LPMOs in cellulase mixtures affect fermentation strategies

The novel enzymes lytic polysaccharide monooxygenases (LPMOs) are capable of oxidatively cleaving polysaccharides, including chitin, cellulose, hemicellulose and starch. Current commercial cellulase preparations contain LPMOs, which increase the rate of cellulose conversion through synergistic action with hydrolytic cellulases. However, these enzymes require oxygen that poses new requirements for processing conditions during saccharification. This is even more true for combined saccharification and fermentation processes. In this study lactic acid production from steam exploded birch was investigated at different temperatures and process setups. In SSF processes the fermenting organisms quickly consumed all the oxygen impeding the activity of the enzyme cocktail. Thus SHF seems to be the preferred setup for lactic acid production when using LPMO containg cellulase cocktails. The amount of oxygen needed to activate LPMOs and the faith of oxidized sugars during fermentation were investigated.

Reference 

Müller et al., 2015, Harnessing the potential of LPMO-containing cellulase cocktails poses new demands on processing conditions. Biotechnology for Biofuels, DOI: 10.1186/s13068-015-0376-y