Bioprocessing ligno-cellulose into ethanol with recombinant clostridium

A recombinant Gram-positive Clostridia host cell comprising:

• (a) at least one heterologous nucleic acid encoding a plant cell wall degrading enzyme, wherein said host cell is capable of expressing said nucleic acid and of producing and secreting said plant cell wall degrading enzyme;
• and
• (b) at least one nucleic acid encoding an enzyme that converts pyruvate to acetaldehyde optionally combined with at least one heterologous nucleic acid encoding an enzyme that converts acetaldehyde to ethanol wherein said host cell is capable of expressing said nucleic acid;
• and
• (c) a mutation in at least one nucleic acid encoding for an enzyme in a metabolic pathway in said host cell, wherein said pathway produces a metabolite other than acetaldehyde from pyruvate or ethanol from acetaldehyde, and wherein said mutation results in a reduced production of said metabolite, or comprises a nucleic acid encoding for an inhibitor of said enzyme.