Studies on the chromatographic fractionation of Trichoderma reesei cellulases by hydrophobic interaction

Lignocellulosic agriculture wastes as biomass feedstocks for second-generation bioethanol production: concepts and recent developments

Production of liquid biofuels, such as bioethanol, has been advocated as a sustainable option to tackle the problems associated with rising crude oil prices, global warming and diminishing petroleum reserves. Second-generation bioethanol is produced from lignocellulosic feedstock by its saccharification, followed by microbial fermentation and product recovery. Agricultural residues generated as wastes during or after processing of agricultural crops are one of such renewable and lignocellulose-rich biomass resources available in huge amounts for bioethanol production. These agricultural residues are converted to bioethanol in several steps which are described here. This review enlightens various steps involved in production of the second-generation bioethanol. Mechanisms and recent advances in pretreatment, cellulases production and second-generation ethanol production processes are described here.

Liquid chromatographic and electrophoretic characterisation of extracellular beta-glucosidase of Pleurotus ostreatus grown in organic waste

The production of beta-glucosidase by the ligninolytic fungus Pleurotus ostreatus has been studied in different culture media containing agro-industrial wastes. The enzyme is purified by anion-exchange chromatography, the molecular mass and isoelectric point of purified beta-glucosidase are measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing and the stability and kinetic parameters of the enzyme assessed by spectrophotometry. It has been established that the retention time, molecular mass and isoelectric point of the enzyme depend on the composition of the culture media while the activity and stability of beta-glucosidases of different origin were very similar. The combined chromatographic and electrophoretic methods have proved to be suitable techniques for the purification and characterisation of the beta-glucosidases produced by the ligninolytic fungus Pleurotus ostreatus in different culture media.

Comparative study on the fractionation of cellulases on some hydrophobic interaction chromatography adsorbents

In this work, a comparative study for the fractionation of Trichoderma reesei cellulases on five different hydrophobic interaction chromatography adsorbents (Butyl-Sepharose 4 FF, Phenyl-Sepharose 6 FF, Octyl-Sepharose 4 FF, Epoxy-Sepharose CL-6B and Polypropylene glycol-Sepharose CL-6B) is shown. The influence of the mobile phase composition on the chromatographic behaviour of T. reesei cellulases complex was evaluated using different concentrations of ammonium sulphate in the eluent buffer. A selective separation of beta-glucosidase with two-fold increase in specific activity and good recoveries of cellobiase activity were obtained with Butyl-Sepharose 4 FF and Phenyl-Sepharose 6 FF using 7% (w/v) ammonium sulphate in the eluent buffer. A beta-glucosidase fractionation was also obtained with Epoxy-Sepharose CL-6B, using 13% (w/v) of the salt in the mobile phase.

Hydrophobic interaction chromatography of proteins

In this article, an overview of hydrophobic interaction chromatography (HIC) of proteins is given. After a brief description of protein hydrophobicity and hydrophobic interactions, we present the different proposed theories for the retention mechanism of proteins in HIC. Additionally, the main parameters to consider for the optimization of fractionation processes by HIC and the stationary phases available were described. Selected examples of protein fractionation by HIC are also presented.