低分子质量黄原胶具有抗氧化、抑菌等特殊生物活性,在食品、农业等领域都有所应用,具有较高的市场价值。黄原胶内切酶的高效表达是酶法水解生产低分子质量黄原胶的关键因素。该研究首次在毕赤酵母GS115中表达来自Microbacterium sp.XT11的黄原胶内切酶,随后对其发酵条件进行了优化,并对重组黄原胶内切酶的酶学性质进行了分析。结果表明,以GAP为启动子的重组毕赤酵母的最佳发酵条件为30 ℃、pH 6.0、220 r/min、接种量5%,在7-L发酵罐中重组黄原胶内切酶酶活力达到1 230 U/L。重组黄原胶内切酶在pH 5.5~7.5、20~45 ℃ 下比较稳定,最适作用条件为pH 6.0、40 ℃。重组黄原胶内切酶可直接作用于黄原胶主链得到分子质量为1 400 Da 左右的低分子质量黄原胶,为低分子质量黄原胶的工业化生产提供了一个可行的途径。
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