By Paul Grad |
A research team from Pohang University of Science and Technology (Pohang, South Korea; www.postech.ac.kr), led by professor Gyoo Yeol Jung, and Seoul National University (Seoul, South Korea; www.useoul.edu), led by professor Sang Woo Seo, has developed a new microorganism — dubbed Vibrio sp. dhg — that can be a promising platform for producing biofuels with brown macroalgae.
Extensive studies have been conducted to utilize non-edible biomass as a feedstock for producing fuels and other useful bioproducts and brown macroalgae has been seen as an alternative feedstock. Brown macroalgae grow up to three times faster than the starch crops and only require light and seawater to grow.
The most prominent sugars in brown macroalgae are alginate and mannitol. The utilization of brown macroalgae by conventional microbial platforms has been limited due to the inability to metabolize one of the principal sugars, alginate (a copolymer of α–L-guluronate and β–D-mannuronate). While conventional microbial platforms such as Escherichia coli can easily metabolize mannitol, its ability to assimilate alginate is hindered by the fact that it lacks certain related genes. Although E. coli can be engineered to utilize alginate, its growth rate and metabolic activity are still too low for industrial application.
The team established a genetic toolbox for the engineering of Vibrio sp.dhg. It also demonstrated the new microorganism’s ability to rapidly produce ethanol (a biofuel); 2,3-butanediol (a raw material for plastics); and lycopene (a physiologically active substance) from brown macroalgae/sugar mixture with high productivity and yield.
The new microorganism is expected to enhance the efficiency of the microbial fermentation process using not only algae, but also conventional glucose-based biomass.