通过N-乙酰葡萄糖胺测定Sphingomonas sp.31555菌体量方法探讨

建立了一种新的方法测定威兰胶发酵液中的生物量,对该新方法进行初步条件优化以及干扰因子的排除,研究氨糖与菌体量的相关性。结果表明:随着发酵时间的增长,产胶量也会上升,而本方法应用于威兰胶发酵液中的生物量,并不受威兰胶及威兰胶水解产物的干扰影响。     

利用中温蒸煮工艺进行高浓度酒精发酵

用中温蒸煮工艺生产高浓度酒精,首先利用耐高温α－淀粉酶在9s～97℃下同时糊化和液化淀粉．接着在60℃下加高转化率的糖化酶进行糖化,最后在30℃下加酵母菌悬液进行发酵。酵母菌w4在60h内可以产生18．3％的乙醇,在成熟发酵醪中的残还原糖和总糖分别为1.2％和4．1％,细胞存活率为68．5％。如果在发酵培养基中添加一定量的硫酸铵,可进一步改进这一工艺,使成熟发酵醪的乙醇浓度提高到18.9%,发酵周期缩短到50h,残还原糖和总糖分别减少到0.27％和3.1％。     

乙醇-黄原胶耦联两步发酵

初步探索乙醇-黄原胶耦联两步发酵的可行性和生产工艺,即控制乙醇发酵,发酵液去除固形物后蒸馏回收酒精,然后利用酒精糟液中剩余营养物质进行黄原胶发酵。摇瓶和小罐试验证实方案是可行的,耦联发酵工艺优化条件:选择木薯淀粉进行乙醇发酵60 h后的酒精糟液,添加2 g/L KH2PO4,不添加无机N源。在优化条件下,7 L发酵罐中耦联发酵的黄原胶产量达到20 g/L,转化率约为50%。     

高粘发酵体系不同搅拌桨的CFD模拟及发酵验证

搅拌桨是高好氧高黏度微生物发酵实现高效反应必不可少的因素之一,不同搅拌桨组合对发酵过程的影响十分重要。威兰胶是由产碱杆菌在高耗氧高粘度发酵体系下合成的胞外微生物多糖,广泛应用于水泥、石油、油墨、食品等行业中。本研究借助于计算流体力学(Computational fluid dynamics,CFD)的方法,以威兰胶发酵液体系为研究体系,研究了6种不同搅拌桨组合在反应器内流体速率分布、剪切速率、和气含率等参数。将模拟效果较好的3种组合用于威兰胶发酵过程。研究表明MB-4-6搅拌桨组合对改善发酵罐内部的溶氧及流场分布效果最明显,威兰胶产量水平提高了13%。同时在该组合下威兰胶的产品粘度得到有效提高。     

XCCNAU—92发酵生产黄原胶的适宜条件

XCCNA－92发酵生产黄原胶的适宜条件是：好氧,发酵温度为30℃,培养基起始pH为7.0,接种量6％,发酵周期60h。利用最佳培养基配方,在30℃,150r／min条件下发酵72h,工业级黄原胶产量达40.84g／L,发酵液粘度86000cp,丙酮含量4．1％,碳源转化率达68.1％。     

代谢改造热带假丝酵母发酵木糖母液生产木糖醇

木糖醇是一种在食品、医药、轻工等领域具有广泛用途的多元醇,目前主要通过酸水解木聚糖获得木糖并进一步化学催化加氢方法制备。提取木糖过程中会产生大量的木糖母液副产物,其中含有一定浓度的葡萄糖、木糖、阿拉伯糖等碳源,以及少量的糠醛、四氢呋喃等物质。研究微生物转化木糖母液生产高附加值化学品不仅能够提高木糖母液的利用价值,而且能够减少环境污染。热带假丝酵母不仅能够利用葡萄糖,也具有高效的木糖代谢途径。首先利用代谢工程技术删除了热带假丝酵母菌株的木糖醇脱氢酶基因,获得能够转化木糖积累木糖醇的突变株。在此基础上,评价了突变株在木糖母液培养基中的发酵性能。通过单因素优化实验确定了突变株发酵生产木糖醇较优的发酵工艺:培养基组成为木糖母液300g/L,玉米浆5g/L;最佳发酵条件为:发酵温度35℃,初始p H为5.0,接种量15%,200r/min摇床培养140h。利用优化后的发酵工艺,木糖醇产量达到83.01g/L。初步建立了转化木糖母液生产木糖醇的工艺,为进一步利用木糖母液奠定了基础。     

粗糙脉孢菌(Neurospora crassa)木糖发酵的研究

研究了不同通氧条件和培养基初始pH等对粗糙脉孢菌(Neurospora crassa)AS3．1602木糖发酵的影响。结果表明,粗糙脉孢菌具有较强的发酵木糖产生乙醇及木糖醇的能力。通气量对木糖发酵有较大的影响。乙醇发酵适合在半好氧条件下进行,此时乙醇的转化率达到63．2％。木糖醇发酵适合在微好氧的条件下进行,转化率达到31．8％。木糖醇是在培养基中乙醇达到一定浓度后才开始积累。培养基的初始pH对木糖发酵产物有较大的影响,乙醇产生最适pH5．0,木糖醇产生最适pH4．0。在培养基pH为碱性条件时,木糖发酵受到很大的抑制。初始木糖浓度对产物乙醇及木糖醇的产率有很大的影响。葡萄糖的存在会抑制木糖的利用,对乙醇和木糖醇的产生也有很大的影响。     

肌苷产生菌枯草芽孢杆菌Bs菌株的选育和发酵条件

1．用枯草芽孢杆菌(Bacillus subtilis)腺嘌呤营养缺陷型(ade-)No 18经1次亚硝基胍(MNNG)。诱变处理及2次单菌落分离,获得了能利用酶法制造葡萄糖3次结晶母液,发酵生产肌苷的变异菌株B,。在适宜条件下,摇瓶肌苷产量在7.0克／升以上。 2．不同来源的酵母粉及其在培养基中的含量,对肌苷产量均有显著影响。在所试验的酵母粉中,以北京光华木材厂生产的圆酵母最好,在种子和发酵培养基中的逢合用量分别为1.0一1.4％和1.2一1.4％。 3．在发酵过程中,次黄嘌呤的积聚和肌苷积聚有着明显的消长关系。4．枯草芽孢杆菌B4菌株具有很强的分段合成肌苷的能力,当添加0．3％次黄嘌呤时,可获得高于对照93．3％的肌苷产量,但转化率以添加0．1％次黄嘌呤时为最高。     

酿酒酵母和克鲁维酵母发酵菊芋生产燃料乙醇

为获得菌株发酵菊芋生产燃料乙醇的最佳方案,首先选取实验室保存的重组菌株R32对其产酶条件进行优化,其最高产菊粉酶活性为298.8 U· mL-1,此时的最佳培养基配方为:YPG培养基为酵母粉1％ (w/v),蛋白胨2％ (w/v),甘油0.5％ (v/v);YPM培养基为酵母粉1％ (w/v),蛋白胨2％ (w/v),甲醇1％(v/v);培养基pH为自然初始pH.然后选取酿酒酵母S.c和克鲁维酵母Klu,比较是否在添加重组菌株R32粗酶液条件下,两株酵母菌分别进行单独发酵和混合发酵时的产乙醇能力,以获得最佳的发酵组合.结果表明,酿酒酵母S.c和克鲁维酵母Klu在未添加重组菌株R32粗酶液时,混合一步发酵获得的乙醇含量较高,发酵84 h时乙醇含量为11.37％.添加重组菌株R32粗酶液进行两步发酵时,2株酵母菌混合发酵72 h时,乙醇含量为11.43％.2种发酵组合的最高乙醇含量以及各个发酵参数基本相同,虽然一步法发酵时间延长,但节省成本,操作简单,更适宜工业生产应用.最后对其进行正交试验优化,培养条件为菊粉浓度225 g· L-1,脲素浓度40 g·L-1,接种量15％,pH为5时,酿酒酵母菌S.c和克鲁维酵母Klu混合一步发酵法的最高乙醇体积比达11.82％.     

分枝杆菌Mycobacterium ZLP生产雄烯二酮（4-AD）的优化工艺

利用正交实验对分枝杆菌降解植物甾醇生产雄烯二酮（4-AD）的发酵培养基进行优化,同时进行温度和pH的优化。结果表明：培养基的最佳组成为质量分数2．0％葡萄糖、2．0％蛋白胨、0．7％MgSO4、0．8％K2HPO4;最适温度28℃、最适pH7．0,在此基础上发酵96h,4-AD的产率可达到62．15％。     

Distillery and curd whey wastes as viable alternative sources for biosurfactant production

Biosurfactant production from synthetic medium and industrial waste, viz. distillery and whey wastes was investigated by using an oily sludge isolate Pseudomonas aeruginosa strain BS2. In synthetic medium separately supplemented with glucose and hexadecane as water-soluble and -insoluble carbon sources, respectively, strain BS2 reduced the surface tension of the fermentation broth from 57 to 27 mN/m. The culture produced biosurfactant during the stationary growth phase and its yield was 0.97 g/l. The culture utilized distillery and whey wastes for its growth, as maximum cell counts reached to 54 × 10⁸ and 64 × 10⁹ c.f.u./ml from an initial inoculum size of 1 × 0⁵ c.f.u./ml, respectively, within 48 h of incubation and in these wastes the yields of biosurfactant obtained were 0.91 and 0.92 g/l, respectively. In synthetic medium, distillery and whey wastes, strain BS2 produced a crystalline biosurfactant which belonged to the category of secondary metabolites and its maximum production occurred after the onset of nitrogen-limiting conditions. After recovering biosurfactant from the fermented waste, the chemical oxygen demand (COD) of distillery and whey wastes was significantly reduced by 81 and 87%, respectively. Total acids, nitrogen and phosphate levels in distillery waste were reduced by 90, 92 and 92%, respectively, while in case of whey waste the concentration of these nutrients was reduced by 88, 95 and 93%, respectively. The isolated biosurfactant possessed potent surface active properties, as it effectively reduced the surface tension of water from 72 to 27 mN/m and formed 100% stable emulsions of a variety of water-insoluble compounds such as hydrocarbons, viz. hexadecane, crude oil, kerosene and oily sludge and pesticides, viz. dichlorodiphenyltrichloroethane (DDT) and benzene hexachloride (BHC). The effectiveness of biosurfactant was also evident from its low critical micellar concentration (CMC) which was 0.028 mg/ml.     

产油真菌在甘薯淀粉废水中发酵的初步研究

目的:利用甘薯淀粉废水发酵低成本获取微生物油脂。方法:以甘薯淀粉废水为发酵基质,进行菌株筛选、发酵工艺优化及油脂成分的气相色谱分析。结果:筛选出一株刺孢小克银汉霉F7,生物量为19.375g/L,含油量为45.1%。菌株F7发酵第11天生物量达到18.140g/L,含油量达到51.2%,COD去除率87%。研究发现与对照相比,NaAc和KH2PO4对生长、产油以及出水COD去除有显著促进作用,NaAc2g/L时生物量提高了25.4%,含油量提高了4.4%,COD下降了52.0%,KH2PO4的作用稍次之。结论:资源化利用甘薯淀粉废水发酵生产微生物油脂同时降低废水COD是一条可行的途径,可以为生物柴油提供廉价油源。     

Characterization of technological features of dry yeast (strain I-7-43) preparation, product of electrofusion between Saccharomyces cerevisiae and Saccharomyces diastaticus, in industrial application

The aim of the study was to verify the technological usability and stability of biotechnological features of active dry distillery yeast preparation (strain I-7-43 with amylolytic abilities) applied to full-scale production of agricultural distillery. Various reduced doses of glucoamylase preparation (San-Extra L) were used for starch saccharification, from 90% to 70% in relation to the full standard dose of preparation. The dry distillery yeast I-7-43 were assessed positively in respect to fermentation activity and yield of ethanol production. Application of the dry yeast I-7-43 preparation in distillery practice lowers the costs of spirit production by saving the glucoamylase preparation (up to 30%) used in the process of mash saccharification. Concentrations of the volatile fermentation by-products in raw spirits obtained from fermentations with application of I-7-43 strain were on the levels guaranteeing good organoleptic properties of distillates.     

甘蔗糖蜜酒精废液混菌发酵菌体蛋白的研究

本文报导利用甘蔗糖蜜酒精废液混菌发酵高质量菌体蛋白的研究,通过热带假丝酵母Ｃａｎｄｉｄａ ｔｒｏｐｉｃａｌｉｓ种合融合株Ｃｔ－３配伍其他菌株,混菌发酵时间缩短２￣４ｈ,生物量可达２０ｇ／Ｌ,粗蛋白质含量５０￣５３％,灰份≤１０％,水分为５￣８％,与Ｃｔ－３单菌发酵相比,蛋白质提高４￣６％。     

Isolation of thermotolerant ethanologenic yeasts and use of selected strains in industrial scale fermentation in an Egyptian distillery

An enrichment and isolation program for new ethanol-producing thermotolerant yeasts as well as a screening program of some known thermotolerant strains resulted in the selection of several strains capable of growth at 40-43 degrees C. Among these strains four grew and fermented sugar cane molasses at 43 degrees C under batch conditions with sugar-conversion efficiencies >94% and ethanol concentrations 6.8-8.0% (w/v). The two best-performing strains, a Saccharomyces cerevisiae F111 and a Kluyveromyces marxianus WR12 were used in eight 87.5 m(3) fermentation runs (four using each strain) for industrial ethanol production in an Egyptian distillery using sugar cane molasses. Mean ethanol production was 7.7% and 7.4% (w/v), respectively, with an added advantage of cooling elimination during fermentation and higher ethanol yields compared to the distillery's S. cerevisiae SIIC (ATCC 24855) strain in use. The isolate S. cerevisiae F111 was subsequently adopted by the distillery for regular production with significant economical gains and water conservation.     

Production of lactic acid and fungal biomass by Rhizopus fungi from food processing waste streams

This study proposed a novel waste utilization bioprocess for production of lactic acid and fungal biomass from waste streams by fungal species of Rhizopus arrhizus 36017 and R. oryzae 2062. The lactic acid and fungal biomass were produced in a single-stage simultaneous saccharification and fermentation process using potato, corn, wheat and pineapple waste streams as production media. R. arrhizus 36017 gave a high lactic acid yield up to 0.94-0.97 g/g of starch or sugars associated with 4-5 g/l of fungal biomass produced, while 17-19 g/l fungal biomass with a lactic acid yield of 0.65-0.76 g/g was produced by the R. oryzae 2062 in 36-48 h fermentation. Supplementation of 2 g/l of ammonium sulfate, yeast extract and peptone stimulated an increase in 8-15% lactic acid yield and 10-20% fungal biomass.     

Phenolic composition and radical scavenging activity of sweetpotato-derived shochu distillery by-products treated with koji

Phenolic composition and radical scavenging activity in the shochu distillery by-products of sweetpotato (Ipomoea batatas L.) treated with koji (Aspergillus awamori mut.) and cellulase (Cellulosin T2) were investigated to develop new uses. Koji and Cellulosin T2 treatment of shochu distillery by-products from sweetpotatoes, rice, and barley increased phenolic content. Caffeic acid was identified as a dominant phenolic component in the shochu distillery by-products of the sweetpotato. Adding koji and/or Cellulosin T2 to the shochu distillery by-product indicated that koji was involved in caffeic acid production. Caffeic acid was not detected in raw or steamed roots of "Koganesengan", the material of sweetpotato for shochu production, suggesting that it is produced during shochu fermentation. The phenolic content and radical scavenging activity the shochu distillery by-product treated with koji and Cellulosin T2 were superior to those of commercial vinegar. These results suggest that koji treatment of sweetpotato-derived shochu distillery by-products has potential for food materials with physiological functions. Further koji treatment of sweetpotato shochu-distillery by-products may be applicable to mass production of caffeic acid.     

Potential utilization of guar gum industrial waste in vermicompost production

Recycling of guar gum industrial waste through vermitechnology was studied under laboratory conditions by using composting earthworm Perionyx excavatus (Perrier). Three different combination of guar gum industrial waste namely guar gum industrial waste:cow dung:saw dust in 40:30:30 ratio (T1), guar gum industrial waste:cow dung:saw dust in 60:20:20 ratio (T2), and guar gum industrial waste:cow dung:saw dust in 75:15:10 ratio (T3) were used for vermicomposting experiments. Chemical changes during vermicomposting were measured and comparatively T2 showed great increase (from its initial level) for total N (25.4%), phosphorus (72.8%) and potassium (20.9%) than the other treatments. T2 also showed higher vermicomposting coefficient (VC), higher mean biomass for P. excavatus (146.68 mg) and higher cocoon production (about 21.9% and 645.5% more than the T1 and T3, respectively). Maximum earthworm mortality during vermicomposting was recorded with T3 treatment while zero mortality was recorded for T2 treatment after 150 days. Overall, T2 treatment appeared to be an ideal combination for enhancing maximum biopotential of earthworms to management guar gum industrial waste as well as for earthworm biomass and cocoon production.