Influence of high temperature and ethanol on thermostable lignocellulolytic enzymes

• Published in: Journal of industrial microbiology & biotechnology 2013-05, Vol.40 (5), p.447-456
• Main Authors: Skovgaard, Pernille Anastasia, Jørgensen, Henning
• Format: Article
• Language: English
• Subjects: Biochemistry; Bioenergy/Biofuels/Biochemicals; Biofuel production; Biofuels; Bioinformatics; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cellulase; Cellulases - metabolism; Cellulose 1,4-beta-Cellobiosidase; Costs; Distillation; Energy; Energy consumption; Enzymatic activity; enzyme activity; Enzyme Assays; Enzyme kinetics; Enzyme Stability - drug effects; Enzymes; Ethanol; Ethanol - pharmacology; ethanol production; Fermentation; Fundamental and applied biological sciences. Psychology; Genetic Engineering; High temperature; Hot Temperature; Hydrolysis; hydrophobic bonding; Inactivation; Industrial applications and implications. Economical aspects; Inorganic Chemistry; Life Sciences; Lignin; Lignin - metabolism; Lignocellulose; Microbiology; polyacrylamide gel electrophoresis; Production costs; Proteins; Recycling; Studies; temperature; thermal stability; Vacuum distillation
• ISSN: 1367-5435; 1476-5535
• DOI: 10.1007/s10295-013-1248-8

Lignocellulolytic enzymes are among the most costly part in production of bioethanol. Therefore, recycling of enzymes is interesting as a concept for reduction of process costs. However, stability of the enzymes during the process is critical. In this work, focus has been on investigating the influence of temperature and ethanol on enzyme activity and stability in the distillation step, where most enzymes are inactivated due to high temperatures. Two enzyme mixtures, a mesophilic and a thermostable mixture, were exposed to typical process conditions [temperatures from 55 to 65 °C and up to 5 % ethanol (w/v)] followed by specific enzyme activity analyses and SDS-PAGE. The thermostable and mesophilic mixture remained active at up to 65 and 55 °C, respectively. When the enzyme mixtures reached their maximum temperature limit, ethanol had a remarkable influence on enzyme activity, e.g., the more ethanol, the faster the inactivation. The reason could be the hydrophobic interaction of ethanol on the tertiary structure of the enzyme protein. The thermostable mixture was more tolerant to temperature and ethanol and could therefore be a potential candidate for recycling after distillation.