Characterization and RNA-seq transcriptomic analysis of a Scenedesmus obliqnus mutant with enhanced photosynthesis efficiency and lipid productivity

Advances in Algomics technology: Application in wastewater treatment and biofuel production

Advanced sustainable bioremediation is gaining importance with rising global pollution. This review examines microalgae's potential for sustainable bioremediation and process enhancement using multi-omics approaches. Recently, microalgae-bacterial consortia have emerged for synergistic nutrient removal, allowing complex metabolite exchanges. Advanced bioremediation requires effective consortium design or pure culture based on the treatment stage and specific roles. The strain potential must be screened using modern omics approaches aligning wastewater composition. The review highlights crucial research gaps in microalgal bioremediation. It discusses multi-omics advantages for understanding microalgal fitness concerning wastewater composition and facilitating the design of microalgal consortia based on bioremediation skills. Metagenomics enables strain identification, thereby monitoring microbial dynamics during the treatment process. Transcriptomics and metabolomics encourage the algal cell response toward nutrients and pollutants in wastewater. Multi-omics role is also summarized for product enhancement to make algal treatment sustainable and fit for sustainable development goals and growing circular bioeconomy scenario.

New insights into raceway cultivation of Euglena gracilis under long-term semi-continuous nitrogen starvation

This study aimed to investigate the physiological responses of Euglena gracilis (E. gracilis) when subjected to semicontinuous N-starvation (N-) for an extended period in open ponds. The results indicated that the growth rates of E. gracilis under the N- condition (11 ± 3.3 g m^-2 d^-1) were higher by 23% compared to the N-sufficient (N+, 8.9 ± 2.8 g m^-2 d^-1) condition. Furthermore, the paramylon content of E.gracilis was above 40% (w/w) of dry biomass in N- condition compared to N+ (7%) condition. Interestingly, E. gracilis exhibited similar cell numbers regardless of nitrogen concentrations after a certain time point. Additionally, it demonstrated relatively smaller cell size over time, and unaffected photosynthetic apparatus under N- condition. These findings suggest that there is a tradeoff between cell growth and photosynthesis in E. gracilis, as it adapts to semi-continuous N- conditions without a decrease in its growth rate and paramylon productivity. Notably, to the author's knowledge, this is the only study reporting high biomass and product accumulation by a wild-type E. gracilis strain under N- conditions. This newly identified long-term adaptation ability of E. gracilis may offer a promising direction for the algal industry to achieve high productivity without relying on genetically modified organisms.

The Prospects of Algae-Derived Vitamins and Their Precursors for Sustainable Cosmeceuticals

Aquatic algae are a rich source of a wide range of bioproducts intended to compete for a sizable global market share. Thanks to the gradual shift towards the use of natural products, microalgae-derived bioactive compounds offer an ecofriendly and vegan option to the cosmeceutical sector, whose products aim to improve skin health but currently consist of mostly synthetic chemicals. In particular, algae-derived vitamins and their precursors are being explored and widely used in the cosmeceuticals industry as compounds that contain biologically active ingredients with therapeutic benefits. The present review highlights the current strategies for industrial production of an array of vitamins from algae for cosmeceutical applications. When compared to traditional plant sources, algae have been found to accumulate vitamins, such as A, B1, B2, B6, B12, C and E, in high concentrations. The purpose of this review is to provide context for the development of a green and sustainable algae-derived bioeconomy by summarizing and comparing the current market for vitamins and precursors derived from algae, as well as presenting novel strategies and key findings from the most recent research in this area. Emphasis is placed on novel biotechnological interventions that encompass genetic modifications, genetic engineering, and media development to enhance vitamin biosynthesis.

Microalgae-based biotechnological sequestration of carbon dioxide for net zero emissions

Excessive carbon dioxide (CO₂) emissions into the atmosphere have become a dire threat to the human race and environmental sustainability. The ultimate goal of net zero emissions requires combined efforts on CO₂ sequestration (natural sinks, biomass fixation, engineered approaches) and reduction in CO₂ emissions while delivering economic growth (CO₂ valorization for a circular carbon bioeconomy, CCE). We discuss microalgae-based CO₂ biosequestration, including flue gas cultivation, biotechnological approaches for enhanced CO₂ biosequestration, technological innovations for microalgal cultivation, and CO₂ valorization/biofuel productions. We highlight challenges to current practices and future perspectives with the goal of contributing to environmental sustainability, net zero emissions, and the CCE.

Recent Progress on Systems and Synthetic Biology of Diatoms for Improving Algal Productivity

Microalgae have drawn much attention for their potential applications as a sustainable source for developing bioactive compounds, functional foods, feeds, and biofuels. Diatoms, as one major group of microalgae with high yields and strong adaptability to the environment, have shown advantages in developing photosynthetic cell factories to produce value-added compounds, including heterologous bioactive products. However, the commercialization of diatoms has encountered several obstacles that limit the potential mass production, such as the limitation of algal productivity and low photosynthetic efficiency. In recent years, systems and synthetic biology have dramatically improved the efficiency of diatom cell factories. In this review, we discussed first the genome sequencing and genome-scale metabolic models (GEMs) of diatoms. Then, approaches to optimizing photosynthetic efficiency are introduced with a focus on the enhancement of biomass productivity in diatoms. We also reviewed genome engineering technologies, including CRISPR (clustered regularly interspaced short palindromic repeats) gene-editing to produce bioactive compounds in diatoms. Finally, we summarized the recent progress on the diatom cell factory for producing heterologous compounds through genome engineering to introduce foreign genes into host diatoms. This review also pinpointed the bottlenecks in algal engineering development and provided critical insights into the future direction of algal production.

Emerging Trends in Genetic Engineering of Microalgae for Commercial Applications

Recently, microalgal biotechnology has received increasing interests in producing valuable, sustainable and environmentally friendly bioproducts. The development of economically viable production processes entails resolving certain limitations of microalgal biotechnology, and fast evolving genetic engineering technologies have emerged as new tools to overcome these limitations. This review provides a synopsis of recent progress, current trends and emerging approaches of genetic engineering of microalgae for commercial applications, including production of pharmaceutical protein, lipid, carotenoids and biohydrogen, etc. Photochemistry improvement in microalgae and CO2 sequestration by microalgae via genetic engineering were also discussed since these subjects are closely entangled with commercial production of the above mentioned products. Although genetic engineering of microalgae is proved to be very effective in boosting performance of production in laboratory conditions, only limited success was achieved to be applicable to industry so far. With genetic engineering technologies advancing rapidly and intensive investigations going on, more bioproducts are expected to be produced by genetically modified microalgae and even much more to be prospected.