NOVELTY - Method of increasing biomass degradation, comprises (A) providing a mutant or transgenic plant having reduced O-acetylation of one or more plant cell wall polysaccharides in the mutant or transgenic plant compared to the O-acetylation of one or more plant cell wall polysaccharides of a corresponding non-mutant or non-transgenic plant, (B) obtaining biomass from the mutant or transgenic plant, and (C) subjecting the biomass to a degradation procedure, and yielding degraded biomass.    USE - The method is useful for increasing biomass degradation.    ADVANTAGE - The method provides increasing biomass degradation with improved yield.    DETAILED DESCRIPTION - Method of increasing biomass degradation, comprises (A) providing a mutant or transgenic plant having reduced O-acetylation of one or more plant cell wall polysaccharides in the mutant or transgenic plant compared to the O-acetylation of one or more plant cell wall polysaccharides of a corresponding non-mutant or non-transgenic plant, where the mutant or transgenic plant comprises a gene encoding a polypeptide having a polypeptide sequence comprising SEQ ID NOs. 113, 114, 115, 116, 117, 118, 119, 120, 121, and 124, where the mutant or transgenic plant has reduced expression of the gene or reduced activity of a protein encoded by the gene compared to the expression of the gene or activity of the protein encoded by the gene in the corresponding non mutant or non-transgenic plant, (B) obtaining biomass from the mutant or transgenic plant, and (C) subjecting the biomass to a degradation procedure, and yielding degraded biomass, where the reduced O-acetylation of one or more plant cell wall polysaccharides in the mutant or transgenic plant increases the amount of degraded biomass compared to the amount of degraded biomass generated from the degradation of biomass obtained from the corresponding non-mutant or non-transgenic plant. INDEPENDENT CLAIMS are included for: (1) a method of increasing the yield of fermentation product from a fermentation reaction, comprising step (A)-(C) as above pre se, (D) incubating the degraded biomass with a fermentative organism under conditions suitable to yield a fermentation product, where an increased yield of fermentation product from the fermentation reaction is obtained, as compared to the yield of fermentation product obtained from a fermentation reaction using degraded biomass from the corresponding non-mutant or non-transgenic plant; (2) a non Arabidopsis mutant plant, comprising a mutation in a gene encoding a polypeptide comprising the polypeptide sequence, where the non-Arabidopsis plant has reduced O-acetylation activity as compared to a corresponding non-Arabidopsis plant lacking the mutation; (3) a seed of the mutant plant; (4) a plant comprising an RNAi-inducing vector, where the vector generates RNAi against a gene encoding the polypeptide comprising the polypeptide sequence; and (5) a trans genie plant, comprising a construct containing an acetyl esterase gene having the polynucleotide sequence of SEQ ID NO. 107, SEQ ID NO. 111, an ortholog of SEQ ID NO. 107 or an ortholog of SEQ ID NO. 111, where the transgenic plant has reduced O-acetylation of one or more polysaccharides as compared to a corresponding plant lacking the construct, where sequences not defined here may be found at ftp://ftp.wipo.int/pub/published-pct-sequences/publication