United States: A University of Illinois (U of I) metabolic engineer has developed a strain of yeast that could turn red seaweed into a viable future biofuel. The findings will be published in Biotechnology and Bioengineering.
"When Americans think about biofuel crops, they think of corn, miscanthus and switchgrass. ln small island or peninsular nations, though, the natural, obvious choice is marine biomass," told Yong-Su Jin, a U of I assistant professor of microbial genomics and a faculty member in its Institute for Genomic Biology.
So far, producers of biofuels made from terrestrial biomass crops have found it tricky to break down unruly fibres and extract fermentable sugars. As well, the pre-treatment processes employed to release the sugars resulted in toxic by-products and thus inhibited succeeding microbial fermentation, he detailed.
In contrast, he noted, marine biomass can be degraded simply into fermentable sugars, and its production rates and distribution range are greater than terrestrial biomass.
"However, making biofuels from red seaweed has been problematic because the process yields both glucose and galactose, and until now galactose fermentation has been very inefficient," he noted.
Jin and his colleagues, though, only just detected three genes in Saccharomyces cerevisiae, the microbe applied most frequently to ferment the sugars, whose overexpression bolstered galactose fermentation by 250 percent against a control strain.
"This discovery greatly improves the economic viability of marine biofuels," Jin declared.
The overexpression of one specific gene – a truncated form of the TUP1 gene – caused galactose fermentation numbers to skyrocket. The new strain used up both glucose and galactose nearly thrice as fast as the control strain: in eight hours instead of 24, he specified.
"When we targeted this protein, the metabolic enzymes in galactose became very active. We can see that this gene is part of a regulating or controlling system," he said.
Jin told that galactose is one of the most plentiful sugars in marine biomass, meaning that its enhanced fermentation will be of industrial use for producers of seaweed biofuel.
And he elaborated that marine biomass is an eye-catching renewable source for biofuel production due to three reasons:
The production yields of marine plant biomass are much greater per unit area than those of terrestrial biomass
Marine biomass can be de-polymerised more easily than other biomass crops because it lacks recalcitrant lignin and cellulose crystalline structures
The rate of carbon dioxide fixation by marine biomass is much higher than by terrestrial biomass, such that it is an attractive choice for sequestrating and recycling carbon dioxide
Natalia Real (Fishing Information and Services)