulate high amounts of carotenoids when cultivated under high salinity and high irradiance. However, as with all microalgae, cultivation processes are expensive when synthetic fertilizers are used for cultivation. In this study, we assessed the feasibility of utilizing anaerobic digestate of fo...

Dewatering constitutes a major drawback in terms of cost and energy required to concentrate a highly diluted microalgal culture. This has hampered the economic viability of microalgal products. To this end, several technologies have been developed for harvesting microalgal biomass. Membrane technology emerges as one of the preferred harvesting and...

Microalgal cultivation is currently stifled by various constraints. In winter, additional losses are incurred due to lower productivities. Here, effects of medium recycling to conserve water use, paddle wheel mixing duration to reduce power consumption and culture depth on growth of Dunaliella salina (MUR 8) cultivated in raceway ponds during the A...

Biofuels, like any high-affinity chemical mixtures; can cause tribological effects at interfaces with metallics (ferrous-nonferrous) and non-metallics due to medium assisted activation of corrosion by unsaturated components. The damages; corrosion and tribological effects on surfaces (abrasive wears and edge/cosmetic corrosion), also include contam...

This study investigated the use of an innovative Proportional Integral (PI) + dead-zone control strategy to improve pH control and to overcome the negative environmental impact associated with the currently employed on/off pH control schemes for microalgae cultivation. Scenedesmus sp. grown in anaerobically digested abattoir effluent (ADAE) was use...

Electronic waste is a growing waste stream globally. With 54.6 million tons generated in 2019 worldwide and with an estimated value of USD 57 billion, it is often referred to as an urban mine. Printed circuit boards (PCBs) are a major component of electronic waste and are increasingly considered as a secondary resource for value recovery due to the...

Microalgae offer a cost-effective option for wastewater treatment due to their natural ability to uptake and assimilate various forms of nutrients for the production of valuable biomass. Here, we assessed the potential of Scenedesmus sp. culture for treating anaerobically digested abattoir effluent (ADAE). Scenedesmus sp. was cultured at different...

Hydrogen, one of the green energy resources, has attracted much attention since it can be produced from biomass with zero net CO2 emissions. Supercritical water gasification (SCWG) is an emerging technology for hydrogen production from macroalgae. It enables the elimination of the costly feedstock-drying step. However, a comprehensive review of hyd...

Turbidity is a problem with microalgal growth in anaerobic digestate (AD) due to increased light attenuation, consequently resulting in reduced biomass yields. In this study, Chlorella sp. MUR 268 was cultivated in semi-continuous mode using turbid, high NH3 concentrated (160 ± 10 mg L−1) AD of food waste, reaching biomass yield of 4.319 ± 0.18 g L...

Anaerobically digested food effluent (or liquefied food waste) was diluted with synthetic brine to prepare new media for cultivating Chlorella vulgaris. The media were prepared from different ratios of liquified food waste and synthetic brine. These ratios were 1:1, 1:2, and 1:3 and the media were named as CM2, CM3, and CM4, respectively. Johnson’s...

Electronic e-waste (e-waste) is a growing problem worldwide. In 2019, total global production reached 53.6 million tons, and is estimated to increase to 74.7 million tons by 2030. This rapid increase is largely fuelled by higher consumption rates of electrical and electronic goods, shorter life cycles and fewer repair options. E-waste is classed as...

Within the biorefinery concept, microalgal cultivation has potential as one component of the wastewater treatment toolkit for anaerobic digestates. Recovering nutrients from digestate such as anaerobic digestate of piggery effluent, has been well demonstrated with Scenedesmus sp. and Chlorella sp. in mixed cultures. Less understood during microalga...

Monochromatic blue and red wavelengths are more efficient for light to algal biomass conversion than full-spectrum sunlight. In this study, monochromatic light filters were used to down-regulate natural sunlight to blue (400 – 520 nm) and red (600 – 700 nm) wavelengths to enhance biomass productivity of Dunaliella salina in outdoor raceway ponds. G...

Microalgae dewatering is a major bottleneck for biomass production in a large-scale microalgal production system which accounts for 20–60% of production cost. In this study, three dewatering systems of electrocoagulation, flocculation, and pH-induced flocculation were evaluated for microalgal consortium grown in anaerobically digested abattoir effl...

Co-sensitization is an effective strategy to achieve panchromatic light-harvesting and to enhance dye-sensitized solar cell performance. In this work, the potential of the extracted natural dyes from Malva verticillata and Syzygium cumini was evaluated as mono and co-sensitizers in DSSCs. The UV-Vis absorption spectra revealed that the combination...

Untreated as well as partially treated anaerobic digestate abattoir effluent (ADAE) were used for the cultivation of Arthrospira platensis in this study. The effect of CO2 addition on the biomass productivity, nutrient removal efficiency and biochemical composition were also investigated. Arthrospira platensis exhibited significant improved growth...

The Arabian Gulf is one of the most adversely affected marine environments worldwide, which results from combined pollution drivers including climate change, oil and gas activities, and coastal anthropogenic disturbances. Desalination activities are one of the major marine pollution drivers regionally and internationally. Arabian Gulf countries rep...

Anaerobic digestion is a suitable method for treating organic wastes and generating biogas. This biogas contains significant amount of CO2 and some other contaminants. The coupling of wastewater treatment with biogas purification using saline microalgae could effectively upgrade biogas (through photosynthetic CO2 fixation) and concurrently remove n...

The successful cultivation of microalgae in wastewater establishes a waste to profit scenario as it combines treatment of a waste stream with production of valuable end-products. Here, growth and nutrient removal efficiency of three different locally isolated microalgal cultures (Chlorella sp., Scenedesmus sp., and a mixed consortium) cultivated in...

Anthropogenic lead (Pb) contamination resulting from the rapid growth of industrialization in coastal environments poses significant challenges. In this study, we report a novel approach utilising the large benthic foraminifera Amphisorus hemprichii as a biogeochemical archive for monitoring Pb pollution in tropical to warm-temperate coastal waters...

Solar cultivation of microalgae in photobioreactors is a valuable bioprocess for the sustainable production of commercially useful metabolites. However, the conventional culture temperature control method in solar closed photobioreactors of evaporative cooling is neither economical nor sustainable. In this study, a novel spectrally selective, insul...

Anaerobic digestate of food waste as a waste product of anaerobic digestion contains a significant amount of nutrients making its direct disposal prohibitive due to environmental regulations. However, the nutrients in this waste are a valuable feedstock for waste-to-product endeavours such as microalgae cultivation coupled to the treatment of the d...

Increasing microalgal biomass productivity and enhancing nutrient removal rates are critical when growing microalgae in wastewater. In most cases, the effluents such as anaerobically digested food effluent (ADFE) are very turbid. Using such effluents as a medium for an algal culture would leave the culture with high turbidity resulting in photo-lim...

Anaerobically digested food waste (ADF) is a waste effluent produced from anaerobic digestion of food wastes. It is difficult to treat but also holds high potential for valorization. Microalgae cultivation is a promising path for its treatment and valorization. However, ADF is very turbid and has toxic concentration of ammonia nitrogen (NH3- N) (up...

The need for thermal regulation in microalgal photobioreactors is a significant impediment to their large-scale adoption. The energy costs associated with thermal regulation alone can easily result in a negative energy balance. Self-sustaining photovoltaic powered photobioreactors that do not require cooling systems provide an opportunity to maximi...

Nannochloropsis is an algal species with a worldwide biotechnological interest. To improve biomass and lipid productivities of this alga while grown in outdoor paddle-wheel driven raceway ponds, different harvesting frequencies were implemented. Four harvesting frequencies (10% harvested, five days (R10F5), 20% harvested, three days (R20F3), 30% ha...

The operation of solar microalgal photobioreactors requires sufficient cooling and heating to maintain reliable high productivity year-round. These operations are energy-intensive and expensive. Growth characteristics and phycocyanin production of Arthrospira platensis were investigated during the austral winter using a thermally-insulated photobio...

Microalgae cultivation on wastewater augments the conversion of a waste stream into a profitable end-product, thus, establishing a circular economy. In this study, we successfully isolated and established the growth of a local microalga Chlorella sp. (Trebouxiophyceae) on raw anaerobically digested abattoir effluent (ADAE). The effect of CO2 additi...

The production of oil from microalgae is a process with a long way to go before reaching commercial viability. High costs associated with harvesting and solvent extraction make it difficult to compete with fossil fuel. The in-situ, non-destructive, repetitive extraction of lipids from Botryococcus braunii (milking) offers an alternative to the conv...