| Summary: | 碩士 === 中臺科技大學 === 食品科技研究所 === 96 === A high mannanase-producing fungal strain was isolated soil sample in central Taiwan. According to morphology and 18S rDNA comparison by microscope and comparison between the partial sequence of 18S rDNA, it was identified to be Asp. niger and was therefore named temporarily as A.niger NCH-318. The enzyme properties of crude mannanase are described as follows: the optimum pH was pH 4.0 and optimum temperature was 60℃. The optimum substrate concentration was 0.9%. The optimal medium composition and cultivation conditions for A. niger NCH-318 are determined using shaking flasks (capacity 250 ml). The results showed that Mandels-Reese medium (M) with 1.5% coconut meal which was defatted by n-hexane, 0.56% yeast extract as nitrogen source, incubation temperature at 40℃, initial pH at 4.0, inoculum size at 106 sproes/ml and shaking rate at 110 rpm. The final enzme activity of 190 U/ml in the culture broth was obtained after 6 days of cultivation.
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