曲霉固液态发酵产壳聚糖降解酶组分及酶学特性分析

Comparative Study of Chitosan Degradation Enzymes from Aspergillus sp. in Solid-State and Liquid-State Fermentation

以壳聚糖酶产生菌——曲霉为出发菌株进行固液态发酵,旨在比较其产物酶组分和酶学性质。结果表明固态发酵产酶组分复杂,除具有壳聚糖降解活性外,还具有多种常见水解酶酶活如蛋白酶、纤维素酶和果胶酶等;液态发酵所得酶组分较简单,不仅具有较大壳聚糖降解活性,还表现出少量蛋白酶和纤维素酶活性。固液态发酵产物酶学性质不同,最适反应温度分别为45℃和40℃,适宜温度分别为40-55℃和35-40℃,分别在40-50℃和30℃稳定性较高;最适反应p H分别为5.8和5.2,分别在p H4.6-6.4和p H4.6-5.8范围内具有较高活性,在p H4.6和p H5.2时稳定性最高。由此说明,固液态发酵产酶组分和相关酶学性质不同,在工业应用中有不同的作用表现。

Aspergillus sp. was cultured in solid and liquid fermentation condition respectively, enzyme production from which was studied. The results showed that solid-state fermentation produced more enzyme components than liquid state fermentation did. Enzyme preparation from solid state fermentation showed many kinds of hydrolytic enzyme activity like that of protease, cellulase, pectinase, amylase, lipase and hemcellulase beside to chitosan degradation activity, and enzyme preparation from liquid fermentation showed weak protease and cellulase activity beside to chitosan degradation activity. The optimal temperature for chitosan degradation of these two enzyme preparation was 45℃ and 40℃, and they showed high chitosan degradation activity at 40-55℃ and 35-40℃, respectively. Furthermore, the optimal p H of them was p H5.8 and p H5.2, and they showed high chitosan degradation activity at p H4.6-6.4 and p H4.6-5.8, respectively. These results indicated that Aspergillus sp. could produce different enzymes with different characteristics in solid and liquid state fermentation conditions. Thus solid state fermentation can be used to produce enzymes with chitosan degradation activities.