酵母菌属间原生质体融合构建高温酵母菌株

酿酒酵母(Saccharomyces cerevisiae) A001和克鲁维酵母(Kluyveromyces sp.) Y034属间原生质体融合构建高温酵母菌株。对制备高再生活性原生质体及融合子细胞形态、生理化特征、同工酶性质、遗传稳定性和高温发酵等方面进行了研究。结果表明,融合子AY023和AY680遗传性能稳定,表达了双亲优良性状,获得了在45℃培养条件下产酒率7.4%的属间融合菌株,是目前已见文献报道的产酒率最高的高温(45℃)酵母菌株。     

耐温酵母与酿酒酵母的属间融合及融合株的高温乙醇发酵

利用原生质体融合技术进行耐温的克鲁维酵母（Ｋｌｕｙｖｅｒｏｍｙｃｅｓ Ｙ０３４）与酿酒酵母（Ｓａｃｃｈａｒｏｍｙｃｅｓ ｃｅｒｅｕｉｓｉａｅ Ａ００１） 的属间融合,获得属间隔合子ＡＹ０６８。该融合株在４５℃下进行高温乙酵发酵,结果表明融合株表达了双亲耐温和产酒率高的特性。通过正交试验优化培养基成分,表明蛋东用量对菌体热抗性差异显著。比较了不同温度条件下,菌体生物量、糖利用率、ｐＨ因素与酒精产率的     

克鲁维酵母与酿酒酵母属间原生质体融合构建高温酵母菌株

通过ＰＥＧ诱导碘乙酸灭活呼吸缺陷克鲁维酵母原生质体与酿酒酵母原生质体融合,获得４５℃发酵产酒率高达８．７％的高温酵母菌株ＡＹ００６。线粒体缺失和氯霉素抑制可显著降低高密度原生质体回复抑制效应。对融合子菌落形态,同工酶性质和高温发酵等方面分析,融合株表达了耐温和高产酒率双亲优良性状,证实其杂种特征。     

酿酒酵母单倍体与双倍体原生质体的融合

本文报道用酿酒酵母(Saccharomyces cerevisiae)原生质体融合,得到营养互补的融合子为三倍体,其生长速度、发酵速率均较亲株提高1—2倍。部分融合子酒精的产量高于亲株,同时高于目前使用的酒精发酵生产菌株。     

克鲁维酵母与酿酒酵母属问原生质体融合构建高温酵母菌株*

通过PEG诱导碘乙酸灭活呼吸缺陷克鲁维酵母（Kluyveromycessp．Y034）原生质体与酿酒酵母（SaccharomycescerevisiaeA001）原生质体融合,获得45℃发酵产酒率高达8．7％的高温酵母菌株AY006。线粒体缺失和氯霉素抑制可显著降低高密度原生质体回复抑制效应。对融合子菌落形态、同工酶性质和高温发酵等方面分析,融合株表达了耐温和高产酒率双亲优良性状,证实其杂种特征。     

酿酒酵母单倍体与双倍体原生质体的融合*

本文报道用酿酒酵母(Saccharomyces cerevisiae)原生质体融合,得到营养互补的融合子为三倍体,其生长速度、发酵速率均较亲株提高1—2倍。部分融合子酒精的产量高于亲株,同时高于目前使用的酒精发酵生产菌株。     

新型细胞标记技术在酿酒酵母原生质体融合育种中的应用研究

本研究用酿酒酵母原生质体融合技术使两株酵母发生融合,通过用营养要求测定,交配型测定、细胞体积测定、DNA含量测定,筛选出13株融合株,再经免疫测定,得到同样的鉴定结果.表明免疫测定技术在酿酒酵母原生质体融合育种中作为亲本细胞标记是可行的,具有较高实用价值.     

电场诱导营养缺陷型酵母原生质体的融合

本文以酿酒酵母营养缺陷型单倍体菌株; Jz-25,a,ura。和Jz-22,a,trp’ade一的原生质体为材料,采用改进的大尺寸电融合小池,以频率为1MHz,强度为450V／cm的正弦交变电场作电介质电泳,使原生质体沿电力线方向排列成串,建立起质膜间的紧密接触;接着以高强度4．5kv／cm、短时程40μs的Rc放电脉冲触发并列质膜的可逆电击穿,引起膜的通透性瞬时增大,从而导致原生质体的融合．为了进一步增大从电极间取出的融合体数目,而克服由于增高交变电场引起的使溶液过热的副作用,实验中还设计了以PEG聚集原生质体后,加高强度7．0kv／cm短时程45μs的可逆电击穿脉冲触发融合的程序。实验结果表明;上述两种电融合程序的融台频率都要比以相同材料所作的纯PEG对照实验的融合频率有所提高。通过对融合产物作交配型检验和测量细胞的尺寸,初步可以证明融合子在质融后已发生核配,产生出二倍体菌株。看来细胞电融台方法可成为一种实际应用的技术。     

酿酒酵母和产朊假丝酵母原生质体的形成、再生及属间融合

使用由亚硝基胍诱变所得到的营养缺陷型作为单倍体融合亲株的核基因标记,同时也采用线粒体球红霉素抗性突变株的小菌落形式作为融合亲株的线粒体基因标记。酿酒酵母(Saccharomyces cerevisiae)和产朊假丝酵母(Candida utilis)两亲株原生质体的制备是用对数生长早期的细胞在蜗牛酶和0.7M KCl及β-巯基乙醇或二巯基苏糖醇的作用下完成的。二者的原生质体的形成率在30—60分钟内达到90—99％。原生质体再生率,酿酒酵母最高为29—35％,产朊假丝酵母为7.5％。两亲株的原生质体在35％PEG(M.W.6,000),10mM CaCl_2条件下被诱导融合。在基础培养基上,长出以营养互补为标记的融合菌株。融合频率为10~(-5)—10~(-6)。试验表明,这些融合菌株具有杂种的性质。其中一株杂合子在同化D-木糖、纤维二糖等的能力上比亲株明显增强。     

Acquisition of thermotolerant yeast Saccharomyces cerevisiae by breeding via stepwise adaptation

A thermotolerant Saccharomyces cerevisiae yeast strain, YK60‐1, was bred from a parental strain, MT8‐1, via stepwise adaptation. YK60‐1 grew at 40°C, a temperature at which MT8‐1 could not grow at all. YK60‐1 exhibited faster growth than MT8‐1 at 30°C. To investigate the mechanisms how MT8‐1 acquired thermotolerance, DNA microarray analysis was performed. The analysis revealed the induction of stress‐responsive genes such as those encoding heat shock proteins and trehalose biosynthetic enzymes in YK60‐1. Furthermore, nontargeting metabolome analysis showed that YK60‐1 accumulated more trehalose, a metabolite that contributes to stress tolerance in yeast, than MT8‐1. In conclusion, S. cerevisiae MT8‐1 acquired thermotolerance by induction of specific stress‐responsive genes and enhanced intracellular trehalose levels. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1116–1123, 2013     

原生质体融合构建耐温酵母菌株(英文)

耐温的克鲁维酵母（Ｙ０３４）与产酒率高的酿酒酵母（Ａ００１）进行属间原生质体融合构建耐温酵母菌株,经ＤＴＴ分段预处理获得大量具再生活性原生质体对融合株ＡＹ０２３等进行了乙醇脱氢酶同工酶,麦芽糖同化,遗传稳定性及高温发酵分析,融合株ＡＹ０２３表达了双亲遗传特性。在４５℃高温发酵条件,乙醇产率高达７．４％,是目前已见文献报道的产酒率最高的耐温（４５℃）酵母菌株     

Characterization of gamma-glutamylamidase-glutaminase activity in Saccharomyces cerevisiae

In a foregoing paper we have shown the presence in the yeast Saccharomyces cerevisiae of an enzyme catalyzing the hydrolysis of L-gamma-glutamyl-p-nitroanilide, but apparently distinct from gamma-glutamyltranspeptidase. The cellular level of this enzyme was not regulated by the nature of the nitrogen source supplied to the yeast cell. Purification was attempted, using ion exchange chromatography on DEAE Sephadex A 50, salt precipitations and successive chromatographies on DEAE Sephadex 6B and Sephadex G 100. The apparent molecular weight of the purified enzyme was 14,800 as determined by gel filtration. As shown by kinetic studies and thin layer chromatography, the enzyme preparation exhibited only hydrolytic activity against gamma-glutamylarylamide and L-glutamine with an optimal pH of about seven. Various gamma-glutamylaminoacids, amides, dipeptides and glutathione were inactive as substrates and no transferase activity was detected. The yeast gamma-glutamylarylamidase was activated by SH protective agents, dithiothreitol and reduced glutathione. Oxidized glutathione, ophtalmic acid and various gamma-glutamylaminoacids inhibited competitively the enzyme. The activity was also inhibited by L-gamma-glutamyl-o-(carboxy)phenylhydrazide and the couple serine-borate, both transition-state analogs of gamma-glutamyltranspeptidase. Diazooxonorleucine, reactive analog of glutamine, inactivated the enzyme. The physiological role of yeast gamma-glutamylarylamidase-glutaminase is still undefined but is most probably unrelated to the bulk assimilation of glutamine by yeast cells.     

Improved ethanol production of a newly isolated thermotolerant Saccharomyces cerevisiae strain after high-energy-pulse-electron beam

Aims: To isolate thermotolerant Saccharomyces cerevisiae with high‐energy‐pulse‐electron (HEPE) beam, to optimize the mutation strain fermentation conditions for ethanol production and to conduct a preliminary investigation into the thermotolerant mechanisms. Methods and Results: After HEPE beam radiation, the thermotolerant S. cerevisiae strain Y43 was obtained at 45°C. Moreover, the fermentation conditions of mutant Y43 were optimized by L3³ orthogonal experiment. The optimal glucose content and initial pH for fermentation were 20% g l^?1 and 4·5, respectively; peptone content was the most neglected important factor. Under this condition, ethanol production of Y43 was 83·1 g l^?1 after fermentation for 48 h at 43°C, and ethanol yield was 0·42 g g^?1, which was about 81·5% of the theoretical yield. The results also showed that the trehalose content and the expression of the genes MSN2, SSA3 and TPS1 in Y43 were higher than those in the original strain (YE0) under the same stress conditions. Conclusions: A genetically stable mutant strain with high ethanol yield under heat stress was obtained using HEPE. This mutant may be a suitable candidate for the industrial‐scale ethanol production. Significance and Impact of the Study: High‐energy‐pulse‐electron radiation is a new efficient technology in breeding micro‐organisms. The mutant obtained in this work has the advantages in industrial ethanol production under thermostress.     

灭活原生质体融合选育木糖、葡萄糖共发酵酿酒酵母工程菌

为了选育高效利用木糖、葡萄糖共发酵,并使乙醇产量有所提高的酿酒酵母工程菌株。以酿酒酵母Saccharomyces cerevisiae W5和休哈塔假丝酵母Candida shehatae 20335为亲本株,确定了双亲株原生质体灭活剂量,并进行原生质体融合获得融合子,用高效液相色谱（HPLC）测定融合子以木糖、葡萄糖单碳源及混合碳源发酵时的乙醇得率。结果表明,获得一株发酵性能优良的融合子HDY2-14,其利用木糖和葡萄糖单碳源发酵的乙醇得率分别为0.213g/g和0.257g/g,混合碳源发酵的乙醇得率为0.310g/g,其中混合碳源乙醇得率比亲本株W5和20335的乙醇得率分别提高了20.2%和15.2%。