发酵甜高粱汁耐高浓度酒精酵母菌的选育

采用负染色计数法从非自然诱变菌株中成功地选育了一株以C4植物甜高粱汁做基质发酵生产液体生物燃料(酒精)的酵母菌株,产酒率最高达12.80%(V/V).     

发酵戊糖产酒精酵母菌株的选育

介绍了一种新的发酵戊糖产酒酵母菌种筛选方法并利用该方法筛选出一株性能优良的发酵戊糖酵母蓖株Z8,该菌株性能测试结果为：产酒精能力相当于发酵戊糖理论产量的60．0％,耐酒精能力14％（V／V）,在温度高达42℃的条件下仍能正常发酵,初步鉴定该菌株为管囊酵母（Pachysolen tannophilus)。     

生淀粉高浓度酒精发酵的研究

本研究利用国内常用的糖化酶制剂糖化生玉米面中的淀粉,同时接种酵母菌,在30℃下,探讨了玉米淀粉的高浓度酒精发酵工艺。选择到了一株产高浓度酒精酵母菌,H0菌株。发酵温度为30℃、pH4一s、加糖化酶量为每克原料300单位、酵母接种量3％(v／v)和原料加量为33．0％(w／v)时,这株酵母菌在70小时内可产生17．5％(v／v)的乙醇。如果原料加量为36．0％(w／v)时,该菌株在96小时内可以产生18．O％(v／v)的乙醇。在前一种加料情况下,成熟发酵醪中的pH为5、残还原糖为O．19％、残总糖为3．5“。在后一种加料情况下,成熟发酵醪中的pH为5、残还原糖为0．81％、残总糖为5．1％。     

酵母菌和发酵条件对酒精连续发酵的影响

从多株酒精酵母菌种中筛选出Ｓ．ｃｅｒｅｖｉｓｉｎｅ ＫＧ作为加续发酵菌株,该劳动力株经耐酸驯化,提高了抵抗不利环境的能力。本论文还探讨了二氧化碳、氧气对酒精对发酵过程的影响。认为氧气是一关键性的影响因素。在另一方面,在酒精连续发酵过程中使用带有细胞循环的双罐系统,酒精生产强度达到３０．５ｇ／Ｌ．ｄ。     

酵母菌株和发酵条件对酒精连续发酵的影响

从多株酒精酵母菌种中筛选出S．cerevisiaeKG作为连续发酵菌株,该菌株经耐酸驯化,提高了抵抗不利环境的能力。本论文还探讨了二氧化碳、氧气对酒精发酵过程的影响,认为氧气最一关键性的影响因素。在另一方面,在酒精连续发酵过程中使用带有细胞循环的双罐系统,酒精生产强度达到30．5g／L·h。     

耐高温酵母菌株的分离、鉴定及其酒精发酵初步研究

从 38 1个自然样品中筛选得到 2株耐高温酵母THFY 4和THFY 1 6。THFY 4能够在51℃ ,含 30 %葡萄糖的培养基中生长 ;THFY 1 6能够在 45℃ ,30 %葡萄糖的培养基中生长。经初步鉴定 ,THFY 4为克鲁维属酵母 ,THFY 1 6为酵母属酵母。进一步的 37℃发酵实验证明 ,THFY 4在静置条件下的发酵性能很差 ,发酵 60h只能从 2 0 %的葡萄糖产生 4 88% (v v)的酒精 ;而THFY 1 6在相同的条件下从 2 0 %的葡萄糖中产生 1 1 44%     

呼吸缺陷型耐糖耐高温酒精酵母菌种的筛选

采用紫外诱变和2,3,5-氯化三苯基四氮唑(TTC)鉴别性培养基,从市售酒精活性酵母粉中分离出13株呼吸缺陷型突变株.通过进一步筛选,最终筛选出一株呼吸缺陷型耐糖、耐高温的高效酒精酵母菌株,编号为T11.该菌株菌落表面湿润,乳白色,小且圆;细胞椭圆形(2.5～5.0μ×3.75～6.25μ),出芽繁殖,在25%(W/V)葡萄糖发酵液,起始pH 5.5,40℃条件下发酵,酒精发酵产酒精率和糖利用率分别可达45.54%和98.01%.     

生淀粉降解酶菌株的选育和酒精发酵试验

从样品中分离到128株菌,从中选育到一株分解甘薯生淀粉能力强的45号黑曲霉菌株。以此菌株为出发菌株经过紫外线、氯化锂多次复合处理,得到154号突变株,其降解甘薯生淀粉酶活力为219.4u/g,比出发菌株提高49.7%o用于甘薯生淀粉糖化、酒精发酵,出酒率为36.3%,接近传统工艺。     

Ethanol production from sweet sorghum juice using very high gravity technology: Effects of carbon and nitrogen supplementations

Ethanol production from sweet sorghum juice by Saccharomyces cerevisiae NP01 was investigated under very high gravity (VHG) fermentation and various carbon adjuncts and nitrogen sources. When sucrose was used as an adjunct, the sweet sorghum juice containing total sugar of 280 g l⁻¹, 3 g yeast extract l⁻¹ and 5 g peptone l⁻¹ gave the maximum ethanol production efficiency with concentration, productivity and yield of 120.68 ± 0.54 g l⁻¹, 2.01 ± 0.01 g l⁻¹ h⁻¹ and 0.51 ± 0.00 g g⁻¹, respectively. When sugarcane molasses was used as an adjunct, the juice under the same conditions gave the maximum ethanol concentration, productivity and yield with the values of 109.34 ± 0.78 g l⁻¹, 1.52 ± 0.01 g l⁻¹ h⁻¹ and 0.45 ± 0.01 g g⁻¹, respectively. In addition, ammonium sulphate was not suitable for use as a nitrogen supplement in the sweet sorghum juice for ethanol production since it caused the reduction in ethanol concentration and yield for approximately 14% when compared to those of the unsupplemented juices.     

The production‐ecological sustainability of cassava,sugarcane and sweet sorghum cultivation for bioethanol in Mozambique

We present an approach for providing quantitative insight into the production‐ecological sustainability of biofuel feedstock production systems. The approach is based on a simple crop‐soil model and was used for assessing feedstock from current and improved production systems of cassava for bioethanol. Assessments were performed for a study area in Mozambique, a country considered promising for biomass production. Our focus is on the potential role of smallholders in the production of feedstock for biofuels. We take cassava as the crop for this purpose and compare it with feedstock production on plantations using sugarcane, sweet sorghum and cassava as benchmarks. Production‐ecological sustainability was defined by seven indicators related to resource‐use efficiency, soil quality, net energy production and greenhouse gas (GHG) emissions. Results indicate that of the assessed systems, sugarcane performed better than cassava, although it requires substantial water for irrigation. Targeted use of nutrient inputs improved sustainability of smallholder cassava. Cassava production systems on more fertile soils were more sustainable than those on less fertile soils; the latter required more external inputs for achieving the same output, affecting most indicators negatively and reducing the feasibility for smallholders. Cassava and sweet sorghum performed similarly. Cassava production requires much more labour per hectare than production of sugarcane or sweet sorghum. Production of bioethanol feedstock on cultivated lands was more sustainable and had potential for carbon sequestration, avoiding GHG emissions from clearing natural vegetation if new land is opened.     

高粱总DNA导入春不麦稳定后代高分子量麦谷蛋白亚基的变化

通过花粉管通道法将高粱总ＤＮＡ导入春麦甘麦８号、陇春１３号和陇春１０号,经过多代选择获得了５个稳定的后代。在高分子量麦谷蛋白亚基分析中,甘麦８号后代８９１４４的高分子量麦谷蛋白亚基发生突变,较其受体多了５＋１０亚基,而少了２＋１２亚基;其它几个转基因后代与其受体比较,高分子量麦谷蛋白亚基组成未发生变化;但是,各亚基的相对较大变化。高分子量麦谷蛋白亚基的组成和各亚基含量的变化直接影响小麦品质。本研究     

高糖对线粒体乙醛脱氢酶2在大鼠心肌成纤维细胞中表达的影响

目的：观察心肌成纤维细胞是否存在线粒体乙醛脱氢酶2（ALDH2）的表达,探讨ALDH2在高糖诱导的心肌成纤维细胞引起纤维化发生中的作用。方法：原代培养心肌成纤维细胞,分为正常对照组（5.5 mmol/L）、正常+ALDH2激动剂Alda-1（20μmol/L）组、高糖组（30 mmol/L）、高糖+ Alda-1组。免疫荧光鉴定心肌成纤维细胞。各组细胞分别培养48 h后应用MTT法检测成纤维细胞增殖活力,RT-PCR和Western blot检测ALDH2 mRNA及蛋白的表达。结果：RT-PCR和Western blot结果显示心肌成纤维细胞ALDH2 mRNA和蛋白均有表达。与正常对照组相比,高糖组心肌成纤维细胞增殖能力提高（P < 0.01）,ALDH2蛋白表达下降（P < 0.05）;与高糖组相比,高糖+ Alda-1组心肌成纤维细胞增殖能力降低（P < 0.01）,ALDH2的蛋白表达增加（P < 0.05）。结论：心肌成纤维细胞存在ALDH2的表达,ALDH2激动剂Alda-1提高ALDH2的表达后可以抑制高糖引起的心肌成纤维细胞的增殖。     

大棚油桃授粉方式研究初报

2002年2-5月,研究利用蜜蜂、壁蜂花期传粉及人工授粉技术对大棚油桃艳光和潍甜1号的座果率及产量均有不同程度的提高;其中潍甜1号的座果率提高幅度最大。上述几种方法中,人工授粉的效果最好。     

离子束注入法诱变选育耐高糖衣康酸高产菌株

采用20keV不同剂量的低能氩离子束和氮离子束注入土曲霉T730,选育出耐高糖衣康酸高产菌株HA8。该菌株可以在蔗糖初始浓度为15％和20％的培养基中摇瓶发酵4～5d,产酸率分别达到9．2％和11．5％,糖酸转化率分别达到61．3％和57．5％,比出发菌株1．730的产酸率提高了74％。     

Effect of garlic oil extract on glutathione reductase levels in rats fed on high sucrose and alcohol diets: A possible mechanism of the activity of the oil

The effect on glutathione reductase activities of feeding garlic oil to white albino rats maintained on high sucrose and alcohol diets was studied. Whereas high sucrose and alcohol diets resulted in significant increases in the activity of glutathione reductase in liver, kidneys and serum, the presence of garlic oil restored the levels to near normal. It is proposed that the mechanism of this action of garlic oil involves the active principle, diallyl disulphide, which interacts in an exchange reaction with enzymes and substrates such as glutathione reductase and glutathione which contain thiol groups.     

The effect of levofloxacin concentration on the development and maintenance of antibiotic-resistant clones of Escherichia coli in chemostat culture

A levofloxacin-sensitive strain of Escherichia coli (broth MIC: 0.0625 mg l⁻¹) was grown in carbon-limited chemostat culture for 316 h (D=0.294 h⁻¹). Hyperresistant strains isolated after 58 and 91 generations of culture retained a 16- to 47-fold increase in tolerance to levofloxacin during antibiotic-free serial batch and continuous culture (20 generations, glucose-limited, D=0.2 h⁻¹). Isolates differed from the original strain in their maximum growth rates in the presence and absence of subinhibitory levels of levofloxacin, protein-banding profiles, and resistance to a range of antibiotics. Competition between resistant isolates and the original sensitive strain was studied in glucose-limited chemostat cultures (D=0.2 h⁻¹). At levofloxacin concentrations less than 0.03 mg l⁻¹, the sensitive strain outcompeted resistant isolates and displaced them from the culture, whereas the reverse was true at higher concentrations. These results have clinical and environmental implications for those administering levofloxacin. Journal of Industrial Microbiology & Biotechnology (2002) 29, 155–162 doi:10.1038/sj.jim.7000295 Received 26 September 2001/ Accepted in revised form 13 June 2002     

干旱区胡杨光合作用对高温和CO2浓度的响应

采用LI-6400便携式光合作用测定仪实测的塔里木河下游胡杨(Populus euphratica oliv)光合作用参数,探讨了不同地下水埋深下的胡杨光合作用对CO2浓度增加和温度升高的响应.结果表明:(1)CO2浓度升高减小了胡杨气孔导度,促进了光合速率、胞间CO2浓度和水分利用效率的增加,但不同地下水埋深下,胡杨光合作用参数对CO2浓度升高的响应不同,干旱环境(地下水埋深较深)下的响应程度大于水分适宜(地下水埋深浅)环境下的响应;(2) 高温引起胡杨气孔发生不完全关闭,导致了光合作用的光抑制发生,从而降低了胡杨光合速率,但降低程度受水分条件的影响,地下水埋深较深环境下的影响程度大于地下水埋深浅的;(3)地下水埋深是控制干旱区胡杨光合作用对CO2浓度和温度升高的根本因素,6m是胡杨生长正常的临界地下水埋深,地下水埋深>6m,胡杨即遭到水分胁迫,地下水埋深>7m,胡杨即受到了较严重的水分胁迫.