Fungus, cellulolytic

A wide range of prokaryotic and eukaryotic microorganisms have the potential to produce cellulolytic enzymes when cellulose is present in the growth media (20,23,28,30). However, unlike some of the microorganisms that produce an incomplete cellulase system, T. reesei, a true cellulolytic fungus, produces an array of cellulase enzymes, i.e., the cellulase complex, which is able to hydrolyze cellulose to glucose (23). 

The cellulolytic fungus Trichoderma reesei is well known to produce stable cellulase useful for saccharification of cellulose and is widely used for production of commercial cellulase [1, 2], Fuel ethanol must be produced from cellulosic resources to prevent global warming [3]. The cellulase of this fungus is applicable for producing ethanol from cellulosic materials, but the cost is still a problem [4], Thus, the cellulase productivity of this fungus... 

Sulphopropyl-Sephadex has been used for the purification of (J-D-2-acetamido-2-deoxy-hexosidases A and B from human kidneyand of a (1 - 4)- 3-D-glucan glucanohydrolase from the cellulolytic fungus Trichoderma viride QM 9414. ... 

Nogawa, M., Takahashi, H., Kashiwagi, A., Ohshima, K., Okada, H., and Morikawa, Y. 1998. Purification and characterization of exo-P-D-glucosaminidase from a cellulolytic fungus, Trichoderma reesei PC-3-7. Appl Environ Microbiol 64 890-895. 

As can be seen, the cellulolytic action of the fungus has indeed brought about a two-fold increase in the yield of extractable lignin. The native and enzymatically liberated lignins were then chemically compared and found to be identical in all respects examined (Table 4). 

There are many sources of cellulolytic enzymes however, the fungus Trichoderma viride has proved to be the most effective source to date. The microbiology (25,32) and enzyme kinetics (24,30) studies on this organism have been pioneered by workers such as Reese and Mandels at... 

The proteolysis of cellulases has been previously investigated. Nakayama et al. (14) found that mild proteolysis of endoglucanase from T. reesei by a protease prepared from the same fungus resulted in cellulase enzymes which still possessed cellulolytic activity. Earlier, Eriksson and Petterson (24) investigated the effect of various proteolytic enzymes on the cellulase activities on Penicillium notatum. They found that different proteases affected enzyme activities to different degrees. 

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-... 

Claeyssens, M., van Tilbeurgh, H., Kamerling, J. P., Berg, J., Vrsanska, M., and Biely, P. 1990. Studies of the cellulolytic system of the filamentous fungus Trichoderma reesei QM 9414 substrate specificity and transfer activity of endoglucanase I. Biochem. 1,270,251-256. 

The cellulolytic enzymes of fungi are mostly present in the liquid in which the organism has been grown. The fungus is normally cultured in a liquid medium containing cellulose and different mineral salts. The culturing process is followed by filtration or centrifugation to remove the cells and residual cellulose. 

In addition to Sephadex gels the polyacrylamide gels (Bio-Rad Laboratories, Richmond, California) have been used for separation of cellulolytic enzymes. The cellulases from Sterum sanguinolentum have thus been separated on a polyacrylamide P-150 column by Eriksson and Pettersson (8) and the cellulolytic enzymes from the fungus Chryso-sporium lignorum have been separated on the same type of gel by Eriksson and Rzedowski (11). 

One possible explanation for these different modes of cellulose depolymerization in the same species of wood is that the cellulolytic enzyme molecules of Poria monticola are smaller than those of Polyporus versicolor and for that reason would be able to penetrate and act in regions of the fine structure of the fibers that are not accessible to those of the latter fungus. This hypothesis has led to efforts (as yet incomplete) to determine the molecular size of the cellulolytic enzyme proteins of these two organisms. Another possible explanation is that the initial dissolution of cellulose and other cell-wall polysaccharides is accomplished by catalysts that are not enzyme proteins and therefore could be substantially smaller in molecular size. Halliwell (21) has described experiments on the... 

Badhan AK, Chadha BS, Kaur J, SainiHS, BhatMK. (2007).Production of multiple xylanolytic and cellulolytic enzymes by thermophilic fungus Myceliophthora sp. IMI 387099. Bioresour Technol, 98, 504-510. 

Siinivasan K, Murakami M, Nakashimada Y, Nishio N. (2001). Efficient production of cellulolytic and xylanolytic enzymes by the rumen anaerobic fungus, Neocallimastix frontalis, in a repeated batch culture. J Biosci Bioeng, 91, 153-158. 

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