Abstract
BackgroundMicrobial lipid production using renewable feedstock shows great promise for the biodiesel industry.ResultsIn this study, the ability of a lipid-engineered Yarrowia lipolytica strain JMY4086 to produce lipids using molasses and crude glycerol under different oxygenation conditions and at different inoculum densities was evaluated in fed-batch cultures. The greatest lipid content, 31% of CDW, was obtained using a low-density inoculum, a constant agitation rate of 800 rpm, and an oxygenation rate of 1.5 L/min. When the strain was cultured for 450 h in a chemostat containing a nitrogen-limited medium (dilution rate of 0.01 h−1; 250 g/L crude glycerol), volumetric lipid productivity was 0.43 g/L/h and biomass yield was 60 g CDW/L. The coefficient of lipid yield to glycerol consumption (YL/gly) and the coefficient of lipid yield to biomass yield (YL/X) were equal to 0.1 and 0.4, respectively.ConclusionsThese results indicate that lipids may be produced using renewable feedstock, thus providing a means of decreasing the cost of biodiesel production. Furthermore, using molasses for biomass production and recycling glycerol from the biodiesel industry should allow biolipids to be sustainably produced.
Highlights
Microbial lipid production using renewable feedstock shows great promise for the biodiesel industry
The present study investigated whether low-cost raw materials such as molasses and crude glycerol could serve as substrates for biolipid production and accumulation; the substrate concentration, oxygenation conditions, and inoculum densities were varied
TAG remobilization was avoided because the TGL4 gene, which encodes triglyceride lipase YlTgl4, was deleted from JMY4086 [17]
Summary
Microbial lipid production using renewable feedstock shows great promise for the biodiesel industry. One possible strategy involves the transformation of waste materials and/or co-products, such as whey, crop residues, crude glycerol, or crude fats, into triglycerides or fatty acids using microbial cell factories [3, 4]. These processes are advantageous compared to conventional methods, since they use waste materials generated by various industries as feedstock. Microbial lipid can be produced in close proximity to biodiesel industrial plants and it is easy to scale up their production [5]
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