排序方式: 共有18条查询结果,搜索用时 15 毫秒
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不同时间流加番茄汁对红发夫酵母生产虾青素的影响 总被引:1,自引:0,他引:1
番茄红素作为虾青素合成的前体物质,适量添加对虾青素合成起到促进作用。由于成熟番茄汁中含有大量的番茄红素,可以作为番茄红素的替代品,而且番茄汁含有的其它营养物质对红发夫酵母的生长也有一定的积极作用。这样既促进了虾青素的合成,又节约了成本,故选择番茄汁作为流加物质。结果表明,培养36h时添加番茄汁,红发夫酵母72~120h生长状态平稳,且对提高虾青素含量和产量效果显著,培养96h虾青素含量高达1318μg/g,虾青素产量也达到最高,为17.87mg/L。 相似文献
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从提高酶活力和降低成本综合考虑,研究Na+、Ca2+子及液化温度和pH协同作用对耐高温α-淀粉酶的影响。以酶活力为指标,通过单因素和正交试验,优选出在Na+浓度60mg/kg,Ca2+浓度10mg/kg,温度90℃,pH 4.5条件下,相对酶活最高达到187%。 相似文献
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选择益力多乳酸饮料作为样品,从中筛选出能产γ-氨基丁酸的乳酸菌,初步鉴定为乳酸乳球菌乳酸亚种,γ-氨基丁酸产量为2.11 g/L.对该出发菌株进行微波诱变(700W,脉冲频率2450MHz)处理,得到1株突变菌株,γ-氨基丁酸产量达5.78g/L,经过多次传代稳定性较好. 相似文献
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通过PCR扩增了乙酸异戊酯高产菌Loq-c的脂肪酶基因Lip2,其序列与Gene Bank中的Candida cylindracea Lip2 gene(序列号X64704.1)的序列相似度最高,为89%。构建原核表达载体p QE-lip2,转化大肠杆菌E.coli BL21(DE3),获得了重组菌BL21(p QE-lip2)。经过表达条件探索,用SDS聚丙烯酰胺凝胶电泳分析,脂肪酶Lip2原核可溶表达最佳条件为:诱导温度30℃,IPTG使用浓度为1.5 mmol/L,150 r/min转速的条件下诱导表达5 h。 相似文献
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Synchronous hybrid transport network design 总被引:1,自引:1,他引:0
Delay, as an inevitable real-world phenomenon, is usually ignored in transport network design. A model of urban hybrid transport
system with stochastic delay was created on the basis of the idealized public transport system design. After formulating the
total trip time cost composed of accessing time in the sub-region of the city, waiting time at the public transport station,
and in-vehicle time in the public transit network, the analytical properties of the total trip time cost function were investigated.
The results show that in the urban hybrid transport network design, the total trip time cost reaches its approximate minimum
in a δ-neighbourhood of buffer time of 1.5 min, and that through modelling optimal delay in hybrid transport system, the maximal
synchronization can be achieved and operational efficiency and passenger satisfaction can be improved. The proposed modelling
and analytical investigations are attempts to contribute to more realistic modelling of future idealized public transport
system that involves more practical constraints.
Foundation item: Project (70671008) supported by the National Natural Science Foundation of China, Project (3340-74236000003) supported by
the Scientific Research Innovation Fund Project for Graduate Student of Hunan Province, China 相似文献