Lipid-extracted algae as a source of biomaterials for algae biorefineries

Alahmari A, A. Alqabbani A, Aldayel AM. Exploring the landscape of Lipid Nanoparticles (LNPs): A comprehensive review of LNPs types and biological sources of lipids

Lipid nanoparticles (LNPs) have emerged as promising carriers for delivering therapeutic agents, including mRNA-based immunotherapies, in various biomedical applications. The use of LNPs allows for efficient delivery of drugs, resulting in enhanced targeted delivery to specific tissues or cells. These LNPs can be categorized into several types, including liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-polymer hybrid nanoparticles. The preparation of LNPs involves the manipulation of their structural, dimensional, compositional, and physical characteristics via the use of different methods in the industry. Lipids used to construct LNPs can also be derived from various biological sources, such as natural lipids extracted from plants, animals, or microorganisms. This review dives into the different types of LNPs and their preparation methods. More importantly, it discusses all possible biological sources that are known to supply lipids for the creation of LNPs. Natural lipid reservoirs have surfaced as promising sources for generating LNPs. The use of LNPs in drug delivery is expected to increase significantly in the coming years. Herein, we suggest some environmentally friendly and biocompatible sources that can produce lipids for future LNPs production.

Algae-based approaches for Holistic wastewater management: A low-cost paradigm

Aquatic algal communities demonstrated their appeal for diverse industrial applications due to their vast availability, ease of harvest, lower production costs, and ability to biosynthesize valuable molecules. Algal biomass is promising because it can multiply in water and on land. Integrated algal systems have a significant advantage in wastewater treatment due to their ability to use phosphorus and nitrogen, simultaneously accumulating heavy metals and toxic substances. Several species of microalgae have adapted to thrive in these harsh environmental circumstances. The potential of algal communities contributes to achieving the United Nations' sustainable development goals in improving aquaculture, combating climate change, reducing carbon dioxide (CO2) emissions, and providing biomass as a biofuel feedstock. Algal-based biomass processing technology facilitates the development of a circular bio-economy that is both commercially and ecologically viable. An integrated bio-refinery process featuring zero waste discharge could be a sustainable solution. In the current review, we will highlight wastewater management by algal species. In addition, designing and optimizing algal bioreactors for wastewater treatment have also been incorporated.

Combining ABE fermentation and anaerobic digestion to treat with lipid extracted algae for enhanced bioenergy production

As a downstream process output, biobutanol can be produced via acetone, butanol, and ethanol (ABE) fermentation from lipid-extracted algae (LEA), but the leftover residue has not been treated for additional value. In current study, LEA were acid hydrolyzed to extract glucose into the hydrolysate, which was then used for ABE fermentation to produce butanol. In the meantime, anaerobic digestion was performed on the hydrolysis residue to produce methane and release nutrients for algae recultivation. To optimize butanol and methane production, several carbon or nitrogen supplements were applied. The results showed that the hydrolysate produced a high butanol concentration of 8.5 g/L with bean cake supplemented, and the residue co-digested with wastepaper had a higher methane production compared to the direct anaerobic digestion of LEA. The causes of the enhanced performances were discussed. The digestates were reused for algae recultivation and were proved to be effective for algae and oil reproduction. The combined process of ABE fermentation and anaerobic digestion was thus proved a promising technique to treat LEA for economic benefit.

Isolating Fistulifera pelliculosa from the northern Bohai Sea and analyzing biochemical composition, antibacterial and nutrient removal potential

The microalgae located near the estuary of the Liaohe River along the coast of Panjin have long been in an area with large fluctuations in salinity, temperature, and nutrients, and have high-quality alternatives for high-value metabolites. Three strains of microalgae were screened and the biomass of microalgae could be optimized 0.313-0.790 g L^-1 in 10 L bioreactor. The determination results of bioactive substances in these three microalgae showed that, the amount of fucoxanthin in the growth phase II (14 days) was maximum, at 5.354, 6.284 and 14.837 mg g^-1 respectively. The diatoxanthin of Dut-wj-J1 in growth phase III (21 days) could reach 5.158 mg g^-1. Dut-wj-J4 had the highest lipid production efficiency (9.45 mg L^-1 d^-1) followed by Dut-wj-J2 (8.49 mg L^-1 d^-1) and Dut-wj-J1 (8.18 mg L^-1 d^-1) respectively. These bioactive substances have inhibition zones of 7-13 mm against all four strains of bacteria ie., Acetobacter, Rhodococcus erythropolis, Escherichia coli and Bacillus subtilis Cohn respectively. In addition, these microalgae can play a potential role in nutrient enrichment in eutrophic seawater. The NO₃^- degradation rates of these three algae in the first 14 days were 75.0 %, 45.8 % and 100 % respectively, as well as the PO₄^- degradation rates in the first 7 days were 94.8 %, 100 % and 80.9 % respectively. This work manifests the plasticity of algae isolated from the Bohai Sea and provides useful insights for further joint production of bioactive substances.

Hydrothermal Carbonization of Residual Algal Biomass for Production of Hydrochar as a Biobased Metal Adsorbent

Conversion of residual algal biomass to value-added products is essential for enhancing the economics of algae cultivation. Algal hydrochar produced via hydrothermal carbonization of lipid-extracted Picochlorum oculatum is a material rich in oxygen functional groups and carbon (up to 67.3%) and hence a promising candidate for remediation of wastewaters. The hydrothermal carbonization conditions were optimized and the adsorption capacity of the hydrochar was tested for metal removal. By the end of the remediation process, cumulative removal of Al3+, Cu2+, Fe2+, Mg2+, Mn2+, and Pb2+ reached 89, 98, 75, 88, 75, and 100%, respectively. The adsorption of all metals was found to follow pseudo second-order kinetics and the Langmuir isotherm. Overall, when hydrothermal carbonization is applied to lipid-extracted algae, it generates a promising biobased adsorbent with value-added potential in metal remediation.

Algae biorefinery: a promising approach to promote microalgae industry and waste utilization

Microalgae have a number of intriguing characteristics that make them a viable raw material aimed at usage in a variety of applications when refined using a bio-refining process. They offer unique capabilities that allow them to be used in biotechnology-related applications. As a result, this review explores how to increase the extent to which microalgae may be integrated with various additional biorefinery uses in order to improve their maintainability. In this study, the use of microalgae as potential animal feed, manure, medicinal, cosmeceutical, ecological, and other biotechnological uses is examined in its entirety. It also includes information on the boundaries, openings, and improvements of microalgae and the possibilities of increasing the range of microalgae through techno-economic analysis. According to the findings of this review, financing supported research and shifting the focus of microalgal investigations from biofuels production to biorefinery co-products can help guarantee that they remain a viable resource. Furthermore, innovation collaboration is unavoidable if one wishes to avoid the high cost of microalgae biomass handling. This review is expected to be useful in identifying the possible role of microalgae in biorefinery applications in the future.