共查询到20条相似文献,搜索用时 750 毫秒
1.
为了客观评判耐高温东方伊萨酵母HN-1利用木质纤维素水解液生产燃料乙醇的潜力,本文采用单因素试验和响应面中心组合试验研究了木质纤维素水解液有毒副产物甲酸钠(1.0-5.0 g/L)、乙酸钠(2.5-8.0 g/L)、糠醛(0.2-2.0 g/L)、5-羟甲基糠醛(0.1-1.0 g/L)和香草醛(0.5-2.0 g/L)对其乙醇发酵的影响。结果表明,木质纤维素水解液有毒副产物对东方伊萨酵母HN-1乙醇发酵的影响较小,除添加2 g/L香草醛或添加1 g/L 5-羟甲基糠醛可使乙醇产量分别降低20.38%和11.2%外,其他抑制物的添加对乙醇的生成未有显著影响。但是,当副产物浓度较高时,可以显著抑制菌体生长,添加1-5 g/L甲酸钠、2.5-8.0 g/L乙酸钠、0.4-2 g/L糠醛或0.5-2 g/L香草醛,发酵36 h时菌体细胞干重分别较对照下降了25.04%-37.02%、28.83%-43.82%、20.06%-37.60%和26.39%-52.64%。中心组合试验结果表明各抑制物交互作用对乙醇的生成影响不显著。该研究表明木质纤维素水解液副产物对东方伊萨酵母HN-1乙醇发酵的影响较小,适合用于纤维乙醇发酵。 相似文献
2.
3.
稻草酶法水解液的丙酮丁醇发酵 总被引:9,自引:1,他引:9
利用丙酮丁醇梭菌C375菌株发酵稻草酶法水解液,分别研究了氮源、生长因子PH等因素对发酵的影响。结果表明,在稻草水解液还原糖浓度为4.28%时,总溶剂为12.8g/L,溶剂组成:丁醇:丙酮:乙醇=65.8:23.8:10.4,溶剂生成率为29.9%。 相似文献
4.
木糖是木质纤维素原料水解液中的第二大组分,木糖和葡萄糖的充分利用是有经济性地生产纤维素乙醇的关键。通过基因克隆手段构建了一株可以高效利用木糖产乙醇的重组运动发酵单胞菌Zymomonas mobilis TSH01,并进行了利用单糖溶液、混合糖溶液及玉米秸秆水解液发酵产乙醇效率的研究。结果表明,利用单一葡萄糖或单一木糖溶液发酵时,当糖浓度为8%、发酵72 h后,糖利用率分别为100%和98.9%,乙醇代谢收率分别为87.8%和78.3%;利用8%葡萄糖和8%木糖的混合溶液发酵时,72 h后,葡萄糖和木糖的利用率分别为98.5%和97.4%,乙醇代谢收率为94.9%。利用含3.2%葡萄糖和3.5%木糖的玉米秸秆水解液发酵72 h后,葡萄糖和木糖的利用率分别为100%和92.3%,乙醇代谢收率为91.5%。此外,磷酸二氢钾对发酵过程中木糖利用率以及乙醇收率的提高有明显促进作用。 相似文献
5.
6.
7.
8.
张东旭 《中国生物工程杂志》2013,33(5):120-124
实现从木质纤维素原料到燃料和高附加值化学品的生物转化,预处理是一个非常重要的步骤.酸解或蒸汽爆破等热-化学预处理过程会在水解液中生成或释放有机酸类、糠醛类和酚类化合物等抑制因子.这些抑制因子对发酵微生物具有毒性,会显著降低发酵产品的产率和生产强度.生物法去除木质纤维素水解液中的抑制因子具有操作简便以及不产生废水、废物等优点.生物脱毒法可分为两类:一类是通过向木质纤维素水解液中添加微生物或酶制剂,在发酵前去除抑制因子;另一类方法是通过遗传改造或适应性进化提高发酵菌株对抑制因子的生物降解能力,从而提高木质纤维素水解液的发酵性能.将着重以乙醇生产为例,介绍如何通过生物脱毒的方法提高木质纤维素水解液发酵的得率和生产强度. 相似文献
9.
对提取维生素B12后的费氏丙酸杆菌废菌体进行水解处理,考察以菌体水解液作为N源用于丙酸发酵的可行性.利用正交设计得到了提取维生素B12后的废菌体水解优化条件.基于此,构建利用植物纤维床反应器固定化生产丙酸联产维生素B12的低成本绿色循环工艺.结果表明:在4.5L的发酵体系中,单批次总糖质量浓度为200 g/L,发酵进行了5批次共1192h,丙酸生成总量为2 328.75 g,单批次丙酸质量浓度103.50 g/L,丙酸生产效率达0.43 g/(L·h),干菌质量浓度达到19.52 g/L.将菌体注入微好氧发酵罐中发酵获得112.8 mg/L维生素B12. 相似文献
10.
为提高嗜热厌氧菌T.calidifontis Rx1的乙醇产率,通过同源重组的方式敲除Rx1乙酸生成途径的乙酸激酶(ack)基因,得到了代谢工程菌Δack突变株。分别以葡萄糖、纤维二糖、木糖和玉米芯酸水解液为底物,研究突变菌株的底物利用、细胞生长和发酵产物的变化情况。结果表明,与野生菌株相比,突变菌株的干重都有所降低,但是乳酸或乙醇的得率显著提高;当以纤维二糖为底物时,突变菌株的乙醇产量达3.60g/L,得率为0.55g/g,远高于突变菌株对其它底物的产量;以玉米芯水解液为底物时,突变菌株的乳酸产量高于野生菌株,而且野生菌乳酸、乙醇的产量都高于以木糖为底物时的产量。 相似文献
11.
Zhang YH 《Journal of industrial microbiology & biotechnology》2008,35(5):367-375
Before the industrial revolution, the global economy was largely based on living carbon from plants. Now the economy is mainly
dependent on fossil fuels (dead carbon). Biomass is the only sustainable bioresource that can provide sufficient transportation
fuels and renewable materials at the same time. Cellulosic ethanol production from less costly and most abundant lignocellulose
is confronted with three main obstacles: (1) high processing costs ($/gallon of ethanol), (2) huge capital investment ($∼4–10/gallon
of annual ethanol production capacity), and (3) a narrow margin between feedstock and product prices. Both lignocellulose
fractionation technology and effective co-utilization of acetic acid, lignin and hemicellulose will be vital to the realization
of profitable lignocellulose biorefineries, since co-product revenues would increase the margin up to 6.2-fold, where all
purified lignocellulose co-components have higher selling prices (>∼1.0/kg) than ethanol (∼0.5/kg of ethanol). Isolation of
large amounts of lignocellulose components through lignocellulose fractionation would stimulate R&D in lignin and hemicellulose
applications, as well as promote new markets for lignin- and hemicellulose-derivative products. Lignocellulose resource would
be sufficient to replace significant fractionations (e.g., 30%) of transportation fuels through liquid biofuels, internal
combustion engines in the short term, and would provide 100% transportation fuels by sugar–hydrogen–fuel cell systems in the
long term.
JIMB-2008: BioEnergy—Special issue. 相似文献
12.
利用木糖-葡萄糖为原料产乙醇酵母的筛选、鉴定及发酵试验 总被引:1,自引:0,他引:1
建立筛选利用木糖为碳源产乙醇酵母模型,获得一株适合利用木质纤维素为原料产乙醇的酵母菌株。样品经麦芽汁培养基培养后,以木糖为唯一碳源的筛选培养基初筛,再以重铬酸钾显色法复筛。通过生理生化和26D1/D2区对筛选得到的菌株进行分析和鉴定,该菌初步鉴定为Pichia caribbica。经过筛选得到的菌株Y2-3以木糖(40g/L)为唯一碳源发酵时:生物量为23.5g/L,木糖利用率为94.7 %,乙醇终产量为4.57 g/L;以混合糖(葡萄糖40 g/L,木糖20 g/L)发酵时:生物量为28.6 g/L,木糖利用率为94.2 %,葡萄糖利用率为95.6%,乙醇终产量为20.6 g/L。Pichia caribbica是可以转化木糖及木糖-葡萄糖混合糖为乙醇的酵母菌株,为利用木质纤维素发酵乙醇的进一步研究奠定了基础。 相似文献
13.
木质纤维素原料酶水解产乙醇工艺的研究进展 总被引:2,自引:1,他引:1
木质纤维素原料预处理后,经水解、发酵等过程,可生产乙醇作为清洁燃料,这大大提高了农业和林业废弃物的利用率,减轻了环境污染,并为经济的可持续发展提供了保证。目前木质纤维素酶水解因其具有明显优势而受到重视,被普遍研究和采用。综述了近年来木质纤维素原料的预处理方法、酶与水解技术、发酵工艺以及发酵耦合分离技术的最新研究成果。 相似文献
14.
15.
16.
产乙醇工程菌研究进展 总被引:1,自引:1,他引:1
伴随着21世纪的到来,低油价的时代也悄然落幕。简要概述了燃料乙醇产生菌代谢工程的研究进展,包括了利用淀粉、戊糖及纤维素的工程酵母构建,运动发酵单胞菌利用戊糖工程菌的构建,引入外源乙醇合成途径的大肠埃希氏菌和产酸克雷伯氏菌等。对燃料乙醇的重视将促进开发能利用廉价原料和要求粗放的工程菌株用于高产乙醇的生产过程,以降低成本和能耗,其中能利用生淀粉的工程酵母及利用木质纤维素水解物的运动发酵单胞菌工程菌有较大的工业化潜力。 相似文献
17.
Yuqing Zhang Xuemin Xu Yuyuan Zhang Jianfa Li 《Biotechnology and Bioprocess Engineering》2011,16(5):930-936
Fuel ethanol is one of the most important alternative fuels used as a substitute for fossil fuel. Lignocellulose is the most
abundant biomass resource for the production of fuel ethanol. However, the hydrolysis of lignocellulose requires high enzyme
loading. In order to strengthen the process of enzyme hydrolysis of lignocellulose, surfactant-polyethylene glycol (PEG) was
applied to the catalysis of lignocellulose into fermentable sugars. The effect of PEG on both the enzymatic hydrolysis and
adsorption of cellulose were investigated. The addition of surfactant obviously facilitated enzymatic hydrolysis. In particular,
upon addition of PEG4000, the enzyme catalytic efficiency increased by 51.06%. Meanwhile, the adsorption quantity of cellulase
decreased by 11.25%. In addition, the mechanism of the effect of PEG on enzymatic hydrolysis and cellulase adsorption is discussed. 相似文献
18.
Degradation of lignocellulose with pressurised hot water is an efficient method of bioethanol production. However, the resultant
solution inhibits ethanol fermentation by Saccharomyces cerevisiae. Here, we first report that glycolaldehyde, which is formed when lignocellulose is treated with pressurised hot water, inhibits
ethanol fermentation. The final concentration of glycolaldehyde formed by the treatment of lignocellulose with pressurised
hot water ranges from 1 to 24 mM, and 1–10 mM glycolaldehyde was sufficient to inhibit fermentation. This result indicates
that glycolaldehyde is one of the main substances responsible for inhibiting fermentation after pressurised hot water degradation
of lignocellulose. Genome-wide screening of S. cerevisiae revealed that genes encoding alcohol dehydrogenase, methylglyoxal reductase, polysomes, and the ubiquitin ligase complex
are required for glycolaldehyde tolerance. These novel findings will provide new perspectives on breeding yeast for bioethanol
production from biomass treated with pressurised hot water. 相似文献
19.
The search for petroleum alternatives has motivated intense research into biological breakdown of lignocellulose to produce
liquid fuels such as ethanol. Degradation of lignocellulose for biofuel production is a difficult process which is limited
by, among other factors, the recalcitrance of lignocellulose and biological toxicity of the products. Consolidated bioprocessing
has been suggested as an efficient and economical method of producing low value products from lignocellulose; however, it
is not clear whether this would be accomplished more efficiently with a single organism or community of organisms. This review
highlights examples of mixtures of microbes in the context of conceptual models for developing symbiotic consortia for biofuel
production from lignocellulose. Engineering a symbiosis within consortia is a putative means of improving both process efficiency
and stability relative to monoculture. Because microbes often interact and exist attached to surfaces, quorum sensing and
biofilm formation are also discussed in terms of consortia development and stability. An engineered, symbiotic culture of
multiple organisms may be a means of assembling a novel combination of metabolic capabilities that can efficiently produce
biofuel from lignocellulose. 相似文献
20.
木质纤维素是生产生物燃料乙醇的主要原料,其含量丰富、绿色环保以及可再生性,因此有效地利用木质纤维素有望解决能源短缺问题。表面活性剂能够有效地促进木质纤维素的酶解反应,通过探讨不同表面活性剂对酶解反应的影响及机理,为实际的酶解过程找到合适表面活性剂提供一定的理论指导。 相似文献