Rhodococcus sp.SHZ-1腈水合酶的高酶活发酵工艺

Fermentation Production of High Activity Nitrile Hydratase by Rhodococcus sp.SHZ-1

通过研究发酵过程中溶氧、生物量、腈水合酶活力以及残糖的变化规律和搅拌速度、通气量、接种量及诱导剂对产腈水合酶的影响,确立了5L发酵罐中Rhodococcus sp.SHZ-1腈水合酶的高酶活发酵工艺参数。结果表明,发酵过程中溶氧控制在30%以上有利于菌体快速生长和腈水合酶的合成。在pH7.2,温度30℃的发酵条件下,适宜的腈水合酶合成工艺条件为:接种量10%,通气量1.0vvm,搅拌速度采用由初始的200r/min调至500r/min的变速调控方式,同时于48h补加产酶诱导剂,发酵液腈水合酶的最高酶活力达到了9500U/mL,是摇瓶培养时最高酶活力8208U/mL的1.2倍,且比未进行工艺优化时最大产酶期缩短了20～24h,其最佳产酶期为52～60h。

The various rules for dissolved oxygen, biomass, nitrile hydratase （NHase） activity, Glu concentration and the effect of agitation speed, inoculation, aeration and elicitor aerylonitrile on nitrile hydratase （NHase） activity were studied. The fermentation parameters for production of high activity NHase by Rhodococcus sp. SHZ-1 on 5 L batch fermentor were established. The results indicated that over 30 % dissolved oxygen was good for the accumulation of biomass and production of NHase in the fermentation. The optimum inoculation and aeration were decided as 10 % and 1.0 vvm, respectively, and the agitation speed was set at 200 rpm and raised to 500 rpm according to the growth of strain and the production of NHase under pH 7.2 and the temperature 30 ~C. At the same time, the highest NHase activity in the Rhodoeoeeus sp. SHZ-1 cells was obtained by adding the 0.3 % elicitor after 48 h cultivation; the NHase activity was in- creased to 9 500 U/mL which was 1.2 times than that in flake; the maximum time for production of NHase was between 52 h and 60 h,and the periods of fermentation was diminished from 20 h to 24 h.