TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Process: The esterase comprises one or more enzymes chosen from esterase and feruloyl esterase. The esterase comprises amino acid sequence exhibiting at least 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% identity to mature polypeptide of SEQ ID NOs: 133-137, or its fragments with feruloyl esterase activity. The enzyme comprises amino acid sequence of SEQ ID NOs: 133-137 or its mature polypeptide. The feruloyl esterase is one or more chosen from formaldehyde activating enzyme (FAE)1, FAE-A, FAE-C, and FAE-D. The process (P1) involves recovering the refined pretreated cellulosic material. The process (P1) further involves separating liquor from the pretreated cellulosic material, and contacting the liquor with feruloyl esterase and recycling the liquor to contact the liquor with pretreated cellulosic material or refined pretreated cellulosic material. The process (P1) further involves recycling the liquor to a new pretreatment of pretreated cellulosic material with esterase composition. The process (P1) further involves post-treating the refined pretreated cellulosic material with enzymatic pre-treatment, chemical pre-treatment, mechanical pre-treatment and/or a physical pretreatment process. The process (P1) involves contacting esterase (0.0005-5, 0.001-5, 0.0025-5 mg, 0.005-5 mg, 0.005-4.5, 0.005-4, 0.005-3.5, 0.005-3, 0.005-2, 0.005-1, 0.075-1, or 0.1-1 mg) with pretreated cellulosic material (1 g). The contacting process is performed with a total solids (TS) of 1-50%, 2-40%, 2-35%, 3-30%, 3-25%, 4-20%, or 5-10%. The contacting process is performed at a pH of 2-9, 3-7.5, 3.5-7, 4-6.5, 4.5-6.5, 4.5-6.0, 5, 6, or 5-5.5. The contacting process is performed at a temperature of 20-70 degrees C, 25-65 degrees C, 30-65 degrees C, 35-65 degrees C, 40-60 degrees C, 45-55 degrees C, or 45-50 degrees C. The contacting process is performed for 5 minutes-35 hours, 10 minutes-15 hours, 10-15 hours, 10-20 hours, 20-24 hours, 24-30 hours, or 1-72 hours. The process (P2) further involves recovering saccharified pretreated cellulosic material from saccharification. The process (P4) further involves recovering fermentation product from the fermentation process. Sequences not defined here may be found at ftp://ftp.wipo.int/pub/published_pct_sequences/publication. EXAMPLE - No suitable example given.