RESUMEN
Cellobiohydrolase II of Trichoderma reesei was produced in laboratory and pilot scale using a transformant strain of Saccharomyces cerevisiae harbouring a multicopy expression plasmid. Different strategies were compared for concentration and partial purification of the enzyme produced in a 200 1 pilot cultivation. After efficient separation of biomass and sub-cellular particulate matter, a combination of ultrafiltration and adsorbent treatment for removal of protein impurities was used to provide a concentrate for chromatographic purification. Effective purification of the CBH II protein was obtained by passing the concentrate through a column of DEAE Sepharose, on which almost all the yeast proteins were adsorbed. The purified enzyme reacted with antibodies prepared against T. reesei CBH II and catalyzed partial solubilization of crystalline cellulose to soluble sugars.
Asunto(s)
Glicósido Hidrolasas/biosíntesis , Hongos Mitospóricos/enzimología , Trichoderma/enzimología , Biotecnología , Celulosa 1,4-beta-Celobiosidasa , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/aislamiento & purificación , Proyectos Piloto , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genéticaRESUMEN
The focus in the development of pulping processes has usually been exclusively on cellulose. However, hemicellulose could serve as a valuable source of hexose and pentose sugars. Consequently, it should not be destroyed in a process designed for very high cellulose fibre yields. Novel procedures developed for production of ethanol by the fermentation of pentoses as well as hexoses provide new possibilities of hemicellulose utilization. Many fungi produce extracellular hemicellulases. In the present work the production of xylanase and beta-xylosidase with strains of Aspergillus and Trichoderma was studied. The enzymes were used for the hydrolysis of xylan. Xylose was fermented to ethanol by the mold Fusarium oxysporum.