Monday, May 5, 2008
12-18
Effect of medium carbon source on the hydrolytic potential of cellulases
Dóra Dienes, Kati Réczey, and Zsófia Kádár. Department of Biotechnology and Food Science, Budapest University of Technology and Economics, Szt. Gellért tér 4., Budapest, 1111, Hungary
Lignocellulosic biomass is a potential source of biofuels. Conversion of cellulose from lignocellulosics into sugars performed by enzymatic catalysis requires high enzyme loading to obtain high degree of cellulose conversion that increases the cost of the process. Thus, efficiency of the enzymes has to be improved in order to achieve competitive enzyme technology.
The aim of our experiments was to investigate the connection between the carbon source used in cultivation and the efficiency of the produced enzyme mixture in the hydrolysis of the given substrate. Enzymatic conversion of lignocellulosic materials was carried out using “in-house” fermented enzymes produced by Trichoderma reesei, the well studied soft-rot fungus. Two widely available agricultural residues, wheat straw and corn stover were investigated as carbon sources in the fermentation and as substrates in the hydrolysis. Raw materials were pretreated by steam-explosion in the presence of catalytic amount of sulphur dioxide (at Lund University, Sweden and ENEA,Italy ).
Cultivation of T. reesei RutC30 strain in shake flasks was performed in spent grain-based medium buffered with 0.1 M Tris-maleate (pH 5.6), at 28°C, 200 rpm. The hydrolysis experiments were carried out using 20 FPU per g cellulose cellulase enzyme dosage at 50°C, 2% dry matter content, in 0.05 M acetate buffer solution (pH 4.8). In order to avoid accumulation of cellobiose, b-glucosidase was supplemented to 20 BGL U per g cellulose with commercial enzyme preparation, Novozym 188 (Novozymes). Hydrolytic process was monitored and evaluated by HPLC analysis of the supernatant for various sugars produced.
The aim of our experiments was to investigate the connection between the carbon source used in cultivation and the efficiency of the produced enzyme mixture in the hydrolysis of the given substrate. Enzymatic conversion of lignocellulosic materials was carried out using “in-house” fermented enzymes produced by Trichoderma reesei, the well studied soft-rot fungus. Two widely available agricultural residues, wheat straw and corn stover were investigated as carbon sources in the fermentation and as substrates in the hydrolysis. Raw materials were pretreated by steam-explosion in the presence of catalytic amount of sulphur dioxide (at Lund University, Sweden and ENEA,
Cultivation of T. reesei RutC30 strain in shake flasks was performed in spent grain-based medium buffered with 0.1 M Tris-maleate (pH 5.6), at 28°C, 200 rpm. The hydrolysis experiments were carried out using 20 FPU per g cellulose cellulase enzyme dosage at 50°C, 2% dry matter content, in 0.05 M acetate buffer solution (pH 4.8). In order to avoid accumulation of cellobiose, b-glucosidase was supplemented to 20 BGL U per g cellulose with commercial enzyme preparation, Novozym 188 (Novozymes). Hydrolytic process was monitored and evaluated by HPLC analysis of the supernatant for various sugars produced.
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)