Enzyme production by filamentous fungus for lignocellulose hydrolysis

Author(s)

Beatriz Merchel Piovesan Pereira

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2012-04-12

Examining board members

Aline Carvalho da Costa; Roberto Ruller; Francisco Maugeri Filho

• Advisor: Jose Geraldo da Cruz Pradella; Aline Carvalho da Costa

Abstract

The production of lignocellulolytic enzymes by Trichoderma reesei RUT-C30 was optimized in shake flasks and 0.5 and 3L bioreactors to maximize the enzymatic titles and volumetric productivity. The carbon sources considered were sugar cane bagasse (1% w/v) pretreated by the hydrothermal process (BH) or steam explosion, with (BED) and without (BEX) delignification. The medium contained proteose peptone, Tween 80 and saline solution. Commercial cellulose Celufloc200 (CE) was used for comparison. Increased production of cellulolytic enzymes in flasks was obtained with BED as carbon source (1.38 ± 0.11 FPU / ml) when compared to CE (0.78 ± 0.14 FPU / ml), and this material was selected as carbon source for further studies. The production of hemicellulases (xylanases) was similar for the two carbon sources (U / mL): 18.03 ± 1.56 with BED and 20.04 ± 1.50 with CE. Variation of the concentration of the salt solution, carbon source and nutrients led to an increased production of cellulolytic enzymes: 1.89 ± 0.12 (medium with doubled saline solution concentration) and 2.73 ± 0.09 (medium with 2% w/v BED and nutrients proportional to the carbon source) in shake flasks. Supplementation of the carbon source with soybean meal, sucrose, pretreatment liquor, lactose and glycerol was studied and soybean meal has been selected as supplement. The preparation of a mixture medium containing doubled saline solution, soybean meal and nutrients proportional to the concentration of the carbon source allowed increasing the production of enzymes for (in FPU / ml): 3.33 ± 0.10 (MIX15 - containing 1.5% w/v BED) , 3.78 ± 0.33 (MIX20) and 3.67 ± 0.34 (MIX30) in shake flasks. Xylanase activities were higher than 130 U/mL. In a 3L bioreactor, production of cellulolytic enzymes using MIX15 medium reached 2.29 ± 0.20 FPU / mL. For the standard medium (BED 1% w/v) the peak activity was 1.14 ± 0.32 FPU / mL. Increasing the concentration of the carbon source in the bioreactor to 3% w/v starting from MIX15 resulted in a cellulolytic activity of 4.20 ± 0.34 FPU / mL. Xylanase activity reached values higher than 180 U/mL in the bioreactor. The performance of the enzyme cocktail produced in MIX15 medium was evaluated for the hydrolysis of BED and BH, and compared to the cocktail produced in the standard medium and to a cocktail commercially available (Sigma). The values of conversion of cellulose to glucose were higher for the cocktail MIX15 compared to the other cocktails when using 3 or 5% solids, with or without adding commercial beta-glucosidase (Novozym 188) (AU)

• FAPESP's process: 10/12811-5 - Enzyme production by Penicillium echinulatum for lignocellulose hydrolysis
• Grantee: Beatriz Merchel Piovesan Pereira
• Support Opportunities: Scholarships in Brazil - Master