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Cyanobacteria hold significant potential as industrial biotechnology (IB) platforms for the production of a wide variety of bio-products ranging from biofuels such as hydrogen, alcohols and isoprenoids, to high-value bioactive and recombinant proteins. Underpinning this technology, are the recent advances in cyanobacterial “omics” research, the development of improved genetic engineering tools for key species, and the emerging field of cyanobacterial synthetic biology. These approaches enabled the development of elaborate metabolic engineering programs aimed at creating designer strains tailored for different IB applications. In this review, we provide an overview of the current status of the fields of cyanobacterial omics and genetic engineering with specific focus on the current molecular tools and technologies that have been developed in the past five years. The paper concludes by giving insights on future commercial applications of cyanobacteria and highlights the challenges that need to be addressed in order to make cyanobacterial industrial biotechnology more feasible in the near future.

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AbstractDue to increasing concerns about global warming and dwindling oil supplies, the world’s attention is turning to green processes that use sustainable and environmentally friendly feedstock to produce renewable energy such as biofuels. Among them, biodiesel, which is made from nontoxic, biodegradable, renewable sources such as refined and used vegetable oils and animal fats, is a renewable substitute fuel for petroleum diesel fuel. Biodiesel is produced by transesterification in which oil or fat is reacted with short chain alcohol in the presence of a catalyst. The process of transesterification is affected by the mode of reaction, molar ratio of alcohol to oil, type of alcohol, nature and amount of catalysts, reaction time, and temperature. Various studies have been carried out using different oils as the raw material; different alcohols (methanol, ethanol, butanol); different catalysts; notably homogeneous catalysts such as sodium hydroxide, potassium hydroxide, sulfuric acid, and supercritical fluids; or, in some cases, enzymes such as lipases. This article focuses on the application of heterogeneous catalysts for biodiesel production because of their environmental and economic advantages. This review contains a detailed discussion on the advantages and feasibility of catalysts for biodiesel production, which are both environmentally and economically viable as compared to conventional homogeneous catalysts. The classification of catalysts into different categories based on a catalyst’s activity, feasibility, and lifetime is also briefly discussed. Furthermore, recommendations have been made for the most suitable catalyst (bifunctional catalyst) for low-cost oils to valuable biodiesel and the challenges faced by the biodiesel industry with some possible solutions.

Summary A lot of research has been performed on Cyanobacteria and microalgae with the aim to produce numerous biotechnological products. However, native strains have a few shortcomings, like limitations in cultivation, harvesting and product extraction, which prevents reaching optimal production value at lowest costs. Such limitations require the intervention of genetic engineering to produce strains with superior properties. Promising advancements in the cultivation of Cyanobacteria and microalgae have been achieved by improving photosynthetic efficiency through increasing RuBisCO activity and truncation of light‐harvesting antennae. Genetic engineering has also contributed to final product extraction by inducing autolysis and product secretory systems, to enable direct product recovery without going through costly extraction steps. In this review, we summarize the different enzymes and pathways that have been targeted thus far for improving cultivation aspects, harvesting and product extraction in Cyanobacteria and microalgae. With synthetic biology advancements, genetically engineered strains can be generated to resolve demanding process issues and achieve economic practicality. This comprehensive overview of gene modifications will be useful to researchers in the field to employ on their strains to increase their yields and improve the economic feasibility of the production process.

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