Symbiotic Associations: Key Factors That Determine Physiology and Lipid Accumulation in Oleaginous Microorganisms

Symbiosis naturally provides an opportunity for microorganisms to live together by mutual or one-way benefit. In symbiotic relationships, the microorganisms usually overcome the limitations of being free-living. Understanding the symbiotic relationships of oleaginous microorganisms provides potential route for the sustainable production of microbial-based alternative fuels. So far, several studies have been conducted in oleaginous microorganisms for the production of alternative fuels. However, some oleaginous microorganisms require high quantity of nutrients for their growth, and high level of energy and chemicals for harvest and separation of lipid bodies. Symbiotic associations can successfully be applied to address these issues. Of symbiotic associations, lichens and selective species of oleaginous endosymbiotic mucoromycotina have received substantial interest as better models to study the evolutionary relationships as well as single-cell oil production. Construction of artificial lichen system composed of cyanobacteria and oleaginous yeast has been achieved for sustainable production of lipids with minimum energy demand. Recently, endosymbiotic mucoromycotina species have been recognized as potential sources for biofuels. Studies found that endohyphal bacterium influences lipid profiling in endosymbiotic mucoromycotina species. Studies on the genetic factors related to oleaginous characteristics of endosymbiotic mucoromycotina species are scarce. In this regard, this review summarizes the different forms of symbiotic associations of oleaginous microorganisms and how symbiotic relationships are impacting the lipid formation in microorganisms. Further, the review also highlights the importance of evolutionary relationships and benefits of co-culturing (artificial symbiosis) approaches for sustainable production of biofuels.

A Review on Oleaginous Microorganisms for Biological Wastewater Treatment: Current and Future Prospect

The water scarcity issue is becoming a critical issue to the climate change, industrialization and urbanization. Prompt to the advances in biotechnology, Oleaginous microorganisms have been discovered and successfully applied in biological wastewater treatments, which are highly effective for wastewater clean-up and energy efficient lipid conversion to value-added products. This paper aims to review the recent advances of the application of different types of Oleaginous microorganisms (e.g. yeasts, microalgae, and fungi) as well as the advantages, limitations and application fields (food industry, municipal waste and chemical plant). The future prospect and challenges of Oleaginous microorganism that warrant in environmental settings or engineered systems are also highlighted in the review. In order to improve the Technology Readiness Level (TRL), the future research direction should be more focussed on the economic and environmental studies.

Lignocellulosic Biomass as a Substrate for Oleaginous Microorganisms: A Review

Microorganisms capable of accumulating lipids in high percentages, known as oleaginous microorganisms, have been widely studied as an alternative for producing oleochemicals and biofuels. Microbial lipid, so-called Single Cell Oil (SCO), production depends on several growth parameters, including the nature of the carbon substrate, which must be efficiently taken up and converted into storage lipid. On the other hand, substrates considered for large scale applications must be abundant and of low acquisition cost. Among others, lignocellulosic biomass is a promising renewable substrate containing high percentages of assimilable sugars (hexoses and pentoses). However, it is also highly recalcitrant, and therefore it requires specific pretreatments in order to release its assimilable components. The main drawback of lignocellulose pretreatment is the generation of several by-products that can inhibit the microbial metabolism. In this review, we discuss the main aspects related to the cultivation of oleaginous microorganisms using lignocellulosic biomass as substrate, hoping to contribute to the development of a sustainable process for SCO production in the near future.

Lignocellulosic Biomass as a Substrate for Oleaginous Microorganisms: A Review

The microorganisms able of accumulating lipids in high percentages, known as oleaginous microorganisms, have been widely studied as an alternative for producing oleochemicals and biofuels. Microbial lipid, so called Single Cell Oil (SCO), production depends on several growth parameters, including the nature of the carbon substrate, which must be efficiently taken up and converted into storage lipid. Οn the other hand, substrates considered for large scale applications must be abundant and of low acquisition cost. Among others, lignocellulosic biomass is a promising renewable substrate containing high percentages of assimilable sugars (hexoses and pentoses). However, it is also highly recalcitrant and therefore it requires specific pretreatments in order to release its assimilable components. The main drawback of lignocellulose pretreatment is the generation of several by-products that can inhibit the microbial metabolism. In this review, we discuss the main aspects related to the cultivation of oleaginous microorganisms using lignocellulosic biomass as substrate, hoping to contribute to the development of a sustainable process for SCO production in the near future.