厌氧菌发酵生物制氢技术试验分析

人类在面临、解决环境和能源危机问题上,研究了很多的方法。为更好地解决回收能源的问题,通过采用生物制氢技术就可以大量净化有机废弃物,这种能源利用的方法比较符合可持续发展的国家战略和经济的政策。厌氧发酵生物制氢技术可以实现如废物处理资源化,它稳定性好、产氢能力高,可以应用于对少数几种符合化合物以及单一化合物的研究,此技术拥有广泛的利用基质。如今,我国食品行业中发展最迅速的要数饮料行业,果汁饮料废水含糖量高的特点给厌氧发酵产氢提供良好的条件。文章分析了厌氧发酵生物制氢的影响因素以及在应用方面的缺点,作为一种具备极大潜力的新能源技术,围绕厌氧菌发酵生物制氢技术进行探讨。     

利用CSTR生物制氢系统厌氧发酵的研究现状

生物制氢技术在开发能源方面具有重要的现实地位,连续流搅拌槽式反应系统（CSTR）采用机械搅拌,传质效率高,可有效提高产氢效率,同时此设备技术要求较为简单,能大幅降低生物制氢的成本,易于实现氢气的工业化生产.本文阐述了连续流搅拌槽式反应器（CSTR）生物制氢系统的研究进展,着重剖析了CSTR生物制氢系统的影响因素、底物范围和相关的技术研究,并对其发展和实际应用进行了简要论述.     

利用UASB反应器厌氧发酵糖厂废水生物制氢的研究进展

介绍了糖厂废水利用上流式厌氧污泥床（UASB）反应器进行厌氧发酵制氢的原理、工程控制参数,重点阐述了其研究现状和发展趋势.利用UASB反应器进行生物制氢,在理论研究方面已取得许多成果,但仍然没有实现大规模工业化生产,因为在启动和运行中仍存在一些问题,本文提出了一些解决策略和建议,以期对今后的研究有一定的指导意义.     

生物酸化乳酸菌发酵工艺的初步研究

pH值是酶反应的重要条件，由于水质的原因，啤酒麦芽中各种酶的最适pH一般都比糖化醪的pH低，所以需要用各种酸调节醪液的pH。     

影响暗发酵制氢因素的研究进展

暗发酵制氢具有产氢能力高、速率快、持续稳定、原料来源广泛且成本低等特点,易于实现规模化生产,已成为制氢领域的研究热点。文中主要介绍了对暗发酵制氢高效、持续和稳定产氢有重要影响的影响因子,如接种物、pH值、温度以及水力停留时间(hydraulic retention time,HRT)。概述了暗发酵制氢技术近年来的研究现状和其发展趋势。     

电化学生物传感器测定牛乳中乳糖含量的条件研究

将牛乳中特征物质乳糖浓度的变化引起的电化学性质用电信号表征出来,探索了电化学生物传感器测定牛乳中乳糖含量的条件,得出实验条件如下:选定突变电压为1.2V,电流测定的最佳条件是:反应温度为45℃,酶固定量为0.4μL,pH值为6.5,线性回归方程为Y=15.153X+1.5131,相关系数R2=0.9925,曲线的相关性很好;方法学考察说明,精密度为1.134%,重复性为2.624%,加标回收率为100.258%,该方法的稳定性、重复性好。     

以红糖为底物的EGSB反应器发酵制氢的研究

采用红糖废水为启动和连续运行阶段的底物,使用EGSB反应器进行连续发酵生物制氢,通过控制OLR使系统形成了稳定的乙醇型发酵。在容积负荷为97．2kgCOD／m^3·d条件下,水力停留时间为2h,得到最大5．73L／L·d的氢气产率和氢气含量平均为41．27％。     

生物制氢的发展现状

概述了氢气的重要性，对生物制氢的方式、产氢机理、影响因素以及如何筛选构建高效产氢菌株进行了综述，并提出目前生物制氢存在的问题。     

微波辐射预处理菌源对生物暗发酵制氢的影响

以牛粪堆肥为天然菌源、葡萄糖为发酵底物,考查微波辐射预处理菌源对生物暗发酵制氢的影响,并采用Illumina NovaSeq高通量测序技术分析微波辐射预处理前后菌源中细菌和古生菌的群落结构变化,揭示预处理引起的菌源微生物群落结构变化对暗发酵制氢的影响机制。结果表明,与对照组相比,微波辐射预处理后菌源的累积产H₂量和丁酸含量分别提高了27.9%和24.1%,菌源中微生物多样性下降,主要产氢微生物芽孢杆菌的相对丰度增加,产甲烷耗氢菌的相对丰度减小;产氢微生物的富集及耗氢菌活性的抑制可有效提高暗发酵制氢系统的产H₂量。     

废蜜的化学组成与生物制氢

利用甜菜制糖废蜜、废水作为底物进行连续流生物制氢，既可回收废物又能生产能源。着重阐述了甜菜废蜜中的主要成分及其在生物制氢反应中对微生物的作用。     

Effects of partial replacement of corn grain with lactose in calf starters on ruminal fermentation and growth performance

The objective of this study was to evaluate effects of partial replacement of dry ground corn with lactose in calf starters on dry matter intake, growth rate, ruminal pH, and volatile fatty acid profile. Sixty Holstein bull calves were raised on a high plane of nutrition program until 55 d of age. Calves were fed texturized calf starters containing 30.1% steam-flaked grains and lactose at 0 (control), 5, or 10% (n = 20 for each treatment) on a dry matter basis. All calves were fed treatment calf starters ad libitum from d 7 and kleingrass hay from d 35. Ruminal pH was measured continuously immediately after weaning (d 55–62) for 15 calves (n = 5 per treatment), and 3 wk after weaning (d 77 to 80) for the other 45 calves (n = 15 per treatment). Dry matter intake, growth performance, and ruminal pH variables were not affected by treatment. However, according to Spearman's correlation coefficient (r_s) analyses, lactose intake was positively correlated with dairy minimum ruminal pH (r_s = 0.306) for the data collected from d 77 to 80. Similarly, hay intake was not affected by treatment, but positively correlated with daily mean (r_s = 0.338) and maximum ruminal pH (r_s = 0.408) and negatively correlated with duration pH <5.8 (r_s = ?0.329) and area pH <5.8 (r_s = ?0.325), indicating that the variation in hay intake among animals might have masked treatment effects on ruminal pH. Ruminal molar ratio of acetate was higher (45.2 vs. 40.6%), and that of propionate was lower in 10% lactose than control (35.3 vs. 40.2%) for ruminal fluid collected on d 80; however, molar ratio of butyrate was not affected by treatment. These results indicate that lactose inclusion in calf starters up to 10% of dry matter might not affect dry matter intake and growth performance of calves, but that greater lactose and hay intake might be associated with higher ruminal pH.     

乳糖诱导对重组大肠杆菌表达CGTase的影响

以重组环糊精葡萄糖基转移酶（CGTase）表达菌株BL21（DE3）作为研究对象,比较IPTG和乳糖诱导对重组大肠杆菌表达CGTase量的影响,确定优化诱导方式。以Geobacillus CHB1的基因组DNA为模板,采用PCR技术克隆CGTase基因;利用分子操作技术构建携带有大肠杆菌Omp A信号肽的分泌型表达质粒p EASY-E2-Omp A-CGT,重组质粒热激转化至Escherichia coli BL21中进行表达;在摇瓶发酵条件下,分别以IPTG和乳糖作为诱导剂,通过SDSPAGE分析和测定胞外酶活,确定优化诱导方式。CGTase基因在Escherichia coli BL21中实现表达,且具有一定量的重组CGTase分泌至胞外;乳糖诱导的蛋白表达量优于IPTG诱导,不易形成包涵体;乳糖最佳的诱导起始菌浓度OD600为1.4,诱导浓度、温度分别为0.5%和25℃,分批流加乳糖5次和一次性加入,重组CGTase表达量无明显差异;经初步优化,胞外酶活达19.87 U/m L。Geobacillus CHB1 CGTase基因在大肠杆菌中成功实现胞外表达,乳糖可替代IPTG诱导重组CGTase。      

苹果渣液态厌氧发酵制备生物氢气的研究

以苹果渣为原料,通过液态厌氧发酵技术制备氢气,经过单因素试验和正交试验研究苹果渣与活性污泥的比例、发酵温度、初始pH、发酵液浓度对苹果渣厌氧发酵产氢效率的影响.结果表明,苹果渣液态厌氧发酵产氢的最优条件:发酵温度为(30±2)℃、活性污泥与苹果渣比率为4∶10、初始pH值8.5、发酵液浓度0.125g/mL,该务件下,苹果渣产氢率达到19.29mL/g.TS.     

灰树花多糖深层发酵pH值及溶氧条件控制研究

对灰树花真菌发酵工艺参数pH值和溶氧进行优化研究表明,pH值及溶氧对灰树花菌体及胞内外多糖产量影响较大,优化的工艺参数为:溶氧75%,pH值为5.1(0h～96h),pH值为4.2(96h～160h),此条件下菌体、胞内外多糖产量分别提高23.02%、28.95%、25.95%,表明该优化设计工艺切实可行。     

发酵麸皮制取红曲色素的初步研究

利用黑曲霉Aspergillus niger HS-16菌株作生产菌,麸皮为原料,采用厚层通风固体发酵工艺糖化麸皮,使麸皮的还原糖含量从2.8g/100g增加到糖化后的39.0g/100g,为红曲霉M-1菌株利用麸皮制备红曲麸增加了可发酵碳源。再利用红曲霉M-1菌株为生产菌,糖化麸皮为原料,采用曲盒发酵工艺制备红曲麸,红曲麸的红曲色素色价达到了372U/g,为二级红曲米红曲色素色价的74%。     

The in vitro effect of lactose on Clostridium perfringens alpha toxin production and the implications of lactose consumption for in vivo anti-alpha toxin antibody production

Necro-hemorrhagic enteritis in calves, caused by Clostridium perfringens type A, is a fatal disease, mostly affecting calves in intensive rearing systems. The lack of development of active immunity against α toxin, an essential virulence factor in the pathogenesis, has been proposed as a main trigger. In this experimental study, the effect of a set of milk replacer components on α toxin production, and the effect of lactose on in vivo antibody production, were investigated. For the latter, Holstein-Friesian bull calves (n = 18) were fed an all liquid diet that contained either a milk replacer with high-lactose content (45% DM) or the same milk replacer that was lactase treated, resulting in a lactose-free equivalent. Antibody levels against α toxin were monitored from 2 to 12 wk of age. In the in vitro part of the study, a concentration-dependent inhibitory effect of lactose on in vitro C. perfringens α toxin activity was observed, whereas protein did not influence α toxin activity. The in vivo experiment then showed from the age of 10 wk onwards, that anti-α toxin antibody levels of high-lactose animals declined, whereas antibody levels of the animals consuming lactose-free milk replacer remained the same throughout the trial. This points to a natural decline in maternal immunity of lactose-consuming animals, that is not compensated by the development of an active immunity, resulting in inferior protection. This study suggests that dietary lactose reduces C. perfringens α toxin production in vivo, which may lead to a decreased antigen presentation and thus lower serum antibody levels against the toxin. Consequently, any event causing massive α toxin production puts lactose-consuming calves at higher risk of developing necro-hemorrhagic enteritis.     

苹果渣固态厌氧发酵制备生物质氢气的研究

以苹果渣为对象,进行固态厌氧发酵制备氢气的技术研究。考察了产氢菌的富集方式、苹果渣预处理条件、厌氧发酵条件对苹果渣产氢效果的影响。研究结果表明,产氢菌的最佳富集方法为:活性污泥在室温(25℃)和pH11.0条件下预处理1.5h,然后调整pH为7.0。苹果渣粉碎至2000μm,在浓度为1%的NaOH溶液中浸泡2h后,调整pH至中性;苹果渣(w):麸皮(w):水(w)=4:1:25,在此条件下,苹果渣最大产氢量为16.47mL/gTS(TS:totalsolid)。表明苹果渣在固态条件下具有发酵生物质气体的潜力。     

分段调控pH值对阴沟肠杆菌 WL1318发酵棉秆水解糖液产氢的影响

为有效调控阴沟肠杆菌（Enterobacter cloacae）WL1318发酵棉秆水解糖液产氢的过程,研究了分段调控pH值对该菌株发酵棉秆水解糖液产氢过程中发酵液pH值、生物氢合成、棉秆水解糖液中葡萄糖和木糖利用、菌株生长的影响。结果表明,分段调控pH值避免了发酵液pH值的急剧下降。分段调控pH值处理的产氢潜力P均高于未调控处理的,48 h时调控pH值能使发酵72 h的日均产氢量较未调控处理的提高约1.5倍;24 h调控pH值和48 h调控pH值处理的累积产氢量相较未调控处理的分别提高约15%和30%。分段调控pH值对阴沟肠杆菌WL1318发酵棉秆水解糖液产氢过程中的菌体生长有较大影响,使其在调控时间点后达到活菌数峰值,且菌体生长OD600 nm值在调控时间点后均高于未调控处理的。     

Effect of inoculum conditioning on hydrogen fermentation and pH effect on bacterial community relevant to hydrogen production

The effect of conditioning for a variety of inoculums on fermentative hydrogen production was investigated. In addition, the effects of pH condition on hydrogen fermentation and bacterial community were investigated. The effect of conditioning on hydrogen production was different depending on the inoculum types. An appreciable hydrogen production was shown with anaerobic digested sludge and lake sediment without conditioning, however, no hydrogen was produced when refuse compost and kiwi grove soil were used as inoculums without conditioning. The highest hydrogen production was obtained with heat-conditioned anaerobic digested sludge, almost the same production was also obtained with unconditioned digested sludge. The pH condition considerably affected hydrogen fermentation, hydrogen gas was efficiently produced with unconditioned anaerobic sludge when the pH was controlled at 6.0 throughout the culture period and not when only the initial pH was adjusted to 6.0 and 7.0. Hydrogen production decreased when the culture pH was only adjusted at the beginning of each batch in continuous batch culture, and additionally, bacterial community varied with the change in hydrogen production. It was suggested that Clostridium and Coprothermobacter species played important role in hydrogen fermentation, and Lactobacillus species had an adverse effect on hydrogen production.