Marine Yeast Converts Red Seaweed Sap into Ethanol

In India, researchers from the Central Salt and Marine Chemicals Research Institute (CSMCRI) have demonstrated for the first time the production of bioethanol from red seaweed biomass with the help of a marine yeast strain, as reported in the March 2013 issue of Bioenergy Research journal.

The potential of macroalgae, commonly known as seaweeds, as feedstock for bioethanol production has been recognized, but the fermentation process mediated by conventional yeast strains is hindered by high salt concentration in the seaweed sap. One needs to remove the salt from the sap by means of a sophisticated and expensive desalting process prior to fermentation if terrestrial yeast is used. The CMSRI researchers attempted to overcome this fermentation problem by employing a salt tolerant marine yeast strain isolated from the West coast of India. The ability and efficiency of the marine yeast strain was evaluated in a preliminary fermentation test using galactose sugar at varied salt concentrations. Subsequently the yeast was used to ferment saline sugar-rich sap or hydrolysate extracted from biomass of the red seaweed Kappaphycus alvarezii which is rich in carageenan polysaccharide composed of galactose sugar. The utility of the said yeast strain, later identified as Candida sp, for fermentation under saline condition was confirmed as it yielded ethanol ranging from 1.23 to 1.76 percent at varying sugar and salt contents.

According to the researchers, this is the first organized study for the utilization of marine yeast for converting red algal biomass into ethanol under highly saline condition.