产复合酶优良菌株筛选及苹果渣固态发酵效果研究

通过液态发酵产酶试验和苹果渣固态发酵试验,研究不同丝状真菌产水解酶的活性及产酶优良的霉菌对苹果渣发酵的改质效果,筛选出适用于苹果渣发酵的优良霉菌。结果表明,黑曲霉MHQ1产纤维素酶、果胶酶和木聚糖酶的活性较高,分别为64.7、66.9和216.7U·mL~(-1);米曲霉MMQ1产淀粉酶和蛋白酶的活性较高,分别为1 782.6和83.0U·mL~(-1);烟曲霉MYQ1产蛋白酶和果胶酶的活性较高,分别为128.9和51.6U·mL~(-1)。其中,黑曲霉MHQ1能在果渣基质上良好地生长,对果渣具有较强的降解改质能力,产物中粗蛋白和纯蛋白质量分数分别增至387.5和228.9g·kg~(-1),接菌增率为79.2%和193.8%,且纤维素酶、果胶酶和蛋白酶的活性分别为178.0、150.6和57.5U·g~(-1),纤维素、果胶分别降解28.9%、53.8%,水溶性氨基酸质量分数增至2.7%。采用酵母菌与产复合酶优良的霉菌复合发酵,能显著提高果渣发酵产物中的蛋白质水平,降低抗营养物质的质量分数,提高水解酶和水溶性氨基酸等活性物质的质量分数,有效地发酵果渣为生物蛋白饲料。

Screening of High Yield Multi Enzyme-Producing Strains and Its Effect on Apple Pomace Solid-State Fermentation

Several high enzyme-yield strains were screened through liquid fermentation and apple pomace solid state fermentation experiment by comparing the hydrolytic enzyme activity and product quality of apple pomace fermentation.The results showed that the activity of cellulose (64.7 U·mL^-1), pectinase(66.9 U·mL^-1) and xylanase (216.7 U·mL^-1) produced by Aspergillus niger MHQ1 were comparably high, and the amylase(1 782.6 U·mL^-1) and protease(83.0 U·mL^-1) produced by Aspergillus oryzae MMQ1 were comparably high,and the activity of protease(128.9 U·mL^-1) and pectinase (51.6 U·mL^-1) produced by Aspergillus fumigates MYQ1 were comparably high. Among all,Aspergillus niger MHQ1 grew well on the apple pomace substrate, and fermenting combined with yeast could improve the products quality of apple residue fermentation: the crude protein and pure protein mass fraction of the products increased to 387.5 g·kg^-1and 228.9 g·kg^-1; the efficiency of seed inoculation was enhanced by 79.2% and 193.8% compared with blank samples, and the activities of cellulase, pectinase and protease were 178.0 U·g^-1, 150.6 U·g^-1and 57.5 U·g^-1 ,respectively. Besides the anti-nutrients such as cellulose, pectin were degraded by 28.9% and 53.8%, and water soluble amino acid mass fraction increased to 2.7%. In all, Aspergillus niger MHQ1 fermentation with yeast could significantly improve protein level of fermentation product of apple pomace,reduced the anti-nutrient mass fraction, and increased the hydrolytic enzymes activity and the water soluble amino acids mass fraction.Therefore, Aspergillus niger MHQ1 combined with yeast, could effectively ferment apple pomace to biological protein-rich feed.