Microbial conversion of glycerol: present status and future prospects

Area of Science:

• Biotechnology
• Biochemical Engineering
• Renewable Energy

Background:

• Biodiesel production is increasing globally, but its economic viability is hampered by the low value of its main byproduct, crude glycerol.
• Crude glycerol, contaminated with catalysts and alcohol, is unsuitable for conventional applications.
• Developing markets for glycerol valorization is crucial for the economic sustainability of the biodiesel industry.

Purpose of the Study:

• To provide a comprehensive review of the literature on the bioconversion of glycerol into value-added products.
• To assess various bioconversion pathways, microorganisms, fermentation methods, and product recovery strategies.
• To discuss the economic and engineering challenges associated with the large-scale implementation of glycerol bioconversion processes.

Main Methods:

• Literature review and assessment of 23 different glycerol bioconversion products.
• Analysis of reported microorganisms, fermentation modes, fermentor types, yields, and product purification techniques.
• Discussion of metabolic pathways involved in glycerol bioconversion.

Main Results:

• Bioconversion offers a highly selective alternative to conventional catalytic glycerol transformation, which often requires harsh conditions and yields numerous byproducts.
• Various microorganisms and fermentation strategies can be employed for glycerol bioconversion.
• The review details the potential of numerous glycerol derivatives as value-added products.

Conclusions:

• Bioconversion of crude glycerol presents a promising route for enhancing the economic feasibility of biodiesel production.
• Further research into optimizing bioconversion kinetics, yields, and downstream processing is essential for industrial scale-up.
• Addressing economic and engineering challenges is key to realizing the full potential of glycerol valorization.