Fig. 1From: Engineered Thermoanaerobacterium aotearoense with nfnAB knockout for improved hydrogen production from lignocellulose hydrolysatesMetabolic pathway in Thermoanaerobacterium aotearoense SCUT27. Key enzymes and genes in the pathway: lactate dehydrogenase (ldh, accession no. V518_0188); pyruvate formate lyase (pfl, accession no. V518_2608); pyruvate:ferredoxin oxidoreductase (pfor, accession no. V518_2353); [NiFe]-hydrogenase (ech, accession no. V518_1955-1960); [FeFe]-hydrogenase (hfs, accession no. V518_1526); bifurcating [FeFe]-hydrogenase, (hyd, accession no. V518_0972-0976); NADH-dependent reduced ferredoxin:NADP+ oxidoreductase, (nfnAB, accession no. V518_0931-0932); phosphate acetyltransferase (pta, accession no. V518_1312); acetate kinase, (ack, accession no. V518_1311); bifunctional acetaldehyde-CoA/alcohol dehydrogenase, (adhE, accession no. V518_0444); alcohol dehydrogenase, (adhA, accession no. V518_0933); alcohol dehydrogenase, (adhB, accession no. V518_1046). Although PFL has been found in T. aotearoense SCUT27, no formate was detected during the fermentation of T. aotearoense SCUT27 and SCUT27/∆nfnABBack to article page