絮凝酵母乙醇连续发酵耦合菌体回用工艺及非粮原料利用
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摘要
模拟现有乙醇发酵行业普遍采用的多级串联机械搅拌式反应器,建立了一套由三级串联操作的搅拌式发酵罐和两个沉降罐组成的反应器系统,以脱胚脱皮玉米粉双酶法制备的糖化液为发酵底物,初始还原糖浓度为220g/L,添加(NH_4)_2HPO_4 1.5g/L和KH_2PO_42.5g/L,以0.057 h~(-1)的恒定稀释速率流加,将沉降浓缩后的酵母先后经活化和不活化两种方式全部回用至首级发酵罐,系统分别在两种操作条件下达到了拟稳态。实验结果表明:活化处理在提高酵母回用工艺的发酵指标方面发挥了显著的作用,发酵终点乙醇浓度达到101g/L,残还原糖和总糖分别在3.2和7.7g/L左右,发酵系统的设备生产强度指标为5.77g L~(-1)h~(-1),与无酵母回用的搅拌式反应器系统中自絮凝颗粒酵母乙醇发酵工艺相比,提高了70%。
在玉米原料自絮凝颗粒酵母SPSC01酒精发酵工艺技术已经取得成功的基础上,为进一步开发该菌株酒精发酵的原料领域,提升我国两广地区酒精发酵的工艺技术水平,实验进一步系统研究了以木薯粉和甘蔗糖蜜为原料的酒精发酵特性,摸索出合适的发酵工艺指标:以二次脱皮木薯粉双酶法制备的糖化液为发酵底物时,初始还原糖浓度为220g/L,添加(NH_4)_2HPO_4 5g/L和KH_2PO_4 1.55g/L,以0.036 h~(-1)的恒定稀释速率流加,系统稳定后发酵终点乙醇浓度达到106.4g/L,残余葡萄糖、还原糖和总糖分别稳定在0.08、6.1和17g/L左右,发酵系统的设备生产强度指标为3.83 g L~(-1)h~(-1);以废糖蜜为原料经过酸化稀释灭菌等处理后控制初始还原糖浓度为190g/L,添加KH_2PO_4 2g/L,以0.05 h~(-1)的恒定稀释速率流加,系统稳定后发酵终点的平均酒精浓度达到81 g/L,残还原糖浓度降为35g/L以下,计算得设备生产强度为4.05 g L~(-1)h~(-1)。
A continuous ethanol fermentation system composed of three-stage tank fermentors in series coupled with two sediment tanks was established. A self-flocculating yeast strain developed by protoplast fusion of Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage corn powder enzymatic hydrolyzate containing reducing sugar 220 g/L, together with 1.5 g/L (NH_4)_2HPO_4 and 2.5 g/L KH_2PO_4, was used as ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057 h~(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor in two ways, respectively, activation-recycle and direct recycle. The relatively chemostat-states were obtained for both operations. Activation process was found necessary for maintaining a good ethanol fermentation performance at the high dilution rate. The broth containing 101 g/L ethanol and 3.2 g/L residual reducing sugar and 7.7 g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77 g L~(-1) h~(-1), which increased more than 70% compared with that for continuous ethanol fermentation in tank fermentors without recycling of yeast cells using the same yeast strain.Based on the achievement of corn powder material, the new extension study on cassava and cane molasses, which are abundant in south of China, was developed respectively: Two-stage cassava powder enzymatic hydrolyzate containing reducing sugar 220 g/L, together with 5.0g/L (NH_4)__2HPO_4 and 1.55 g/L KH_2PO_4, was used as ethanol fermentation substrate and fed into the first fermentor of three-stage fermentors system at the dilution rate of 0.036 h~(-1), the relatively chemostat-state was obtained and the broth containing more than 106.4 g/L ethanol and 6.1 g/L residual reducing sugar and 17 g/L residual total sugar was produced. The ethanol productivity was calculated to be 3.83 g L~(-1)h~(-1);multi-stage treated cane molasses diluent containing reducing sugar 190 g/L, together with 2 g/L (NH_4)_2HPO_4 was used as ethanol fermentation substrate and the broth containing more than 81 g/L ethanol and 35 g/L residual reducing sugar, the ethanol productivity was calculated to be 4.05 g L~(-1) h~(-1).
在玉米原料自絮凝颗粒酵母SPSC01酒精发酵工艺技术已经取得成功的基础上,为进一步开发该菌株酒精发酵的原料领域,提升我国两广地区酒精发酵的工艺技术水平,实验进一步系统研究了以木薯粉和甘蔗糖蜜为原料的酒精发酵特性,摸索出合适的发酵工艺指标:以二次脱皮木薯粉双酶法制备的糖化液为发酵底物时,初始还原糖浓度为220g/L,添加(NH_4)_2HPO_4 5g/L和KH_2PO_4 1.55g/L,以0.036 h~(-1)的恒定稀释速率流加,系统稳定后发酵终点乙醇浓度达到106.4g/L,残余葡萄糖、还原糖和总糖分别稳定在0.08、6.1和17g/L左右,发酵系统的设备生产强度指标为3.83 g L~(-1)h~(-1);以废糖蜜为原料经过酸化稀释灭菌等处理后控制初始还原糖浓度为190g/L,添加KH_2PO_4 2g/L,以0.05 h~(-1)的恒定稀释速率流加,系统稳定后发酵终点的平均酒精浓度达到81 g/L,残还原糖浓度降为35g/L以下,计算得设备生产强度为4.05 g L~(-1)h~(-1)。
A continuous ethanol fermentation system composed of three-stage tank fermentors in series coupled with two sediment tanks was established. A self-flocculating yeast strain developed by protoplast fusion of Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage corn powder enzymatic hydrolyzate containing reducing sugar 220 g/L, together with 1.5 g/L (NH_4)_2HPO_4 and 2.5 g/L KH_2PO_4, was used as ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057 h~(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor in two ways, respectively, activation-recycle and direct recycle. The relatively chemostat-states were obtained for both operations. Activation process was found necessary for maintaining a good ethanol fermentation performance at the high dilution rate. The broth containing 101 g/L ethanol and 3.2 g/L residual reducing sugar and 7.7 g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77 g L~(-1) h~(-1), which increased more than 70% compared with that for continuous ethanol fermentation in tank fermentors without recycling of yeast cells using the same yeast strain.Based on the achievement of corn powder material, the new extension study on cassava and cane molasses, which are abundant in south of China, was developed respectively: Two-stage cassava powder enzymatic hydrolyzate containing reducing sugar 220 g/L, together with 5.0g/L (NH_4)__2HPO_4 and 1.55 g/L KH_2PO_4, was used as ethanol fermentation substrate and fed into the first fermentor of three-stage fermentors system at the dilution rate of 0.036 h~(-1), the relatively chemostat-state was obtained and the broth containing more than 106.4 g/L ethanol and 6.1 g/L residual reducing sugar and 17 g/L residual total sugar was produced. The ethanol productivity was calculated to be 3.83 g L~(-1)h~(-1);multi-stage treated cane molasses diluent containing reducing sugar 190 g/L, together with 2 g/L (NH_4)_2HPO_4 was used as ethanol fermentation substrate and the broth containing more than 81 g/L ethanol and 35 g/L residual reducing sugar, the ethanol productivity was calculated to be 4.05 g L~(-1) h~(-1).
引文
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[5] 李传林,鞠京丽.应用浓醪发酵技术,推动乙醇工业节能及清洁生产.酿酒科技.2005,5(2):115～120.
[6] 黄治玲,秦金来.燃料乙醇的生产与利用.化工科技.2003,11(4):44～47.
[7] 刘传斌,白凤武,邵梅等.自絮凝颗粒酵母乙醇高浓度连续发酵的研究.微生物学报.2001,41(3):367～371.
[8] 白凤武,云战友,谢健等.以玉米为原料采用絮凝颗粒酵母连续发酵新技术生产乙醇并副产SCP饲料工艺的探讨.食品与发酵工业.1994(3):60～65.
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[10] Wheal Alan E, Basso Luiz C, Alves Denise M G, et al. Fuel ethanol after 25 years. Trends Biotechnol. 1999.17(12): 482～487.
[11] 秦耀宗.乙醇工艺学.北京:中国轻工业出版社.1998.
[12] 刘波,夏友书,张英.细菌发酵制乙醇技术的研究现状综述.四川食品与发酵.2004,40(1):52～53.
[13] 魏华,韩德奇.大米挤压膨化对传统乙醇发酵的影.食品与发酵工业.1995,1:8～12.
[14] 马云,邹东辉.渗透汽化膜分离乙醇水溶液的研究.南京经济学院学报.1997(4):59～63.
[15] 吕仪军.发酵法生产乙醇技术进展.四川化工与腐蚀控制.1999(4):51～53.
[16] T.K. Ghose, Rosslyn, M.Birch. Simultaneous saccharification and fermentation (SSF) of lignocellulosics to ethanol under vacuum cycling and step feeding. Biotechnol. Bioeng. 1984, (26):377～381.
[17] 管斌.高强度乙醇连续发酵.生物技术.1997,7(4):38～41.
[18] 冯学愚,段俊英.强制循环发酵液的乙醇发酵研究.四川轻化工学院学报.1994,7(3):40～43.
[19] 秦庆军,高峻.发酵法生产乙醇研究进展.化工进展.1998,5:373～377.
[20] M.J. Nunez, M.Fernanda Rosa. Cell immobilization: Application to alcohol production. Enzyme Microb. Technol. 1987, 9: 642～651.
[21] Kida K, Yamadaki M, Asano S, et al. The effect of aeration on stability of continuous ethanol fermentation by a flocculating yeast. J. Ferment. Bioeng, 1989, 68: 107～111.
[22] Kuriyama H, Ishibashi H, Miyagawa H, et al. Cell immobilization: Application to alcohol production. Biotechnol Let. 1993,15(4):415～420.
[23] 云战友,谢健,白凤武等.全面认识谷物原料清液发酵生产乙醇.食品与发酵工业.1998,24(1):67～69.
[24] 谢健,白凤武,邵梅等.自絮凝酵母颗粒连续发酵生产乙醇的新工艺.微生物学报.1999,39(4):44～47.
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