Ethanol Production via Fungal Consolidated Bioprocessing

Production of biofuels from lignocellulosic biomass has a number of associated difficulties. A pretreatment step is usually required to enhance saccharification yield. Researchers have been investigating biological alternatives such as the consolidated bioprocessing (CBP), which converts lignocellulose into the desired products in one step.

University of Nottingham researchers, led by Stuart Wilkinson, have recently tested the production of bioethanol from brewers spent grains (BSG) using fungal consolidated bioprocessing (CBP). A fungal CBP system includes a filamentous fungal species, which secretes the enzymes that deconstruct biomass, and a yeast species, which ferments liberated sugars into ethanol.

After evaluating several pairings of fungi, the pair of Aspergillus oryzae and Saccharomyces cerevisiae NCYC479 was found to yield the highest concentrations of ethanol. Further analysis of the selected carbohydrate degrading (CAZy) genes expressed by A. oryzae in the system showed that hemicellulose was deconstructed first, followed by cellulose.

While the CBP approach yields lower ethanol, it requires less energy and water inputs, and will be subject to further investigation and optimization.