高酵母接种量的抑菌特性及其在蔗汁生产乙醇中的应用

研究了高酵母菌接种量的抑菌特性及对蔗汁乙醇发酵过程的影响。混合杂菌与酵母以不同浓度配比接入蔗汁发酵培养基中发酵,当增加酵母接种量达到5×10~7个/mL时,醪液中乙醇浓度没有明显降低。利用鲜甘蔗汁直接发酵时,接种量为5×10~7个/mL,乙醇产量达10.54%(20℃,v/v),与使用经高温灭菌的甘蔗汁作培养基,酵母接种量为2×10~7个/mL时相当,但发酵速度明显快于后者。其发酵上清液中未检出抑菌成分,说明提高酵母的接种量可以有效抑菌,其原因可能是酵母的生长处于竞争优势,抑制了杂菌的生长代谢。该研究为蔗汁发酵生产燃料乙醇,降低染菌风险提供了有效的尝试。     

固定化酵母R36酒精发酵工艺研究

对固定化酵母酒精发酵工艺进行研究,结果表明,最佳发酵条件为初始糖度28°Bx,固定化酵母接种量15mL,发酵温度36℃.在此条件下发酵52h发酵醪酒精度达到12.8％vol,糖的利用率90.27％,发酵效率达到86.7％.     

甜高粱茎秆生产燃料乙醇的研究

对甜高粱茎秆原料生产燃料乙醇的工艺条件、残渣综合利用等进行了研究,确定了甜高粱茎秆汁液发酵生产燃料乙醇的最佳工艺条件:高粱汁锤度为20°Bx(糖度17.8%)、接种量为10%、pH值4.5、发酵时间48h,发酵醪的酒精浓度可达10.2%以上,残糖1%以下.     

水稻秸秆同步糖化发酵生产燃料乙醇的研究

研究了培养基起始pH、发酵时间、发酵温度、酵母接种量和吐温80对水稻秸秆同步糖化发酵产乙醇的影响。结果表明,酵母接种量能有效地提高发酵液中乙醇的产率。水稻秸秆同步糖化发酵生产燃料乙醇的适宜发酵工艺条件为：起始pH值为4．0～4．5,培养温度为32℃,接种量为12％,发酵时间12-24h。在此条件下,生成乙醇的浓度为1．4mg／mL,水稻秸秆原料的乙醇转化率达7．02％。     

固定化酵母发酵产酒精载体选择的研究

以海藻酸钙和甘蔗块为载体固定酵母细胞,进行蔗汁和废糖蜜酒精发酵。结果表明,以甘蔗汁为发酵培养基时甘蔗块固定化酵母发酵液中平均残糖锤度(20℃)比海藻酸钙包埋酵母发酵低0.36,酒精平均体积分数比海藻酸钙包埋酵母发酵高0.20%;以废糖蜜为发酵培养基时甘蔗块固定化酵母发酵液中平均残糖锤度(20℃)比海藻酸钙包埋酵母发酵低0.43,酒精平均体积分数比海藻酸钙包埋酵母发酵高0.23%,显示出甘蔗块固定化法酵母发酵优于海藻酸钙包埋法固定化酵母。此外,甘蔗汁培养基与废糖蜜培养基对总体发酵效果的影响非常接近,但综合考虑甘蔗汁与废糖蜜的成本,废糖蜜是工业发酵生产乙醇用培养基的更优选择。     

固定化酵母的选育及在木薯浓醪发酵生产燃料乙醇中的性能对比

对固定化酵母进行选育,得到3株酿酒酵母编号分别为SLS、SYA、SJY和1株自絮凝酵母FJY。以木薯为原料,对固定化酵母浓醪发酵生产燃料乙醇的性能进行对比,结果表明,自絮凝酵母菌株FJY的乙醇生产能力最高,在发酵86 h后,最终酒精分达到15.7%vol,残总糖1.35%,甘油产量比其他3株酵母菌株低20%。     

固定化酵母的选育及在木薯浓醪发酵生产燃料乙醇中的性能对比

通过对固定化酵母的选育,得到三株酿酒酵母编号分别是SLS、SYA、SJY和一株自絮凝酵母FJY。以木薯为原料,对固定化酵母浓醪发酵生产燃料乙醇的性能进行对比,结果表明自絮凝酵母菌株FJY的乙醇生产能力最高,在发酵86h后,最终酒精分达到15.7%v/v,残总糖1.35%,甘油产量比其他三株酵母菌株低20%。     

运动发酵单孢菌发酵生产乙醇研究进展

运动发酵单孢菌与传统酵母相比具有发酵速率快、糖利用率高等优点．但发酵底物范围窄。其发酵过程的生物量与葡萄糖浓度和酵母膏添加量有重要关系。应用固定化、共固定化技术，多菌株混合发酵，或利用基因工程技术可提高运动发酵单孢菌的发酵产酒精性能。提高发酵产乙醇量。（孙悟）     

固定化菌种发酵生产金柑果醋的研究

以金柑为主要原料,利用固定化菌种进行发酵酿造金柑果醋的研究。实验结果表明利用固定化技术酿造金柑果醋的适宜工艺条件为酒精发酵阶段:糖度18%,固定化酵母菌接种量10%,接种发酵菌种中生香酵母与酿酒酵母的比例1∶1,发酵温度32℃,发酵时间72h;醋酸发酵阶段:起始酒精度8%,固定化醋酸菌接种量10%,醋酸发酵温度33℃,发酵时间72h。     

甜菜制燃料乙醇生产工艺的研究

以甜菜为原料,采用固定化酵母细胞发酵生产燃料乙醇.所得最佳工艺条件为培养液糖浓度为16%,硫酸铵0.5g/L,磷酸二氢钾0.08g/L,硫酸亚铁0.004g/L,α-淀粉酶用量为5U/g,糖化酶用量为150U/g,发酵液适宜pH值为4.5,固定化凝胶颗粒填装量为50%.发酵醪酒精度为12.3%vol,总糖利用率96.91%.     

Evaluation of ethanol fermentation parameters for bioethanol production from sugar beet pulp and juice

The aim of this study was to investigate the efficient utilization of sugar beet pulp, as well as raw, concentrated raw and thick sugar beet juice, for bioethanol production. Different fermentation conditions were examined. The influence of raw material pre‐treatment (pasteurization or sterilization), type of batch culture process (stationary or shaken) as well as the type of Saccharomyces cerevisiae yeast preparation on the yields of the process were studied. Moreover, the fermentation process effectiveness was examined in connection with the quality of the obtained distillates. Sterilization, stationary batch culture and Safdistil C‐70 yeast preparation were identified as the most profitable factors for sugar beet pulp fermentation, providing a high fermentation efficiency and ethanol yield (87.7% of theoretical ethanol yield). Concentrated raw beet juice resulted in a value of 94.2% of theoretical yield, and thick juice a 92.6% yield. The results suggest that bioethanol production from sugar beet pulp and sugar beet juice has promise as an alternative fuel. The raw spirits obtained from the sugar beet juice were characterized as having the lowest quantity of volatile by‐products. Copyright © 2014 The Institute of Brewing & Distilling     

甘蔗块固定化酵母的制备及其在蔗汁燃料乙醇生产中的应用

以甘蔗块为载体固定酵母细胞,通过优化载体大小和预处理方式,制备得到性能优良的固定化酵母,应用于蔗汁燃料乙醇的生产。研究结果表明,大量酵母细胞固定于甘蔗块内部空腔以及吸附于甘蔗块表面;较小的甘蔗茎块作为固定化载体,乙醇产率增加10%左右;冷冻储存的甘蔗块经过解冻、去木质素处理后固定酵母,以40%的装填率发酵36 h,乙醇浓度达99.34 g/L,糖利用率为99.23%,发酵效率为93.09%。     

High-temperature ethanol fermentation by immobilized coculture of Kluyveromyces marxianus and Saccharomyces cerevisiae

Suspended and immobilized cocultures of the thermotolerant yeast, Kluyveromyces marxianus DMKU 3-1042 and the mesophilic flocculent yeast, Saccharomyces cerevisiae M30 were studied for their abilities to improve production and stability of ethanol fermentation. Sugarcane juice and blackstrap molasses, at initial sugar concentrations of 220 g/L, were used as carbon sources. The results indicated that the coculture system could improve ethanol production from both sugarcane juice and blackstrap molasses when the operating temperature ranged between 33 °C and 45 °C. High temperature tolerances were achieved when the coculture was immobilized. The immobilized coculture was more effective in high-temperature ethanol fermentation than the suspended cultures. The coculture immobilized on thin-shell silk cocoon and fermented at 37 °C and 40 °C generated maximal ethanol concentrations of 81.4 and 77.3 g/L, respectively, which were 5.9-8.7% and 16.8-39.0% higher than those of the suspended cultures, respectively.     

甘蔗渣固定化酵母酿造百香果果酒的研究

以甘蔗渣为载体吸附固定酿酒酵母（Saccharomyces cerevisiae）YJSF190,并以游离酵母作为对照,采用固定化酵母酿造百香果果酒,比较两种酵母发酵果酒中的乙醇、残糖、有机酸和乙酸乙酯含量。结果表明,游离酵母酿造百香果果酒乙醇产量为96.36 g/L,乙醇产出速率为2.01 g/（L·h）,总残糖含量为5.14 g/L,乙酸乙酯含量为14.3 mg/L,乙酸、草酸、酒石酸、苹果酸、柠檬酸、琥珀酸含量分别为21.67 g/L、0.44 g/L、0.91 g/L、3.80 g/L、44.54 g/L、3.16 g/L;固定化酵母酿造果酒乙醇产量为98.22～124.37 g/L,乙醇产出速率为2.05～3.11 g/（L·h）,总残糖含量为3.62～4.09 g/L,乙酸乙酯含量为15.7～22.86 mg/L;乙酸、草酸、酒石酸、苹果酸、柠檬酸、琥珀酸含量分别为15.11～20.18 g/L、0.27～0.44 g/L、0.78～0.96 g/L、2.61～3.80 g/L、33.40～45.83 g/L、2.22～2.68 g/L。表明固定化酵母可应用于酿造百香果果酒。     

The Fermentation of Beet Sugar Syrup to Produce Bioethanol

Fermentation of sugar or starch‐containing substrates by yeast to produce ethanol for use as a liquid fuel has been an accepted technology for many years. Currently, the most popular substrates are sugar cane molasses and starch from maize or wheat. Interest in renewable liquid fuels is growing and other substrates are now being considered, choice of these depends on local conditions. This paper presents findings from work carried out on syrup from sugar beet, an ideal crop for cultivation in the United Kingdom and parts of Europe. Fermentation of this substrate was found to be successful. The process of backsetting was investigated as a way of reducing water usage and effluent disposal. This was found to have no effect on ethanol production provided compensation was made for increases in gravity caused by glycerol levels. Backsetting was also found to be beneficial to yeast growth. As yeast remain in the fermented substrate, the effect of distillation on yeast cells was also investigated. It was found that dead yeast cells are present in backset and thus persist into subsequent fermentations. This can cause difficulties in viability measurement if the methylene blue method is used.     

甘蔗生产燃料乙醇工艺探索与应用

以固定化酵母作为发酵菌株,研究了甘蔗生产燃料乙醇的预处理、发酵工艺。获得了最适工艺参数：甘蔗经切断、撕裂、压榨机压榨和板框过滤后得到甘蔗汁,在甘蔗汁中加入1 U/mL的青霉素,发酵及酒母培养的pH值为3.5～4.0,添加0.01%的硫酸镁。32～35℃,发酵21 h,乙醇浓度达到9.5%vol左右,糖醇转化率在96%左右。采用单浓度双流加连续发酵工艺进行生产试验,与淀粉质及纤维质燃料乙醇工艺进行对比,结果表明,甘蔗生产燃料乙醇的连续发酵工艺在生产上是完全可行的,工艺路线简单,生产成本低,是目前最适于大规模推广的燃料乙醇生产工艺。     

Ethanol production from carob pod extract by immobilized saccharomyces cerevisiae cells on the mineral kissiris

The production of ethanol from carob pod extract by immobilized S. cerevisiae cells on the mineral kissiris was investigated. The optimum conditions for carob pod extract fermentations were pH 3.5 ‐ 6.5, temperature 30°C and initial sugar concentration of 250g/l. A maximum ethanol concentration (64.5g/l), ethanol yield (28.3%) and sugar utilization (94%) was achieved at an initial sugar concentration of 250, 200 and 250g/l, respectively. In repeated batch fermentations, the immobilized S. cerevisiae cells on kissiris retained their ability to produce ethanol for 30 days.     

Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production

In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production.     

Bioethanol production from sugar beet molasses and thick juice by free and immobilised Saccharomyces cerevisiae

The aim of this study was the investigation and comparison of the potential of sugar beet molasses and thick juice as raw materials for bioethanol production, as renewable and sustainable energy sources. Ethanol fermentation of a wide range of initial sugar concentrations (100–300 g/L) was performed using either free or immobilised Saccharomyces cerevisiae in calcium alginate beads in the absence of any added nutrients. In general, immobilised cells showed better fermentative performance, enhanced ethanol productivity, stability and cell viability compared with free cells, under the same fermentation conditions. The high concentration of non‐sugar components contained in molasses affected yeast fermentation performance and viability. Maximum ethanol concentration in fermented media of 84.6 and 109.5 g/L were obtained by immobilised cells for initial sugar concentrations of 200 and 250 g/L for molasses and thick juice, respectively. However, the highest ethanol yields of 31.7 L per 100 kg of molasses and 37.6 L per 100 kg of thick juice were obtained by immobilised cells at an initial sugar concentration of 175 g/L. In the high gravity fermentation process, thick juice resulted in a higher ethanol yield per mass of raw material compared with molasses. This study shows the advantage of immobilised yeast for the efficient production of high gravity bioethanol from thick juice, which was a more favourable raw material than molasses. © 2018 The Institute of Brewing & Distilling