Team doubles efficiency of converting seaweed into biofuel

A team of scientists from UC Berkeley and the University of Illinois, Urbana-Champaign reached a scientific breakthrough in their research — they doubled the efficiency of converting seaweed into biofuel.

The researchers, who published the study in the August issue of Applied and Environmental Microbiology, focused on converting marine biomass, particularly red seaweed, into biofuel by introducing a new strain of yeast that reduces the amount of time required to produce ethanol by 30 percent. The research was funded by the BP-backed Energy Biosciences Institute.

Hydrolyzing seaweed yields the sugars glucose and galactose, which are individually fermented to produce ethanol. However, the original yeast strain that ultimately ferments the sugars into ethanol does so one sugar at a time, first utilizing all the glucose before using the galactose, said Yong-Su Jin, one of the lead researchers and an assistant professor of microbial genomics at University of Illinois, Urbana-Champaign.

Because the original yeast strain ferments only one sugar at a time, the process is inefficient, according to Jonathan Galazka, a UC Berkeley graduate student in the Department of Molecular and Cell Biology and co-author of the study.

“The issue is that it takes too long,” he said. “In the biofield industry, it’s not the best way to do it.”

Jin said a key component of the study, which produced the new strain of yeast, was the identification of  two genes — the cellobiose transporter, which moves the sugars into the yeast cell, and intracellular beta-glucosidase, which breaks down the sugars — from a new fungus. They allow the assimilation of cellobiose into the new strain of yeast’s cell to be simultaneous with the fermentation of galactose, greatly shortening the time necessary to ferment the sugars into a viable biofuel.

“We need to produce ethanol from marine biomass, and the ultimate goal is to produce it economically,” said Jin “We are doing the fermentation as the last step, which is the most important step that determines the economics.”

According to Jin, there is a good possibility that seaweed and other marine biomass will become a viable source of fuel since east Asian countries, such as Japan and Korea, are surrounded by the sea and do not have sufficient land to cultivate fuel on the ground.

“In terms of CO2 and global climate change, we need to reduce fuel … in the air, and according to the preliminary research, the CO2 (consumption) rate by marine biomass is much higher,” Jin said. “It’s a solution for reducing global CO2.”