Scale-up and economic analysis of the production of ligninolytic enzymes from a side-stream of the organosolv process

BACKGROUNDOrganosolv pretreatment produces a hemicellulose-rich stream with limited applications due to its toxicity. In this study, beech wood organosolv liquor was valorized through the production of ligninolytic enzymes, the extraction of ganoderic acid and the detoxification of this process stream. RESULTSLaccase and manganese peroxidase (MnP) were produced in 30L bioreactors by the white-rot fungi Ganoderma lucidum and Irpex lacteus, respectively, using the hemicellulose-rich liquor as carbon source. Both fungi caused a significant reduction in the hemicellulose stream toxicity (between 6.1 and 8.3 times lower). The extraction of ganoderic acid (24.3mgg(-1) of G.lucidum biomass) as a fungal metabolite with high pharmacological activity greatly increased the profitability of the process. Finally, the economic viability of the proposed valorization strategy was analyzed on the basis of the operational costs estimated for the process scale-up. The specific costs of MnP and laccase production were Euro2.27kU(-1)and Euro1.08kU(-1), respectively, which are 1109 and 78 times lower than the average price of commercially available enzymes. CONCLUSIONIt was found that the integration of the proposed valorization strategy into an organosolv-based biorefinery would help to increase the economic feasibility of this pretreatment technology. (c) 2018 Society of Chemical Industry