利用稻谷壳水解液在气升式生物反应器中发酵生产单细胞蛋白

Production of Single-Cell Protein from Hydrolysate of Rice Hull in External loop Airlift Bioreactors

以稻谷壳水解液为原料 ,采用树状假丝酵母 AS1 .2 57( Candida arborea AS1 .2 57) ,在罐体高径比为 2 .9和上升管与下降管的直径之比为 6.6的外循环气升式生物反应器中发酵生产单细胞蛋白 .研究了通风量、装料量、空气喷嘴直径等工艺和结构参数对发酵的影响 ,得到了较佳的发酵操作参数 .在发酵前 2 4 h的通风量为 1 .1 m3/( m3· min) ,后 2 4 h的通风量为 1 .4m3/( m3· min)～ 1 .5m3/( m3· min) ,起始装料量为 8.5L～ 9.0 L,起始 p H为 4.5～ 5.0 ,发酵温度为 2 9± 1℃的操作条件下 ,经 48h的发酵 ,可得到较佳的结果 .在无筛板 ,带一块筛板和带二块筛板的外循环气升式生物反应器中 ,发酵 48h后的干基粗蛋白含量分别为 61 .3%、62 .9%、64.5% ,发酵液中干物质重分别为 2 0 .8mg/ml、2 1 .2 mg/ml、2 1 .3mg/ml,总糖利用率分别为 78.2 %、83.9%、81 .4% ,均高于机械搅拌生物反应器 ,气升式生物反应器内加装筛板可提高发酵得率 .

The experiments of production of single cell protein were carried out from hydrolysate of rice hull by Candida arborea AS1 257 in the external loop airlift bioreactors with a height to diameter ratio of 2 9 and a ratio of rise diameter to downcomer diameter of 6 6 The effects of gas flow rate,liquid volume and gas sparger hole diameter on single cell protein production were investigated.After a total culture of 48h,the best results were obtained under air flow rate of 1 1 m 3/(m 3·min) during culture time of 0～24h,air flow rate of 1 4～1 5m 3/(m 3·min) during culture time of 24～48h and initial liquid volume of 8 5～9 0L at culture temperature of 29±1℃ and initial pH of 4 5～5 0 A comparison of single cell protein production was made between the external loop airlift bioreactors and the mechanically stirred tank bioreactor.After a total culture time of 48 hours under optimized operation conditions,61 3% dry substrate protein content,20 8mg/ml biomass concentration and 78 2% sugar consumption were obtained in the airlift bioreactor without sieve plates,62 9%,21 2mg/ml and 83 9% with one sieve plate,64 5%,21 3mg/ml and 81 4% with two sieve plates,respectively,which were all better than those in the mechanically stirred tank bioreactors.The results of experiments showed that the culture properties of the external loop airlift bioreactors were superior to those of the mechanically stirred bioreactor and being equipped with sieve plates in the airlift bioreactors could strengthen the productivity.