The effect of different surfactants on α-arbutin bio-catalytic synthesis by Xanthomonas maltophilia BT-112 was investigated.Tween80 was the best when compared with different kinds of surfactants at different concentr...The effect of different surfactants on α-arbutin bio-catalytic synthesis by Xanthomonas maltophilia BT-112 was investigated.Tween80 was the best when compared with different kinds of surfactants at different concentrations and times of surfactant addition.Experimental results showed that the suitable conditions were as follows:adding 3 g·L-1 Tween80 during the 12 hours from the start of fermentation,fed-batch in three times,1 g·L-1 every time.Under the conditions mentioned above,the product yield reached 96.2% against hydroquinone and increased by 3.53% and hydroquinone concentration reached 60 mmol·L-1 and increased by 25.0% as compared with the case without adding surfactant.The fermentation period was 36 h,25% less than the case without adding surfactant.展开更多
A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions f...A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions for producing transgenic fish. Several key elements were found to have significant effects on the integration of exogenous gene. These elements include forms and doses of pcMTsGH gene microinjected, stages of embryo at which microinjection conducted and pretreatment of fertilized eggs for microinjection. The results show that, in producing transgenic fish, (1) the best time for microinjection is late onecell stage, (2) the most appropriate dose of pcMTsGH gene for microinjection is around 106～107 copies; (3) the hatching rate rises up when the gene is microinjected into the eggs whose chorions are removed, but the integration rate has no significant changes before and after the removal of egg chorions.展开更多
文摘The effect of different surfactants on α-arbutin bio-catalytic synthesis by Xanthomonas maltophilia BT-112 was investigated.Tween80 was the best when compared with different kinds of surfactants at different concentrations and times of surfactant addition.Experimental results showed that the suitable conditions were as follows:adding 3 g·L-1 Tween80 during the 12 hours from the start of fermentation,fed-batch in three times,1 g·L-1 every time.Under the conditions mentioned above,the product yield reached 96.2% against hydroquinone and increased by 3.53% and hydroquinone concentration reached 60 mmol·L-1 and increased by 25.0% as compared with the case without adding surfactant.The fermentation period was 36 h,25% less than the case without adding surfactant.
文摘A recombinant plasmid (pcMTsGH) containing the common carp methlothionein promoter (cMT) and salmon growth hormone gene (sGH) was microinjected into common carp fertilized eggs and embryos to optimize the conditions for producing transgenic fish. Several key elements were found to have significant effects on the integration of exogenous gene. These elements include forms and doses of pcMTsGH gene microinjected, stages of embryo at which microinjection conducted and pretreatment of fertilized eggs for microinjection. The results show that, in producing transgenic fish, (1) the best time for microinjection is late onecell stage, (2) the most appropriate dose of pcMTsGH gene for microinjection is around 106～107 copies; (3) the hatching rate rises up when the gene is microinjected into the eggs whose chorions are removed, but the integration rate has no significant changes before and after the removal of egg chorions.
文摘利用本实验室生产的粘多糖A对辽河重质稠油进行乳化降黏试验,系统考察油水质量比、多糖浓度、乳化温度、乳化转速和乳化时间对稠油乳化降黏的影响。结果表明:将油水质量比6∶4,多糖质量浓度150 mg/L的稠油溶液放入温度25℃、转速160 r/min的摇床乳化6 h,稠油黏度由87000 m Pa·s降至310 m Pa·s,降黏率达到99.6%。此外,通过对乳化降黏后稠油破乳处理研究发现,稠油在室温静置24 h后即可实现油水分离,且破乳后的多糖水溶液可以重复使用2批次,显著降低了多糖乳化剂及后续稠油脱出水处理成本。因此,该粘多糖A可广泛应用于稠油乳化降黏开采和输送领域。
