不同溶氧控制方式下的谷胱甘肽分批发酵过程分析

分析了产朊假丝酵母生产谷胱甘肽（GSH）的摇瓶发酵过程,发现溶氧浓度的大小成为影响细胞生长和GSH产量的重要因素。在此基础上,研究了恒溶氧和恒转速条件下的GSH分批发酵过程,与恒转速发酵相比,恒溶氧控制发酵可以明显提高细胞干重和GSH产量,当恒溶氧浓度为35%时,二者的提高幅度最多可分别达到22%和30%。最后分别采用发酵动力学模型和代谢网络中各代谢物通量的分布情况对该结果产生的原因进行了定量解释。     

发酵抑制物对葡萄糖发酵产乙醇的影响

在纤维素乙醇研究中,木质纤维原料在酸性预处理过程中会产生甲酸、乙酸、乙酰丙酸、糠醛和5-羟甲基糠醛等发酵抑制物,这些发酵抑制物会影响葡萄糖发酵生产乙醇的收率。本文考察了发酵液中各种发酵抑制物含量对高温超级酿酒酵母发酵乙醇收率的影响。研究结果表明,多种发酵抑制物的协同作用对乙醇发酵的影响要高于单一种类发酵抑制物对乙醇发酵的影响。发酵液中发酵抑制物总量一般控制在3.0g/L以内时,对葡萄糖发酵生产乙醇的抑制作用不明显。     

高密度发酵在酒精生产中的应用进展

酒精不仅是重要的可再生能源,在食品、化工、医药等领域应用也极其广泛。高密度发酵（HCDF）能有效提高酒精产率降低能耗及废液排放,极具应用潜力。本文针对目前淀粉质原料HCDF中酵母选育、培养条件优化、工艺过程优化同步耦合及动力学模型的多元统计控制,综合分析了神经交叉网络-模糊控制和基于经验的实验系统等国内外最新进展,旨在为HCDF酒精生产工艺的进一步研究提供参考依据。     

The economics of ethanol production by extractive fermentation

Extractive fermentation is a processing strategy in which reaction and recovery occur simultaneously in a fermentation vessel through the use of a water-immiscible solvent which selectively removes an inhibitory product. We have developed an ethanol extractive fermentation process incorporating continuous operation, the ability to ferment concentrated feedstocks, and greatly reduced energy and water use. This article provides a detailed economic assessment of this process relative to current technology for an annual capacity of 100 million litres of ethanol. Extractive fermentation provides significant economic advantages for both grass roots and retrofitted plants. Producing anhydrous ethanol without distillation is a prospect.     

Development of a new cleaner production process for cassava ethanol

A new cleaner production process for cassava ethanol has been developed, in which the thin stillage by-product was treated initially by anaerobic digestion, and the digestate further processed by hydrogen-form cation exchange resin before being recycled as process water to make mash for the next ethanol fermentation batch. Thuswastewaterwas eliminated and freshwater and energy consumptionwas significantly reduced. To evaluate the new process, ten consecutive batches of ethanol fermentation and anaerobic digestion at lab scale were carried out. Average ethanol production in the recycling batches was 11.43% (v/v) which was similar to the first batch,where deionized (DI)waterwas used as process water. The chemical oxygen demand (COD) removal rate reached 98% and the methane yield was 322 ml per gramof COD removed, suggesting an efficient and stable operation of the anaerobic digestion. In conclusion, the application of the new process can contribute to sustainable development of the cassava ethanol industry.     

产甘油假丝酵母反复分批发酵法生产甘油

研究了合成培养基和复合培养基中产甘油假丝酵母反复分批发酵法生产甘油。结果表明,当产甘油假丝酵母细胞在贫磷合成培养基、贫磷复合培养基和补充微量元素的贫磷复合培养基中分别回用13次、9次和14次时,甘油平均产量（或平均得率）的增量均超过15.0%,而甘油平均产率的增加达到37.0%以上。因此限制反复分批发酵培养基中磷含量有利于增强产甘油假丝酵母细胞合成甘油的能力。产甘油假丝酵母细胞在贫磷复合培养基中的回用次数少于贫磷合成培养基中的回用次数,其原因是贫磷合成培养基仅限制了磷源的用量,而贫磷复合培养基除限磷外,微量元素缺乏使菌体生长和甘油生产能力受到影响,回用次数减少。与传统分批发酵相比,产甘油假丝酵母反复分批发酵具有发酵周期短、不需反复培养种子、节省原料成本、形成副产物少以及节约能源动力消耗等优点,可以实现甘油高产量、高得率和高产率的相对统一,且易于放大到工业化生产水平。     

Ethanol fermentation by Z. mobilis ATCC10988 in repeated batch cultures

Repeated-batch fermentations of glucose to ethanol by Z. mobilis (ATCC 10988) were examined in two semi-defined nutrient media. The measurement of acid produced by the microorganism was used to study its transient fermentation characteristics. An examination of the inhibitory effect of ethanol in repeated-batch fermentations supports an earlier finding on the presence of a ‘slow-acting inhibitory mechanism’ at high ethanol concentration in Z. mobilis (ATCC 10988) cultures. The experimental results also suggest that both microbially produced and exogeneously added ethanol have similar inhibitory effects on the fermentation behavior of this bacterium.     

合成气生物发酵法制乙醇的研究进展

采用合成气生物发酵法制乙醇具有反应条件温和、产物选择性高、原料来源广泛、低碳可持续发展等优势,是一种具有前景的可再生能源新型生产工艺。文章综述了合成气发酵法制乙醇的微生物种类及对应的适宜操作条件,分析了合成气发酵法制乙醇的Wood-Ljungdahl代谢途径;总结了合成气的广泛来源;分析讨论了过程工艺参数如合成气组成及压力、pH、温度、培养基组分、气液传质对合成气发酵的影响;指出合成气发酵法制乙醇面临的底物传质性能差、乙醇收率低等关键问题,比较了典型反应器在传质方面的差异,归纳了传质强化方法;总结了合成气发酵法制乙醇的工业化进展, 并提出了未来的发展方向。     

合成气生物发酵法制乙醇的研究进展

采用合成气生物发酵法制乙醇具有反应条件温和、产物选择性高、原料来源广泛、低碳可持续发展等优势,是一种具有前景的可再生能源新型生产工艺。文章综述了合成气发酵法制乙醇的微生物种类及对应的适宜操作条件,分析了合成气发酵法制乙醇的Wood-Ljungdahl代谢途径;总结了合成气的广泛来源;分析讨论了过程工艺参数如合成气组成及压力、pH、温度、培养基组分、气液传质对合成气发酵的影响;指出合成气发酵法制乙醇面临的底物传质性能差、乙醇收率低等关键问题,比较了典型反应器在传质方面的差异,归纳了传质强化方法;总结了合成气发酵法制乙醇的工业化进展, 并提出了未来的发展方向。     

提高发酵过程乙醇分离效率的新型反应器

设计了一种新型的带侧臂循环的气升式反应器,该反应器可以有效地把真空闪蒸发酵和汽提发酵2项技术结合起来。实验结果表明,与单独的汽提和闪蒸过程相比,利用此反应器进行同步汽提闪蒸操作,大大提高了乙醇的移出效率,从而进一步提高了发酵强度。     

Novel repeated batch operation for flash fermentation system: Experimental data and mathematical modelling

A novel repeated batch operation mode was proposed for ethanol fermentation, where the fermenter beer was periodically exchanged between the fermenter with biomass recycle and the distillation unit, to promote the selective removal of ethanol. Using the mathematical model developed, as based on the experimental results, the optimal operation of the proposed method was shown to attain high performance, with a productivity of about 12 g dm⁻³ h⁻¹ and a product concentration of 400 g dm⁻³.     

基于高密度培养的反复分批发酵法生产丁二酸

引言丁二酸俗称琥珀酸,是三羧酸循环的中间代谢产物和厌氧代谢的终端还原产物,广泛存在于动物、植物及微生物体内。作为重要的C4平台化合物,丁二酸可用于多种大宗化学品以及生物可降解材料的制备。利用微生物发酵生产丁二酸,由于     

稻谷生料发酵生产乙醇研究

提出在南方应以稻谷为原料进行燃料乙醇的开发。并对稻谷生料发酵进行了详细的实验研究,获得的最佳工艺条件为糖化酶200 U/g,果胶酶5 U/g,纤维素酶10 U/g,酸性蛋白酶10 U/g,加水比1.8∶1。发现植酸酶对稻谷生料发酵有促进作用。通过对发酵过程的分析,发现残余还原糖一直处于低水平,表明生料发酵工艺具有自身避免染菌的优势。实验表明,稻谷生料发酵工艺简单,原料利用率和醪液酒精体积分数均超过传统工艺。     

乙醇连续发酵与膜超滤耦合过程研究

采用ＣＡ－Ｔｉ复合管式膜组件与发酵耦合操作，用啤酒酵母从葡萄糖连续发酵乙醇是一个从不稳态到稳态的过程。其稳态的最佳操作参数为：初始葡萄糖浓度１４０ｇ／Ｌ，稀释率０．３ｈ~（－１），轴出比０．６３８，相应的细胞浓度２×１０~９ｃｅｌｌ／ｍＬ，葡萄糖利用率９２％，生产率２２ｇ／（Ｌ·ｈ）。当细胞浓度增加到一定程度时，乙醇生产率和酵母比生长速率的增长减缓。反应器中细胞的浓度由稀释率和轴出比决定。     

Detoxification and concentration of corn stover hydrolysate and its fermentation for ethanol production

Environmental and energy concerns have increased interest in renewable energy sources, particularly biofuels. Thus the fermentation of glucose from sulfuric acid-hydrolyzed corn stover for the production of bioethanol has been explored using a combined acid retardation and continuous-effect membrane distillation treatment process. This process resulted in the separation of the sugars and acids from the acid-catalyzed hydrolysate, the removal of most of the fermentation inhibitors from the hydrolysate and the concentration of the detoxified hydrolysate. The recovery rate of glucose from the sugar-acid mixture using acid retardation was greater than 99.12% and the sulfuric acid was completely recovered from the hydrolysate. When the treated com stover hydrolysate, containing 100 g/L glucose, was used as a carbon source, 43.06 g/L of ethanol was produced with a productivity of 1.79 g/(L· h) and a yield of 86.31 %, In the control experiment, where glucose was used as the carbon source these values were 1.97 g/(L·h) and 93.10% respectively. Thus the integration of acid retardation and a continuous-effect membrane distillation process are effective for the production of fuel ethanol from com stover.     

乙醇发酵过程模型及模拟优化研究进展

综述了乙醇发酵模型及模拟方面的研究,总结了各种模型的特点以及模拟的难点.Monod方程能较好地描述乙醇发酵的各种竞争性抑制作用,模拟的难点在于模型的优化求解;反应器中的乙醇发酵模型包括传质模型,模拟的难点在于采用总传质系数简化求解过程,并涉及非稳态平衡计算;纤维素发酵是大量制取廉价乙醇的方向,发酵模型中需综合考虑酶解、发酵及抑制作用等,模拟计算过程复杂.结果说明,对发酵过程进行模拟优化,是降低乙醇生产成本、促进乙醇大规模工业化生产的有效途径.提出乙醇发酵模型模拟方面的发展方向为:解决纤维素发酵的关键问题,并形成应用软件,有利于后续工业化中的优化控制等过程.     

Extraction of phospholipids from canola with supercritical carbon dioxide and ethanol

The potential use of supercritical (SC)-CO₂/ethanol mixture for the extraction and fractionation of phospholipids (PL) from flaked canola seeds, canola meal, and acetone insolubles (AI) was investigated. PL extraction was possible when ethanol was used as a cosolvent in SC-CO₂. PL recovery of 20.8% was achieved when canola flakes were extracted at 70°C and 55.2 MPa with SC-CO₂/10%EtOH after iol removal with neat SC-CO₂. Soaking of canola meal with ethanol prior to SC-CO₂/EtOH extraction increased PL recovery to 30.4%. PL content of the extracts increased with decreasing triglyceride concentration in the feed material and increasing amounts of ethanol added to SC-CO₂ or used for soaking. Fractionation of Al gums resulted in extracts containing 50% PL, of which 90% was phosphatidylcholine (PC); but yields were low, even after soaking treatment, due to caking. SC-CO₂/EtOH mixture may be used to extract PC-enriched PL from flaked canola seeds, canola meal, and AI. However, further research is needed to improve extraction efficiency.     

燃料乙醇装置仿真培训系统的开发

在吉林兴建的燃料乙醇装置,具有年生产能力大、生产工艺复杂、自动化水平高等特点,又是国内首家,工艺过程没有同行可借鉴,因此,装置开车前的计算机仿真培训是保证正常开车的必要条件。计算机仿真培训是借助于多媒体计算机设备和仿真软件而进行的一种以实际操作技能为主的培训方式,全面介绍了燃料乙醇仿真系统软、硬件的结构,着重阐明设计思想和技术特色;实现了全流程的仿真;该系统既可用于培训,还可用于运行指导。     

酒精发酵中杀菌剂的研究进展

酒精发酵是一个非常复杂的微生物反应过程.在这个过程中,除了生产菌外,还会从原料、空气、水等带入相当数量的杂菌,从而降低酒精得率,影响酒精的正常生产.因此如何有效控制杂菌的感染,对整个酒精生产至关重要.本文综述了酒精发酵中杀菌剂的研究进展,主要介绍了酒精发酵过程中染菌的原因、危害、检测方法以及常见的污染杂菌,重点介绍了漂白粉、青霉素、克菌灵、酒花及植物提取物等杀菌剂的使用.指出减少酒精发酵中的杂菌污染,加强细菌抗药性的研究,寻找安全天然杀菌剂替代品是未来研究的关键.     

高底物浓度纤维乙醇同步糖化发酵工艺的比较

引言日益加剧的能源危机和环境污染,正迫使人们寻求新的可再生替代能源。纤维乙醇作为一种重要的生物质替代能源,经过近40多年的发展,已经具备了实现工业化生产的潜力。为了进一步降低纤