以菜籽油为唯一碳源,经过富集、驯化、平板分离初筛和复筛,从长期淤积油污的食堂下水道中筛选获得1株脂肪酶产生菌CQNU 3-3。利用16S r DNA序列系统发育分析,结合形态学与生理生化特征确定CQNU 3-3为代尔夫特菌,并将其命名为Delftia tsuruhatensis strain CQNU 3-3。研究发酵条件对菌株产酶的影响发现,该菌株在初始pH为2的酸性条件下,发酵酶活力最高;发酵第1天酶活力即可达到最大,发酵温度为32~37℃较为适宜。对其产生脂肪酶的酶学特性进行分析,表明该酶最适反应pH为7.0,最适反应温度为50℃,Cu~(2+)、尿素、Mg~(2+)和Na+对酶活力有显著的抑制作用,而Zn~(2+)和EDTA可以显著提高酶活力。油脂降解率实验表明该菌株对样品中油脂的降解率可高达73.54%。

Using rapeseed oil as the only carbon source,a thermostable acid lipase strain CQNU 3-3 was isolated from the sewage of the school dining hall through enrichment,domestication,screening and re-screening.The analysis of morphology,physiological and biochemical characteristics,the phylogeny of 16S rDNA sequence indicated that the strain CQNU 3-3 was as a member of Delftia tsuruhatensis and named Delftia tsuruhatensis strain CQNU 3-3.The analysis on the effects of fermentation conditions to the production of enzyme showed that the enzyme activity was the highest at the initial pH 2,the suitable fermentation temperature was 32-37 ℃.The study on enzymatic properties of lipase showed that the optimum reaction pH was 7.0,the reaction temperature was 50 ℃.Zn~(2+) and EDTA could significantly increase the enzyme activity and Cu~(2+),Mg~(2+),Na+and urea could significantly decrease the enzyme activity.Additionally,the degradation rate of the added oil in the sample was high to 73.54%.