摘要
本研究旨在选育高产纤维素降解菌,以提高纤维素降解效率.试验从肉牛瘤胃液中通过刚果红染色法筛选出纤维素降解菌,然后经常压室温等离子体(ARTP)诱变后筛选出高效纤维素降解菌株,并对其秸秆降解效果进行研究.结果表明:1)从肉牛瘤胃液中筛选得到初始菌株纤维素降解菌C8,其全酶(FPA)、外切葡聚糖酶(C1)、内切葡聚糖酶(CMC)和β-葡萄糖苷酶(β-Gase)活力分别为3.96、1.08、2.21和0.51 U/mL,其秸秆干物质降解率为35.79％,经生物学鉴定为枯草芽孢杆菌(Bacillus subtilis),命名为枯草芽孢杆菌C8.2)以枯草芽孢杆菌C8为初始菌株通过ARTP进行诱变,筛选得到突变菌株AC83,其FPA、C1、CMC和β-Gase活力分别为 6.31、1.18、3.63 和 1.05 U/mL,相较初始菌株分别提高了 59.34％、9.26％、64.25％和105.88％;秸秆干物质降解率为43.64％,较初始菌株提高了 21.93％.3)突变菌株AC83经过连续6代培养,具有良好的遗传稳定性.本研究筛选得到突变菌株AC83具有较强的纤维素降解能力,为提高饲料转化率提供了更多可能.
Abstract
The aim of this study was to breed high-yield cellulose degrading bacteria to improve the efficiency of cellulose degradation.Cellulose degrading bacteria were screened from rumen fluid of beef cattle by Congo-Red staining method,and then high cellulose degrading bacteria were screened after(atmospheric room tem-perature plasma)ARTP mutagenesis,and the degradation effects of straw were studied.The results show as follows:1)the initial cellulose-degrading strain C8 was screened from rumen fluid of beef cattle.The holoen-zyme(FPA),exoglucanase(C1),endoglucanase(CMC)and β-glucosidase(β-Gase)activities of strain C8 were 3.96,1.08,2.21 and 0.51 U/mL,respectively,and the dry matter degradation rate of straw was 35.79％.It was biologically identified as Bacillus subtilis and named Bacillus subtilis C8.2)Using Bacillus subtilis C8 as the initial strain,the mutant strain AC83 was selected by ARTP mutagenesis,and its FPA,C,,CMC and β-Gase activities were 6.31,1.18,3.63 and 1.05 U/mL,respectively.Compared with the original strain,they increased by 59.34％,9.26％,64.25％and 105.88％,respectively.The dry matter degradation rate of straw was 43.64％,which was 21.93％higher than that of the initial strain.3)The mutant strain AC83 had good genetic stability after 6 successive generations of culture.In this study,the mutant strain AC83 is screened to have strong cellulose degradation ability,which provides more possibilities for improving feed con-version rate.[Chinese Journal of Animal Nutrition,2024,36(12):8126-8136]
维普
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