Kluyveromyces marxianus has been employed for production ofbiomass, enzymes and ethanol (Belem and Lee, 1998). Recently production of β-xylosidase (EC 3.2.1.37) has been described in K. marxianus and other yeasts (Manzanares et al. 1999) but no detailed information is available on its production by wild or mutant cultures of K. marxianus.It finds application in industry, to hydrolyze bitter compounds from grape fruit during juice extraction and liberation of aroma from grapes during wine making (Manzanares et al. 1999). Cellulase-free xylanases have an important role in reducing consumption of chlorine and chlorine dioxide in paper and pulp industry (Tsujibo et al. 2001) and assist in controlling emanation of toxic compounds in the environment. Yeasts capable of producing glycosidases may be more suitable for the last application as they will require cloning of endo-xylanase gene only (La Grange et al. 2000) for this implication.

For all above applications, the organism and its enzymes are required to be thermotolerant or thermostable (Chen et al. 2000). Moreover, enzyme is also secreted in large quantities following growth of the organism on cheap media to suite the end use. Among its inducers, namely, xylose, cellobiose, sucrose, and lactose (Furlan et al. 2000), the last one in cheese whey or sucrose in molasses may be economically more viable inducers for mass production of this enzyme. To achieve, all these objectives, a de-oxy-D-glucose- (Rajoka et al. 1997) + cycloheximide-resistant mutant (Gerlinger et al. 1997), which hyper-produced β-xylosidase was used. Further studies will be done to develop a continuous system for enzyme production which would fulfill process requirement. Kinetic and thermodynamic studies (Rashid and Siddiqui, 1998) provided sufficient insight into the thermostability of the enzyme (Vieilli and Zeikus, 1996) which was attributed to accompanying chaperone activity. Endo-β-xylanase and β-xylosidase act in synergism to breakdown xylan-lignin complex in paper and pulp industry (Tsujibo et al. 2001) K. marxianus produces β-xylosidase with out any accompanying cellulases (Belem and Lee, 1998) This organism produces β-galactosidase, β-glucosidase, and pectinase as well (Belem and Lee, 1998) and may be suitable for biobleaching of pulps if xylanase gene could be incorporated in K. marxianus (La Grange et al. 2001).

BELEM, M.A.F. and LEE, B.H. Production of bioingredients from Kluyveromycess marxianus grown on whey: an alternative. Critical Reviews in Food Science and Nutition. October1998, vol. 38, no.1, p. 565-598.

CHEN, J.; LU, Z.; SAKON, J. and STITES, W.E. Increasing the thermostability of staphylococcal nuclease: implications for the origin of protein thermostability. Journal of Molecular Biology, January 2000, vol. 303, no. 1, p. 125-130.

FURLAN, A.S.; SCHNEIDER, A.S.L.; MERCKLE, R.; CARVALHO-JOHANS, M.F. and JONAS, R. Formulation of lactose-free, low-cost culture medium for the production of β-galactosidase by Kluyveromyces marxianus. Biotechnology Letters, July 2000, vol. 22, no. 7, p. 589-593.

GERLINGER, U.M.; GUCKEL, R.; HOFFMANN, M.; WOLF, D.H. and HILT, W. Yeast cycloheximide-resistant crl mutants are proteasome mutants defective in protein degradation. Molecular Biology of the Cell, December 1997, vol. 8:, no. 12, p. 2487-2499.

LA GRANGE, D.C.; PRETORIUSM I.S.; CLAEYSSENS, M. and VAN ZYL, W.H. Degradation of xylan to D-xylose by recombinant Saccharomyces cerevisiae co expressing the Aspergillus niger beta-xylosidase (xlnD) and the Trichnoderma reesei xylanase ii (xyn2) genes. Applied and Environmental Microbiology, 2001, vol. 67, no. 12, p. 5512-5519.

MANZANARES, P.; RAMON, D. and QUEROL, A. Screening of non-Saccharomyces wine yeasts for production of β-xylossidase activity. International Journal of Food Microbiology, February 1999, vol. 46, no.2, p. 105-112.

RAJOKA, M.I.; BASHIR, A. and MALIK, K.A. Mutagenesis of Cellulomonas biazotea for enhanced production of xylanases. Bioresource Technology, January 1997, vol. 62, no.1, p. 99-108.

RASHID, M.H. and SIDDIQUI, K.S. Thermodynamic and kinetic study of stability of the native and chemically modified β-glucosidase from Aspergillus niger. Process Biochemistry, January1998, vol. 33, no. 2, p. 109-115.

TSUJIBO, H.; TAKADA, A.; KOSAKA, M.; MIYAMOTO, K. and INAMORI, Y. Cloning, sequencing, and expression of the gene encoding an intracellular β-D-xylosidase from Streptomyces thermoviolaceus OPC-520. Bioscience Biotechnology and Biochemistry, August 2001, vol. 65, no. 8, p. 1824-1831.

VIEILLI, C. and ZEIKUS, J.G. Thermozymes: identifying molecular determinants of protein structural and functional stability. Trends in Biotechnology, January 1996, vol. 14, no. 1, p. 183 190.

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