TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Host cell: In method (P1 to P3), the host cell comprises endogenous nucleic acid encoding a fatty acyl-coA dehydrogenase. The host cell is modified such that expression of the fatty acyl-coA dehydrogenase is attenuated relative to the level of expression in a non-modified cell. The host cell is a bacterial cell, a fungal cell, a plant, animal, or human cell. The bacterial cell is an Escherichia coli cell. The fungal cell is a yeast cell. The host cell (C2 and C3) further comprises a recombinant nucleic acid encoding a naturally secreted protein, where the secreted protein is fused to the biomass polymer-degrading enzymes. The naturally secreted protein is OsmY from E. coli. The biomass polymer-degrading enzymes are a xylanase and a protein comprising an endoxylanase catalytic domain. The xylanase is xsa from Bacteroides ovatus. The protein comprises an endoxylanase catalytic domain is xyn10B from Clostridium stercorarium. The fatty alcohol-forming fatty acyl-coA reductase is mfar1 from Mus musculus. In method (P3), the host cell comprises endogenous nucleic acid encoding at least one alcohol dehydrogenases, where the host cell is modified such that expression of the alcohol dehydrogenase is attenuated relative to the level of expression in a non-modified cell. The host cell (C4) further comprises an endogenous nucleic acid encoding a fatty acyl-coA dehydrogenase, at least one alcohol dehydrogenases or a naturally secreted protein, where the host cell is modified such that expression of the alcohol dehydrogenases is attenuated relative to the level of expression in a non-modified cell, and the secreted protein is fused to the biomass polymer-degrading enzymes. The fatty acyl-coA reductase is acr1 from Acinetobacter baylyi. Preferred Components: The thioesterase is ltesA from E. coli. The fatty acyl-coA synthetase is fadD from E. coli. The alcohol dehydrogenase is adhB from Zymomonas mobilis. The pyruvate decarboxylase is pdc from Zymomonas mobilis. The acyl-transferase is the wax ester synthase atfA from Acinetobacter strain ADP1. The biomass polymer-degrading enzymes are a xylanase and a protein comprising an endoxylanase catalytic domain. The xylanase is xsa from Bacteroides ovatus. The endoxylanase catalytic domain is from xyn10B from Clostridium stercorarium. The biomass polymer-degrading enzymes are a protein containing a cellobiohydrolase catalytic domain, a beta-glucosidase, and a protein containing cellulase catalytic domain. The cellobiohydrolase catalytic domain is from ce16A from Cellvibrio japonicus, the beta-glucosidase is ce13B from Cellvibrio japonicus, and the cellulase catalytic domain is from eel from Bacillus sp. D04.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The culturing medium does not comprise free fatty acids or alcohol.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The biomass polymer is hemicellulose or cellulose, where the hemicellulose is xylan. EXAMPLE - No suitable example given.