利用柑橘皮固体发酵生产复合酶菌株的选育

UTILIZATION OF ORANGE PEELS: SCREENING OF MULTIENZYME-PRODUCING FUNGAL STRAIN IN SOLID-STATE FERMENTATION

本试验对14个菌株以柑橘皮为主要原料固体发酵生产复合酶的生产性能进行了比较, 发现宇佐美曲霉Aspergillus usaanii具有较好的复合酶产率,为进一步提高该菌株的产酶能力, 我们利用γ-射线辐射对其进行了诱变育种,选育得到一株纤维素酶活提高26%、酸性蛋白酶提高28%、木聚糖酶提高24.5%的突变菌株AU—C33。采用正交试验方法对该菌株的基础培养基进行了优化,结果表明豆粕和尿素含量对各酶活具有极显著影响。以柑橘粉计,当添加23% 豆粕、8%麸皮、3%尿素,水分含量在60%,28℃培养60h后,CMCase、FPA、β-葡萄糖苷酶、酸性蛋白酶和木聚糖酶分别达到了20.8U/g、7.25U/g、74.7U/g、7248.4U/g和3222.6U/g。

Orange peels were studied in terms of their abilities to support microbe growth and extracellular enzyme production of different strains. Of all the fungi tested, Aspergillus usaanii proved to be the most potent strain and produced highly active multienzyme system in solid-state fermentation. To improve the productivity of Aspergillus usaanii ,60Co γ radiation was used in the work and a mutant Aspergillus usaanii -C33 was obtained. Acid protease, CMCase and xylanase of the mutant were improved by 28%, 26% and 24.5% respectively. Soymeal and urea were found to have significant effects on the multienzyme production. The optimizing content of soymeal and urea were 15.5% and 3% of orange peels powders respectively. Under initial moisture content of 60% and after culturing 60h under 28℃, yields as high as 20.8U/g, 7.25U/g, 74.7U/g, 7248.4U/ g and 3222.6 U/g of dry weight of CMCase, FPA, β -glucosidase, acid protease and xylanase , respectively ,were obtained by orthogonal test.