白酒大曲产酯化酶犁头霉的分离鉴定及产酶条件优化

Isolation and identification of high-yield esterase Absidiain Daqu and Optimizationof enzyme production conditions

以安徽金种子集团中温大曲为原料,从中筛选能够产酯化酶的发酵菌种并鉴定其种类,再以酯化力为目标值研究该菌株产酯化酶的发酵培养基组成和发酵条件。结果表明,从金种子中温大曲中分离得到1株高产酯化酶的菌株LD06,通过形态学观察、分子鉴定及Biolog鉴定确定该菌株为犁头霉。以该菌株发酵产物中的酯化力为目标值,得到该犁头霉的固体发酵培养基组成为:麸皮10g,玉米粉1.5g、酵母粉2.0g、亚麻籽油1g/100g·培养基、硫酸铵0.2g、蒸馏水10mL;培养条件分别为温度36℃、时间45h。该条件下得到的犁头霉产酯化酶的酯化力为9.32g/L,与该菌株初始酯化力相比提高了22.55%。

The aim of this study was to screen high-yield strains of esterase from Daqu in order to increase the content of esters in Daqu.Medium-temperature Daqu was used as material to screen high-yield esterase producing strains and identify the types of strain.Then we studied on enzyme production conditions of the strains with the target value of esterifying power.The result showed that high-yield esterase producing strain-LD06 was isolated from medium-temperature Daqu,and the morphological and molecular identification results confirmed that the strain was Absidia.Esterifying power was used as reference index to confirm the culture media,which was summed up as follows:10 g wheat bran as culture substrate,corn flour as the optimum carbon source with the contents of 1.5 g,yeast as the optimum nitrogen source with the contents of 2.0 g,flaxseed oil as inducer with the contents of 1 g/100 g;other composition and addition in the medium with 0.2 g(NH4)2 SO4 and 10 mL H2 O.With the increase of fermentation time and temperature,esterifying power showed significant increase firstly and then decreased.Culture conditions which concluded temperature and time was confirmed at 36℃and 45 h,respectively.Under these fermentation medium and conditions the highest esterifying power was 9.32 g/L,which was increased by22.55%than the control.