一株丝孢酵母属菌株发酵产油脂的研究

通过摇瓶发酵,比较丝孢酵母属菌株JM-B在不同营养和发酵条件下的产油脂情况。以菌体生物量、油脂产量、油脂含量及油脂系数为指标,优化碳源质量浓度、氮源组成与质量浓度、磷酸盐质量浓度等发酵培养基组成,优化接种量、发酵温度、摇床转速、发酵时间等发酵条件,利用气相色谱法测定油脂脂肪酸组成。结果表明:最适培养基组成为葡萄糖100 g/L,硫酸铵1.0 g/L,酵母膏10 g/L,磷酸二氢钾4 g/L,p H自然;最适发酵条件为发酵温度25℃,摇床转速160 r/min,种子液种龄36 h,接种量10%(以发酵液体积计),发酵时间144 h。在最适培养条件下,得到的菌体生物量和油脂产量最高,分别为16.14、6.64 g/L,油脂产量较优化前提高了161.4%,油脂中饱和脂肪酸含量比优化前降低了28.1%。可以认为丝孢酵母属菌株JM-B是一株很有开发潜力的产油脂菌株。     

植物油对被孢霉菌发酵生产花生四烯酸的影响

研究了四种植物油(豆油、棕榈油、花生油、芝麻油)对被孢霉菌发酵生产花生四烯酸(Arachidonic acid, AA)的影响.结果表明:(1)四种植物油显著促进了菌体油脂的积累;(2)被孢霉生长在以植物油为唯一碳源的培养基上时,菌体油脂中的AA含量比以葡萄糖为碳源时显著下降;生长在以植物油和葡萄糖为混合碳源的培养基上时,与以葡萄糖为碳源相比油脂中的AA含量仍然下降,但比生长在以植物油为唯一碳源时AA含量有所提高.说明这四种植物油对花生四烯酸的合成有抑制作用.(3)菌体油脂成分与培养基中植物油的油脂成分有一定的相似性.     

油脂酵母CHB5产油脂发酵条件优化

以油脂酵母CHB5为实验材料,通过设计单因素试验,对各项与菌体产油脂有关的条件进行优化,确定摇瓶发酵最优产油脂条件:碳源,葡萄糖;氮源,硫酸铵;培养温度为25℃,接种量为10%,初始pH为7.0,发酵时间为96h。最后可得油脂产量为1.22g/L,油脂含量达30.5%;菌体生物量为5.93g/L。     

响应面法优化皮状丝孢酵母产油脂发酵培养基

以皮状丝孢酵母（Trichosporon cutaneum）为出发菌株,对其产油脂的发酵培养基进行研究。以油脂产量为评价指标,通过单因素试验研究发酵培养基中的碳源、氮源、外源因子对油脂产量的影响,然后利用响应面试验对培养基进行优化。结果表明,最佳培养基配方为葡萄糖97.6 g/L、玉米浆干粉4.4 g/L、乙酸钠0.09 g/L。在该优化条件下,皮状丝孢酵母的油脂产量达到了14.4 g/L。     

玉米秸秆水解液发酵产生物油脂动力学研究

对发酵性丝孢酵母在玉米秸秆水解液中发酵合成微生物油脂动力学特性进行了研究.采用Logistic菌体生长模型、Luedeking-Piret模型和产物生成的基质消耗模型,描述了完整发酵过程的动力学特性,提出了发酵过程中菌体生长、微生物油脂合成、基质消耗的动力学模型.采用牛顿迭代法对模型参数进行非线性拟合,结果表明,模型计算与试验数据能较好地拟合,菌体生长、产物油脂生成及糖分消耗等3条曲线的相关指数R2分别为0.990、0.987和0.890.表明该动力学模型可以较好描述发酵性丝孢酵母发酵过程的动力学特征.     

发酵条件对发酵性丝孢酵母脂肪酸组成的影响

通过摇瓶发酵，研究了温度、摇瓶转速、碳源种类和浓度对发酵性丝孢酵母（Trichosporom fermentans）脂肪酸组成的影响。气相色谱法分析结果表明，较高发酵温度能提高菌体油脂的脂肪酸饱和程度，此条件下饱和脂肪酸含量占脂肪酸总量的49．1％：摇瓶转速高有利于菌体油脂不饱和脂肪酸的生成；木糖浓度为100g／L时菌体油脂中饱和脂肪酸含量最高，占脂肪酸总量的50．4％；木糖比葡萄糖更容易被转化生成饱和脂肪酸含量较多的油脂。菌体脂肪酸组成包括肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸和亚油酸，其中棕榈酸和油酸含量较高。     

5株非酿酒酵母的耐受性及发酵特性研究

以陆生伊萨酵母（Issatchenkia terricola）、浅白隐球酵母（Cryptococcus albidus）、葡萄汁有孢汉逊酵母（Hanseniaspora uvarum）、美极梅奇酵母（Metschnikowia pulcherrima）、戴尔有孢圆酵母（Torulaspora delbruecki）为试材,分析了5株非酿酒酵母的生长特性、耐受性和碳源氮源同化能力及发酵速率。结果表明,戴尔有孢圆酵母的生长量较大,耐受的葡萄糖质量浓度为500 g/L、酒精体积分数为18%、SO2质量分数为420 mg/L,可同化氮源3种、碳源11种;陆生伊萨酵母的生长量较小,耐受的葡萄糖质量浓度为350 g/L、酒精体积分数为6%、SO2质量分数为120 mg/L,可同化氮源4种、碳源10种;其余3株非酿酒酵母的耐受及发酵特性优于陆生伊萨酵母低于戴尔有孢圆酵母;陆生伊萨酵母发酵速率在第2天达到最大值,其余4株酵母均在第3天达到发酵高峰。     

不同酵母菌发酵产油脂及脂肪酶的研究

通过摇瓶发酵研究了健强地霉、伯顿拟内孢霉、发酵性丝孢酵母油脂积累及脂肪酶活力.考察并比较了不同酵母菌的油脂合成及脂肪酶活力差别,通过酸热法破碎细胞提取油脂,采用橄榄油法测定发酵液和细胞中的脂肪酶活力.     

产朊假丝酵母高产GSH发酵条件优化研究

对产朊假丝酵母发酵产GSH进行研究,考察了胞内GSH的抽提方法、培养基组成及补加葡萄糖对GSH产量的影响。结果显示:最佳的抽提方法为乙醇法;酵母粉与硫酸铵对胞内谷胱甘肽含量影响最大,以硫酸铵为氮源时GSH含量可达到25.48mg/g;补加葡萄糖的时间为接种后10h、补加量为16mL时。最佳条件下得到菌体干重为8.14g/L,通过摇瓶发酵GSH产量为113.45mg/L,GSH产量提高了2.89倍。     

真养产碱杆菌发酵生产聚β-羟基丁酸(PHB)的研究

对真养产碱杆菌（Ａｌｃａｌｉｇｅｎｅｓｅｕｔｒｏｐｈｕｓ）ＮＣＩＭＢ１１５９９在１０Ｌ发酵罐中利用葡萄糖作为唯一碳源发酵生产聚β－羟基丁酸（ＰＨＢ）的发酵过程进行了研究。在以葡萄糖为唯一碳源的发酵中,分别在缺氧、限氧、限磷情况下及限磷和缺氧情况下对菌体生长及ＰＨＢ积累规律进行了研究。实验表明,氧和磷在菌体生长及ＰＨＢ的积累过程中起着重要作用。缺氧不利于菌体生长及积累ＰＨＢ;在一定程度上限制溶解氧则可促进ＰＨＢ的积累;在供氧充足时,限磷有利于ＰＨＢ大量积累;而限磷和缺氧条件下则抑制菌体生长和ＰＨＢ积累。采用限磷法发酵生产ＰＨＢ,经７２．５ｈ后得到菌体细胞干重为１３８．２ｇ／Ｌ,ＰＨＢ含量为１１１．８ｇ／Ｌ,ＰＨＢ占细胞干重８０．９％。     

连锁经营企业的战略溯源

"战略"一词起源于兵法,指将帅的智谋,中国古代,"战"与"略"是分别使用的."战"指战争,战斗,"略"指策划,计划,谋略.     

保龄宝为人类健康谱写新篇章——山东保龄宝生物公司发展低聚糖及糖醇产品纪实

<正> 在我国食品发酵行业中,山东保龄宝生物公司开创我国生物功能糖源的先河,闯出了一条改革、创新、发展高新技术产业化的开拓之路。这个集科、工、贸于一体的重点高新技术企业,主要生产国际流行的新型功能性生物糖源——IMO900低聚糖和糖醇系列产品。去年实现销售收入3.2亿元,出口创汇100多万美元,实现利税4,180万元,成为我国目前生产生物功能性糖源——低聚糖系列产品市场占有率极高的先进企业。     

Comparison of source apportionment and source sensitivity of ozone in a three-dimensional air quality model

The ozone source apportionment technology (OSAT) estimates the contributions of different sources to ozone concentrations using a set of tracers for NOx, total VOCs, and ozone and an indicator that ascribes instantaneous ozone production to NOx or VOCs. These source contributions were compared to first-order sensitivities obtained by the decoupled direct method (DDM) for a three-dimensional simulation of an ozone episode in the Lake Michigan region. The cut-point for the OSAT indicator between VOC- and NOx-sensitive ozone production agrees well with the DDM sensitivities to VOC and NOx. In a ranking of the most important contributors to ozone concentrations >80 ppb, the OSAT and DDM results agreed on four of the top five contributors on average. The spatial distributions of the sensitivities and source contributions are similar, and the OSAT and DDM results for ozone >80 ppb correlate well. However, the source contributions ascribe substantially less relative importance to anthropogenic emissions and greater relative importance to the boundary concentrations than do the sensitivities. In regions where NOx inhibits ozone formation and the sensitivity is negative, the source contribution is small and positive. For the same subdivision of the emissions, the OSAT is 14 times faster than the DDM, but the DDM has greater flexibility in defining which emissions to include and generates results for species other than ozone. The first-order sensitivities explain, on average, 70% of the ozone concentrations.     

Carbon source induces growth of stationary phase yeast cells,independent of carbon source metabolism

Nutrients regulate the proliferation of many eukaryotic cells: in the absence of sufficient nutrients vegetatively growing cells will enter stationary (G₀ like) phase; in the presence of sufficient nutrients non-proliferative cells will begin growth. Previously we have shown that glucose is the critical nutrient which stimulates a variety of growth-related events in the yeast Saccharomyces cerevisiae (Granot and Snyder, 1991). This paper describes six new aspects of the induction of cell growth events by nutrients in S. cerevisiae. First, all carbon sources tested, both fermentable and non-fermentable, induce growth-related events in stationary phase cells, suggesting that the carbon source is the critical nutrient which stimulates growth. Second, the continuous presence of glucose is not necessary for the induction of growth events, but rather a short ‘pulse’ of glucose followed by an incubation period in water will induce growth events. Third, growth stimulation by glucose occurs in the absence of the SNF3 high affinity glucose transporter. Fourth, growth stimulation occurs independent of carbon source phosphorylation and carbon source metabolism. Fifth, growth induction by carbon source does not require protein synthesis or extracellular calcium. Sixth, following stimulation by carbon source, the cells remain induced for more than 2 h after removal of the carbon source. We suggest a general model in which different carbon sources act as signals to induce the earliest growth events during or following its entry into the cell and that these growth events do not depend upon metabolism of the carbon source.