MICROBIAL PENTOSANASES: III. SOME FACTORS AFFECTING THE PRODUCTION OF PENTOSANASES BY ASPERGILLUS NIGER AND TRICHODERMA VIRIDE

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Abstract
Of a number of carbohydrates tested, holocellulose from wheat straw and L-arabinose were the better substrates for production of pentosanase by Trichoderma viride. D-Xylose did not induce synthesis of the enzyme by the fungus. Production in a synthetic medium was increased by the addition of malt sprouts, distillers' dried solubles, or glutamic acid.Under the same conditions the production of pentosanase by Aspergillus niger was favored by the water-soluble pentosan of wheat flour, holocellulose, and wheat bran. Both D-xylose and L-arabinose induced synthesis of enzyme. In the synthetic medium the addition of yeast extract, corn steep liquor, malt sprouts, or a number of other nitrogenous adjuncts increased the yield of pentosanase. A medium containing 3% bran ground to pass a 20-mesh sieve, 3% corn steep liquor neutralized with ammonium hydroxide, and 1% calcium carbonate was developed for the production of pentosanase by A. niger. Maximum yield was obtained in 60 hours. The pentosanase had an optimum pH of 5.0 and was stable for 30 minutes at 30 °C between pH 4.0 and 5.8. The pentosanase could be precipitated from the culture filtrates with 76% ethanol and when stored as a dry powder at 2 °C was stable for at least 1 year.