Algal polysaccharides for 3D printing: A review.

Algae hold particular promise as a feedstock for biomaterials, as they are capable of producing a wide variety of polymers with the properties required for 3D printing. However, the use of algal polymers has been limited to alginate, agar, carrageenan, and ulvan extracted from seaweeds. Diverse algal taxa beyond seaweeds have yet to be explored. In this comprehensive review, we discuss available algal biomaterials, their properties, and emerging applications in 3D printing techniques. We also identify elite algal strains to be used in 3D printing and comment on both advantages and limitations of algal biomass as a printing material. Global 3D printing market trends and material demands are also critically analyzed. Finally, the future prospects, opportunities, and challenges for using algal polymers in 3D printing market for a sustainable economy are discussed. We hope this review will provide a foundation for exploring the 3D printable biomaterials from algae.

Data for designing microalgal consortia for higher yield.

The data reported here were directly used in the research article entitled "A novel approach to build algal consortia for sustainable biomass production (Mandal and Corcoran, 2022)". Data were collected to (1) generate microalgal consortia through a functional diversity approach and (2) test generated consortia against monocultures. Algal trait data (i.e., growth rate, carrying capacity) related to light, temperature, and salinity were collected in thirteen Nannochloropsis and Microchloropsis strains grown under different resource levels/conditions. Trait values were used in an in-silico method to calculate the functional diversity index (FDi) in all possible consortia (8178 combinations). Two metrics, the Net Biodiversity Effect (NBE) and Overyielding (OY), were used to assess the utility of this functional dispersion approach in consortia building for algal production.

Bioprospecting Indigenous Marine Microalgae for Polyunsaturated Fatty Acids Under Different Media Conditions.

Marine microalgae produce a number of valuable compounds that have significant roles in the pharmaceutical, biomedical, nutraceutical, and food industries. Although there are numerous microalgal germplasms available in the marine ecosystem, only a small number of strains have been recognized for their commercial potential. In this study, several indigenous microalgal strains were isolated from the coast of the Arabian Sea for exploring the presence and production of high-value compounds such as polyunsaturated fatty acids (PUFAs). PUFAs are essential fatty acids with multiple health benefits. Based on their high PUFA content, two isolated strains were identified by ITS sequencing and selected for further studies to enhance PUFAs. From molecular analysis, it was found both the strains were green microalgae: one of them was a Chlorella sp., while the other was a Planophila sp. The two isolated strains, together with a control strain known for yielding high levels of PUFAs, Nannochloropsis oculata, were grown in three different nutrient media for PUFA augmentation. The relative content of α-linolenic acid (ALA) as a percentage of total fatty acids reached a maximum of 50, 36, and 50%, respectively, in Chlorella sp., Planophila sp., and N. oculata. To the best of our knowledge, this is the first study in exploring fatty acids in Planophila sp. The obtained results showed a higher PUFA content, particularly α-linolenic acid at low nutrients in media.

Comparing Trace Element Bioaccumulation and Depuration in Snails and Mayfly Nymphs at a Coal Ash-Contaminated Site.

We examined the bioaccumulation of essential (Cu, Fe, Se, and Zn) and nonessential (As and Hg) trace elements in 2 aquatic invertebrate species (adult snails and mayfly nymphs) with different feeding habits at the site of a coal ash spill. Differences in food web pathway, exposure concentrations, and biological processing affected bioaccumulation patterns in these species. Mayflies had higher body burdens, but snails had higher retention of most elements studied. Environ Toxicol Chem 2020;39:2437-2449. © 2020 SETAC.

Heterogeneity in Nitrogen Sources Enhances Productivity and Nutrient Use Efficiency in Algal Polycultures.

Algae hold much promise as a potential feedstock for biofuels and other products, but scaling up biomass production remains challenging. We hypothesized that multispecies assemblages, or polycultures, could improve crop yield when grown in media with mixed nitrogen sources, as found in wastewater. We grew mono- and poly- cultures of algae in four distinct growth media that differed in the form (i.e., nitrate, ammonium, urea, plus a mixture of all three) but not the concentration of nitrogen. We found that mean biomass productivity was positively correlated with algal species richness, and that this relationship was strongest in mixed nitrogen media (on average 88% greater biomass production in 5-species polycultures than in monocultures in mixed nitrogen treatment). We also found that the relationship between nutrient use efficiency and species richness was positive across nitrogen treatments, but greatest in mixed nitrogen media. While polycultures outperformed the most productive monoculture only 0-14% of the time in this experiment, they outperformed the average monoculture 26-52% of the time. Our results suggest that algal polycultures have the potential to be highly productive, and can be effective in recycling nutrients and treating wastewater, offering a sustainable and cost-effective solution for biofuel production.

Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production.

Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pretreatments ofbiomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.

Industrial-strength ecology: trade-offs and opportunities in algal biofuel production.

Microalgae represent one of the most promising groups of candidate organisms for replacing fossil fuels with contemporary primary production as a renewable source of energy. Algae can produce many times more biomass per unit area than terrestrial crop plants, easing the competing demands for land with food crops and native ecosystems. However, several aspects of algal biology present unique challenges to the industrial-scale aquaculture of photosynthetic microorganisms. These include high susceptibility to invading aquatic consumers and weeds, as well as prodigious requirements for nutrients that may compete with the fertiliser demands of other crops. Most research on algal biofuel technologies approaches these problems from a cellular or genetic perspective, attempting either to engineer or select algal strains with particular traits. However, inherent functional trade-offs may limit the capacity of genetic selection or synthetic biology to simultaneously optimise multiple functional traits for biofuel productivity and resilience. We argue that a community engineering approach that manages microalgal diversity, species composition and environmental conditions may lead to more robust and productive biofuel ecosystems. We review evidence for trade-offs, challenges and opportunities in algal biofuel cultivation with a goal of guiding research towards intensifying bioenergy production using established principles of community and ecosystem ecology.

Biodiesel production by the green microalga Scenedesmus obliquus in a recirculatory aquaculture system.

Biodiesel production was examined with Scenedesmus obliquus in a recirculatory aquaculture system with fish pond discharge and poultry litter to couple with waste treatment. Lipid productivity of 14,400 liter ha(-1) year(-1) was projected with 11 cultivation cycles per year. The fuel properties of the biodiesel produced adhered to Indian and international standards.

Waste utilization and biodiesel production by the green microalga Scenedesmus obliquus.

Scenedesmus obliquus was cultivated in three types of waste discharges to couple waste treatment with biodiesel production. The lipid pool accumulation was boosted to 1.0 g liter(-1) against 0.1 g liter(-1) for the control. The waste-grown S. obliquus showed an increase in the content of the saturated fatty acid pool, which is desirable for good-quality biodiesel.

Microalga Scenedesmus obliquus as a potential source for biodiesel production.

Biodiesel from microalgae seems to be the only renewable biofuel that has the potential to completely replace the petroleum-derived transport fuels. Therefore, improving lipid content of microalgal strains could be a cost-effective second generation feedstock for biodiesel production. Lipid accumulation in Scenedesmus obliquus was studied under various culture conditions. The most significant increase in lipid reached 43% of dry cell weight (dcw), which was recorded under N-deficiency (against 12.7% under control condition). Under P-deficiency and thiosulphate supplementation the lipid content also increased up to 30% (dcw). Application of response surface methodology in combination with central composite rotary design (CCRD) resulted in a lipid yield of 61.3% (against 58.3% obtained experimentally) at 0.04, 0.03, and 1.0 g l(-1) of nitrate, phosphate, and sodium thiosulphate, respectively for time culture of 8 days. Scenedesmus cells pre-grown in glucose (1.5%)-supplemented N 11 medium when subjected to the above optimized condition, the lipid accumulation was boosted up to 2.16 g l(-1), the value approximately 40-fold higher with respect to the control condition. The presence of palmitate and oleate as the major constituents makes S. obliquus biomass a suitable feedstock for biodiesel production.