In order to utilize the agricultural waste products for animal feeds, two high xylanase-producing mold strains were selected from various sources of samples.
The optimum conditions of xylanase production and the characteristics of the mold enzyme were investigated, and summarized as follows.
1. Two Aspergillus niger strains (experimental No. 1701 and 430) showed the high xylanase activity.
2. The highest xylanase production was obtained at pH 5.0-6.0 in two days.
3. Xylanase production in strain 1701 was increase with the addition of carboxy methyl cellulose, NH₄H₂PO₄ and corn steep liquor as carbon sources and natural nutrients, as respectively, while the other carbon, nitrogen, phosphate sources, natural nutrients and minerals gave no remarkable effect.
In the strain 430, the enzyme procuction was not effected with the above substrate sources.
4. Maximum xylan hydrolysis reaction with the crude enzyme extract (33.3 v/v) was obtained in the 2% substrate concentration at pH 5.0 and 60℃ in three hours in both strains.
5. Maximum xylan hydrolysis rate was 95% at the optimum conditions for xylanase activity.
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