Production of cellulases

A literature survey indicated that very little work has been done to produce an optimal cellulase system as described above. Here, we used solid-state fermentation (SSF) to achieve this objective. SSF processes, such as the "koji" process, have been used extensively for amylase production on wheat bran in Japan its application was extended to cellulase production on wheat bran and Ugnocellulosic materials by Toyama (13), Since then, wheat bran has become an important substrate for producing various products by SSF (14-20), In this study, we tested various lignocellulosic substrates for the production of cellulase and )3-glucosidase from T, reesei QMY-1 by SSF. 

Langsford et al. reported that Cellulomonas fimi culture supernatants contained cellulase and proteinase activities, for which there appeared to be a relationship. Glucose repressed the synthesis of both activities and cellulose induced both 60), Adding cellulose to Cellulomonas sp. (NRCC 2406) cultures stimulated growth and improved production of cellulases 61). Optimum conditions for growth and cellulase production were pH 6.5 and 30 C. The addition of glucose in the presence of cellulose inhibited growth. Several species of Cellulomonas have cellobiose phosphorylase. 

A pilot study for large scale production of cellulase from Triohoderma reesei has been developed at the U.S. Army Natick Development Center (Fig. 7 (20)). In March 1977, enzyme produc-... 

The preparation of xylanases from cloned systems has permitted production of cellulase-free xylanases. The xylanases produced from cloned... 

Potato pulp and potato pulp residue (after acidic treatment) and nutrient salt solution and potato protein liquor, respectively, were used for the production of cellulases and hemicellulases by Trichoderma reesei Rut C30 in a continuously operated bioreactor, (Klingspohn and Schiigerl... 

Targonski, Z. and Pielecki, J., Continuous semi-solid cultivation for the production of cellulase by Trichoderma reesei mutants using a polyurethane foam carrier and a liquid medium, Acta-Biotechnol. 1995 vol. 15, no. 3, pp. 289-296. 

Tuerker. M. and Mavituna, E, Production of cellulase by freely suspended and immobilized cells of Trichoderma reesei, Enzyme-Microb.-Technol. 1987. vol. 9, no. 

Targonski and Pielecki investigated the production of cellulase using immobilized mycelium of Trichoderma reesei mutants on polyurethane foam impregnated... 

In the reported structures of products of cellulase digestion of xyloglucans from different sources, there has been considerable variation that may reflect different action-patterns of enzyme preparations as much as actual differences in the structures of the polysaccharides. On reaction of xyloglucan from the walls and culture medium of suspension-cultured, sycamore cells,26,27 four major oligosaccharide products were isolated. Stuctures were proposed for the heptamer (Z) and the nonamer (3). 

Because of its ability to produce and secrete the complete set of cellulolytic enzymes, thus making it particularly potent in hydrolyzing the cellulose polymer to glucose monomers, the soft-rot fungus Trichoderma, in particular T. reesei has been the focus of cellulase research for decades (8). The preferred substrates used by most researchers for cellulase production are pure celluloses such as Avicel, Solka-floc, and cotton (9). Cellulase production by Trichoderma is controlled by a complex metabolic regulation (10-12). Cellulose acts (indirectly) as an inducer for the production of cellulases. Expression of cellulases is furthermore subject to repres-... 

Figure 3 shows the progression of cellulase production (lU L h" ) over the years 1972 to 1989. A 200-fold increase in the productivity of cellulase enzyme... 

The crystallinic structure and lignin existence in cellulosic materials prevent attack by microorganisms. The growth of fungi is too slow in untreated raw materials for commercial production of cellulase. In order to design an economically viable technical process, these difficulties must be overcome by a suitable mechanical or chemical pretreatment. 

Pretreatment technology for cellulosic materials for commercial production of cellulase by solid-state fermentation for various raw materials with low cost ... 

M. Mandels We are very interested in your results. In our experiments with Trichoderma viride we have had low yields of cellulase in 0.5-1.0% cellobiose culture, similar to your results with P. fluorescens. However, we could get excellent production of cellulase in these cultures when cellobiose consumption was slowed by sub-optimal temperatures, reduced aeration, or certain imbalances in the nutrients. We believe that high cellobiose levels repress cellulase formation. When the metabolic rate was decreased, however, the repression was relieved and cellobiose acted as an inducer. We believe, in fact, that cellobiose, the product of cellulase action, is the true inducer in a cellulose culture. Here the cellobiose is consumed by the fungus as rapidly as it is produced and never builds up to repressing levels. 

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