Biotechnology 81 biofuel 65 Article 64 Biomass 59 cellulose 59 Fermentation 54 biomass 53 Enzymes 51 metabolism 50 Yeast 47 Lignin 46 enzyme activity 46 Genes 45 Cellulose 43 nonhuman 43 biotechnology 42 Metabolism 40 Saccharification 40 fermentation 40 gene expression 40 hydrolysis 40 lignin 39 Glucose 38 Biochemistry 37 Ethanol 37 controlled study 36 enzyme 36 yeast 33 RNA 32 Enzymatic hydrolysis 30