糠醛渣直接同步糖化发酵生产乙醇过程比较研究

以糠醛渣为原料,直接同步糖化发酵(SSF)生产乙醇,并与水洗糠醛渣生产乙醇进行对比。通过考察不同条件来优化同步糖化发酵生产工艺条件,并分析表征了SSF过程中乙醇浓度和副产物浓度变化。优化条件为:糠醛渣底物质量分数10%,纤维素酶用量12%,无患子皂素质量浓度0.5g/L,酵母接种量7g/L,同步糖化发酵乙醇得率达到其理论得率的93.1%。与水洗糠醛渣相比,糠醛渣直接SSF过程可将原料吸附的5.50%葡萄糖部分转化为乙醇。水洗糠醛渣SSF生产乙醇所产生的副产物要远低于糠醛渣直接生产所产生的副产物,添加无患子皂素可有效抑制糠醛渣同步糖化发酵过程中副产物的产生。     

菊芋秸秆的稀酸水解及乙醇发酵

菊芋作为一种非粮作物,块茎和秸秆均可以被微生物发酵生成乙醇。采用稀酸法对菊芋秸秆进行预处理,通过单因素实验,考察了预处理温度、预处理时间、稀酸浓度、料液比4个因素,得到的优化结果:料液比为1∶8,酸解温度为121℃,酸质量分数为1.5%,酸解时间为1 h。此条件下水解菊芋秸秆,还原糖得率高达53.7%;预处理后的水解液在添加纤维素酶和木聚糖酶后,考察Kluyveromyces marxianus 1727的乙醇发酵能力,其同步糖化发酵与分步糖化发酵乙醇产量分别为25.91 g/L和25.63 g/L,生产效率分别是0.54 g/L/h和0.26 g/L/h。结果表明,稀酸水解的菊芋秸秆可用作底物生产燃料乙醇。     

蒸汽爆破麦草同步糖化发酵转化乙醇的研究

近年来对木质生物资源同步糖化发酵转化乙醇的研究较多,但是,麦草同步糖化发酵转化乙醇的最佳工艺条件还未确定。文中采用正交试验设计的方法,对在混合酶(纤维素酶Celluclast 1.5 1,β-葡萄糖苷酶Novozym 188)与酿酒酵母菌作用下,稀硫酸催化的蒸汽爆破麦草原料同步糖化发酵转化乙醇的工艺条件进行研究,详细讨论了反应温度、底物质量浓度、发酵液pH值、纤维素酶浓度对乙醇质量浓度和得率的影响。结果表明,工艺条件对乙醇质量浓度和得率的影响程度由高到低依次为:底物质量浓度、纤维素酶浓度、发酵液pH值、反应温度。最佳工艺条件为反应温度35℃,底物质量浓度100 g/L,发酵液pH值5.0,纤维素酶浓度30 FPU/g。在此条件下,随着反应时间的延长,乙醇质量浓度持续上升。反应72 h后,乙醇质量浓度和得率分别达到22.7 g/L和65.8%。     

β-葡萄糖苷酶高温同步糖化发酵产乙醇应用研究

利用Trichoderma sp.W2所产的嗜温耐乙醇β-葡萄糖苷酶及耐高温酵母Kluyveromyces marxianus NCYC 587,以气爆秸秆为原料进行高温同步糖化发酵。研究结果表明:在42℃条件下,接种体积分数10%,底物质量分数15%,发酵pH值为4.8,β-葡萄糖苷酶添加量为30 U/g底物条件下发酵效果最好。NCYC 587能迅速利用预水解产生的葡萄糖发酵并积累乙醇,同时能利用部分木糖,但在发酵后期,葡萄糖利用完全后会代谢利用一定量的乙醇,致使发酵过程中乙醇质量浓度始终维持在一个相对较低的水平。乙醇最高质量浓度达到20.56 g/L,乙醇产率达80.64%。添加嗜温耐乙醇β-葡萄糖苷酶于高温同步糖化发酵能有效解决纤维素酶解发酵过程终端产物抑制的难题。     

糠醛渣纤维乙醇同步糖化发酵过程研究

以过碱化处理的糠醛渣为原料,采用正交试验法进行同步糖化发酵(SSF)转化乙醇工艺条件及过程研究.通过考察反应温度、pH、纤维素酶用量和表面活性剂浓度来优化同步糖化发酵转化工艺条件.在正交优化条件基础上,进行了5 L发酵罐试验,并同步分析表征了发酵过程中还原糖浓度、乙醇浓度、酵母细胞数、纤维素含量及其结构变化.同步糖化发酵转化糠醛渣生成乙醇的优化条件为:反应温度38℃,pH 4.2,纤维素酶用量20 FPU/(g纤维素),吐温-20质量分数0.15%,酵母接种量10%.发酵罐中同步糖化发酵糠醛渣生成乙醇的转化率达到72.33%,过程分析表明反应时间为27 h时,糠醛渣糖化发酵产乙醇的转化率达到最高,比其他纤维原料的反应转化时间大大缩短.同步糖化发酵过程中,糠醛渣纤维素含量逐步降低,纤维索表观结晶度呈下降趋势,纤维素微晶尺寸减小.     

木薯酒精渣同步糖化发酵制乙醇的工艺研究

研究了利用木薯酒精厂废渣为原料发酵生产乙醇的方法,结果表明:经过简单的机械粉碎后,通过同步糖化发酵生产乙醇是可行的。发酵条件为:木薯酒精渣经粉碎后取粒径小于0.85mm的部分,初始料水比1∶8,纤维素酶添加量为每克木薯渣(干重)30FPU,发酵过程中在24h内分批将剩余木薯渣加入至总料水比达到1∶2.5,利用5L发酵罐进行同步糖化发酵,发酵液中乙醇质量浓度达到52g/L,木薯酒精渣到乙醇的收率达到13%。纤维素酶的添加量对发酵效果影响显著,当达到每克木薯渣(干重)50FPU时,发酵液中乙醇质量浓度可达65g/L,乙醇收率达到16%。     

脱木素对糠醛渣同步糖化发酵乙醇转化的影响

对碱性过氧化氢处理后的糠醛渣样品进行同步糖化发酵转化乙醇研究。结果表明,木素脱除提高糠醛渣转化乙醇得率。与未处理糠醛渣相比,脱木素糠醛渣样品发酵96h后水解液中乙醇浓度由6.8g/L提高至14.5g/L,乙醇转化率由50.6%提高至69.35%。     

稀酸浸渍气爆预处理对纤维素乙醇同步糖化发酵的影响

纤维素乙醇预处理过程效率偏低是影响纤维素乙醇发展的一个重要因素。通过改进传统蒸汽爆破预处理方法,在蒸汽爆破前加入稀酸浸渍,有效地提高了后续同步糖化发酵的水平。采用硫酸浸渍气爆预处理后的草浆同步糖化发酵乙醇质量浓度达到27.5 g/L,达到葡萄糖乙醇理论产率的81%;采用乙酸浸渍气爆预处理后的草浆同步糖化发酵乙醇质量浓度达到25.5 g/L,达到葡萄糖乙醇理论产率的77%;相比传统气爆草浆用于同步糖化发酵,稀酸预处理能有效地减少抑制物的生成,提高后续直接利用草浆进行同步糖化发酵的水平,从而提高生产效率,降低生产成本,是可应用于工业化纤维素乙醇生产的重要方法。     

玉米原料同步糖化发酵乙醇工艺

以液化醪为研究对象,对影响同步糖化发酵的植酸酶、酸性蛋白酶、糖化酶、酵母和酵母促进剂的添加量进行Placket-Burman(PB)设计,确定酸性蛋白酶、糖化酶和酵母是影响同步糖化发酵效果的显著性因素。利用响应面实验优化的同步糖化发酵工艺条件为液化醪w(固)=28%,发酵温度32℃,添加量分别为糖化酶95～145 u/g,酸性蛋白酶14～30 μL/L,酵母0.017～0.033 g/L,发酵周期48～72 h,ρ(乙醇)=107 g/L,发酵成熟醪ρ(葡萄糖)0.7 g/L。     

与膜耦合的细胞固定化串联发酵制乙醇的研究

利用植物纤维作为廉价的糖源生产燃料乙醇是解决世界能源危机的最有效途径.今研究采用海藻酸钙固定普通酿酒酵母细胞和嗜鞣管囊酵母细胞于两个串联的发酵罐内,连续发酵葡萄糖和木糖组成的糖液并与膜耦合来制取酒精.通过硅橡胶膜(PDMS)的渗透蒸发过程,将产品乙醇从发酵液中移出,减少了产物乙醇对发酵的抑制作用.实验结果表明,这套采用海藻酸钙固定酵母细胞进行连续发酵并与膜耦合的生物反应器系统,在稀释率为0.321 h-1下稳定运行,剩余葡萄糖和木糖浓度分别为0.134、4.921 g·L-1,乙醇得率为O.457 g(乙醇)·g-1(糖),是理论得率的92.64%.生产能力达到10.996 g·L-1·h-1.与其它发酵方式相比较,用海藻酸钙来固定细胞并与膜耦合的发酵过程可增大酵母细胞浓度,明显降低乙醇对酵母的抑制作用,并提高糖的转化率.     

A continuous alcohol fermentation byKluyveromyces fragilis using jerusalem artichoke

In this study, a continuous fermentation of inulin in the tubers of Jerusalem artichoke (JA) for alcohol production was investigated. Experiments were also conducted on the fermentation of mashed JA tubers, without extracting the juice. In a continuous fermentation of the juice of JA tubers, alcohol productivity was increased by 3.8 times as compared with that obtained in a batch fermentation. The liquefaction of mashed JA tubers by enzymes, pectinase and cellulase followed by fermentation of liquefied solution byK. fragilis was found as effective as direct fermentation of the juice. The results of this study are expected to provide valuable information in the utilization of Jarusalem artichoke for ethanol production.     

Pure fructose syrup and ethanol production from high fructose corn syrup supplemented with Jerusalem artichoke juice

Saccharomyces cerevisiae ATCC 36859 preferentially consumes glucose from glucose–fructose mixtures. Synthetic media and complex media containing high fructose corn syrup supplemented with Jerusalem artichoke juice were used for the production of pure fructose syrup by the conversion of glucose to ethanol. Fructose was not converted in these processes. Increasing the concentration of Jerusalem artichoke juice increased the yields of ethanol and biomass and decreased the process time. A similar effect was obtained at a low juice concentration when a larger amount of biomass was used for the inoculum. The product from this process contained only fructose and ethanol. Use of food-grade materials results in a pure fructose syrup that is suitable for human consumption.     

Klebsiella pneumoniae发酵菊芋生产2,3-丁二醇的初步研究

对Klebsiella pneumoniae发酵菊芋块茎生产2,3-丁二醇进行了初步研究,通过摇瓶实验考察了不同碳源及培养基中微量元素对发酵的影响. 结果表明,菊芋是良好的发酵2,3-丁二醇的底物,以其为底物时产物浓度和生产强度比葡萄糖发酵提高了42%以上,培养基中不添加微量元素对菊芋发酵基本没有影响,因而可简化培养基成分以降低生产成本. 在发酵罐批式流加实验中,发酵56 h菊芋发酵的产物浓度和生产强度分别为81.47 g/L和1.45 g/(L×h),与葡萄糖发酵结果相当.     

能源植物菊芋制备生物基化合物研究进展

生物质作为工业填料在制备化学品的过程中具有可再生性、碳元素利用平衡等优点，但大部分能源植物存在来源于粮食必需品、与农作物争夺优质土地的问题。天然生物质菊芋因具有优良的生长特性、糖类组分含量高、单体官能团多样等特点，被认为是未来最重要的非粮能源植物之一。本文介绍了通过物理过程、生物过程及化学过程等不同途径高附加值化菊芋的研究进展，总结不同方式制备生物基化合物的特点。基于菊芋主要因其根茎中含有丰富的不易被人体消化的菊糖、果糖基多糖聚合度低、组成多糖和还原糖的碳源单体高度单一等优点，着重介绍目前菊芋根茎作为底物制备生物基化合物的过程，分析了通过化学催化法或发酵法制备多元醇、5-羟甲基糠醛、乳酸酯等产品的反应条件、催化剂或生物酶的类型等。基于菊芋秸秆中富含纤维素、半纤维素和木质素等木质纤维素的优势，简述了以纤维素和半纤维素类碳水化合物和木质素的主要研究现状，以及对菊芋秸秆直接催化转化的效果，突出菊芋秸秆转化的优势，提出菊芋秸秆作为底物高效制备目标产物的改进措施。对菊芋根茎和菊芋秸秆的高附加值化过程和效果的分析表明，加强对非粮能源植物菊芋的深加工与生物、化学转化技术的研究，配合生物法与化学法相结合的手段，能加快菊芋工业化应用取得实质性的进展。     

Biodiesel production from Jerusalem artichoke (Helianthus Tuberosus L.) tuber by heterotrophic microalgae Chlorella protothecoides

BACKGROUND: As a potential source of biomass, Jerusalem artichoke has been studied for bioethanol production; however, thus far it has not been investigated for the production of other liquid biofuels, such as biodiesel. This work aims to develop a novel approach for biodiesel production from Jerusalem artichoke tuber using heterotrophic microalgae. RESULTS: In this study, Chlorella protothecoides utilized hydrolysate of Jerusalem artichoke tuber as carbon source and accumulated lipid in vivo, with lipid content as high as 44% by dry mass, and a carbon source to lipid conversion ratio of about 25% in a 4‐day scale cultivation. The lipids were extracted and then converted into biodiesel by transesterification. Cetane acid methyl ester, linoleic acid methyl ester and oleic acid methyl ester were the dominating components of the biodiesel produced. Unsaturated fatty acids methyl ester constituted over 82% of the total biodiesel content. CONCLUSION: This work suggests the feasibility of an alternative method of producing biodiesel from Jerusalem artichoke tuber using microalgae cultivation, and a cost reduction of carbon source feed in algal oil production can be expected. Copyright © 2009 Society of Chemical Industry     

菊芋渣选择性吸附天然菊粉酶催化制备短链低聚果糖

以菊粉加工废弃物（菊芋渣）选择性吸附黑曲霉产的天然菊粉酶提高菊粉酶活力（I）与转化酶活力（S）的比值（即I/S比值）,并将此纯化后的菊粉酶应用于后续的短链低聚果糖（FOSs）的生产,考察了纯化后菊粉酶对FOSs产率的影响。结果显示：选择的较佳吸附条件为：菊芋渣质量浓度为100 g/L,吸附pH值为5.0,吸附温度为4℃。经菊芋渣的选择性吸附,天然菊粉酶酶系中转化酶活力降低80.84%,菊粉酶活力保留67.92%,I/S比值由原来的1.13上升至4.02。经菊芋渣选择性吸附后的天然菊粉酶用于制备短链低聚果糖,可显著提高短链低聚果糖的浓度,酶解条件为：菊粉质量浓度为40 g/L,酶解pH值为5.0,温度为50℃,酶用量为20 U/g （以菊粉质量计）,短链低聚果糖质量浓度达到16.06g/L,是原酶液制备短链低聚果糖的2.55倍;短链低聚果糖得率为40.16%。     

A study on the factors for improving the ethanol production from Jerusalem artichoke by Kluyveromyces fragilis

This study is to investigate the factors influencing the alcohol production byKluyveromyces fragilis using the juice of Jerusalem Artichoke tubers. The cell growth rate and ethanol production rate were stimulated by aeration and by the addition of unsaturated fatty acids and the cell mass production and the ethanol production were substantially improved. It was found that oxygen and unsaturated fatty acids added played a decisive role on the increase of alcohol tolerance of yeast.     

Evaluation of four crops for nitrogen utilization and carbohydrate yield

Field experiments with 5 levels of Nitrogen (0 to 200 kg/ha) and 4 crops—chicory(Chocorium intybus), fodder beet(Beta vulgaris), Jerusalem artichoke(Helianthus tuberosus) and grain sorghum(Sorghum bicolor) that have shown promise for alcohol production were conducted at 2 locations in California. Nitrogen uptake patterns, were evaluated and N cost for producing plant storage parts and fermentable carbohydrate were calculated. The crops were compared on these criteria. The yields of vegetative and storage organs during the crop growth are reported and their rate of change with growing time were determined. Yields of vegetative parts and total biomass of Jerusalem artichoke (JA) and grain sorgum (GS) were higher than to that of chicory (CH) and fodderbeet (FB). However, due to their lower harvest index, JA and GS produced lower yields of fermentable carbohydrate and at a much higher N cost than CH and FB. Fodder beet had the highest N uptake and the response to applied N was linear. Chicory and fodder beet which had lower N uptake rates continued N uptake from soil for a longer period than either grain sorghum or Jerusalem artichoke. The N uptake of the four crops were in the decreasing order of fodder beet, grain sorghum, Jerusalem artichoke, and chicory. With N application, N concentrations of vegetative as well as storage part increased in all the crops, however, a greater proportion of applied N went into vegetative parts. At both locations, CH had the lowest N cost per unit fermentable carbohydrate produced.     

基于果糖与葡萄糖不同混合比例的丙酮丁醇发酵

介绍了以不同底物的丁醇发酵结果,阐述了在以55g/L葡萄糖与果糖（1∶4）混合糖模拟菊芋物料为底物的丁醇发酵过程中存在果糖利用及丁醇产量较低等问题,研究了基于葡萄糖与果糖不同混合比例（1∶2、2∶3、3∶2及3∶1）的丁醇发酵性能。研究结果说明了随着混合比例提高,发酵时间由76h缩短至48h,菌体最大生物量OD620由2.1提高至4.3,而当葡萄糖与果糖混合比例为1∶2时,发酵过程中菌体细胞对果糖代谢能力最佳,且终点残糖浓度仅为2.1g/L,果糖利用效率达到95.03%,丁醇及总溶剂产量分别达到9.7g/L与16.0g/L。     

菊芋的种植和开发利用

本文综述了一种优良能源作物菊芋的特点、种植和开发利用。期待对菊芋的进一步开发带来社会、环境和经济效益。