Microalgae Metabolic Modelling: Formulation, Analyses, Applications, and Challenges

Microalgae have recently become the focus of many studies due to their broad biotechnological applications. They have been considered as the sustainable energy resources for the third-generation biofuels as well as cell-factories of valuable bio-based products. Photoautotrophic microalgae use CO۲ as C-source and light as energy (E)-source for their growth. This can mitigate atmospheric CO۲, the cause of global climate change, and yield neutral lipids or carbohydrates (Park, Nguyen, and Jin ۲۰۱۹). Additionally, microalgae have complex metabolism and can produce many valuable compounds such as proteins, pigments, medicines and cosmetics with commercial demand. On the other hand, organic compounds can be consumed by heterotrophic/mixotrophic microalgae to produce cell mass rich in carbohydrate/lipid. This is advantageous since wastewaters rich in organic compounds can support microalgal growth and their product formation (Patel et al. ۲۰۱۹).To make the microalgal based-processes commercial, many studies have been carried out to make the processes cost effective (Benavente-Valdés et al. ۲۰۱۶). Efforts have been devoted to optimizing the culture medium and operating conditions as well as discovering the superior strains. On the other hand, metabolic models have been generated by reconstruction of biochemical reaction networks alongside metabolic balance analysis (FBA) using linear programming to predict the cellular behavior. This allows strain engineering by thorough investigation of cell activities and finding the optimal gene manipulations as well as flux redirection towards the desired cell characteristics. Using these models along with critical analyses may enhance microalgal productivities and this in turn can reduce the costs and support commercialization of their products (Tibocha-Bonilla et al. ۲۰۱۸b).

Keywords:

Microalgae , Photoautotroph , Heterotroph , Mixotroph , Metabolic Model , Flux Balance Analysis (FBA) , Light Cycle