Inhibitors of R. oryzae in corn cob and corn stover hydrolysates were identified.

For sugar degradation products, furfural and HMF were more toxic than weak acids.

For phenolics from lignin, syringaldehyde and trans-cinnamic acid were most toxic.

They strongly inhibited lactate dehydrogenase, but not alcohol dehydrogenase.

They thus shifted the metabolic flux from lactic acid to ethanol biosynthesis.