A Lactobacillus buchneri GBS3 strain isolated from the traditional Chinese pickles was used for the production of 3-phenyllactic acid(PLA), an important compound with antimicrobial activities against a wide species of...A Lactobacillus buchneri GBS3 strain isolated from the traditional Chinese pickles was used for the production of 3-phenyllactic acid(PLA), an important compound with antimicrobial activities against a wide species of grampositive and gram-negative bacteria and some fungi. The growth performance of this strain in the de Man, Rogosa and Sharpe(MRS) medium, the production of metabolites of valuable organic acids, and the biosynthesis of PLA using this strain as the whole-cell biocatalyst and phenylpyruvic acid(PPA) as the precursor, were investigated experimentally. The uniform design method with overlay sampling was developed for the optimization of the biotransformation conditions. The results showed that although it produced naturally lactic acid with the maximum concentration of 1.84 g·L^(-1) and PLA with the concentration of 0.015 g·L^(-1) after 66 to 72 h cultivation in MRS broth by fermentation, the present strain displayed an effective utilization ability by transforming PPA to PLA. By the uniform design method with overlay sampling for the design and optimization of transformation conditions, a maximum yield of 10.93 g·L^(-1) PLA with the mole conversion ratio of 83.07% from PPA to PLA was achieved under the optimized condition, i.e., 20 g·L^(-1) glucose, 270 g·L^(-1) cells, 13 g·L^(-1) PPA, pH 8.0 and the reaction time of 15 h, indicating that Lactobacillus buchneri GBS3 was an interesting strain for the biosynthesis of PLA via the microbial transformation. The prediction of PLA yield under different conditions was achieved successfully based on the limited information of only a small number of experiments by the uniform design with overlay sampling. Therefore, the present methodology is effective and helpful for the optimization of the biosynthesis processes of PLA.展开更多
[Objective]To compare the effectiveness of Lactobacillus buchneri（LB）,alone or in combination with Lactobacilllus plantarum（LP）at ensiling on the fermentation,aerobic stability and nutritive value of whipgrass（He...[Objective]To compare the effectiveness of Lactobacillus buchneri（LB）,alone or in combination with Lactobacilllus plantarum（LP）at ensiling on the fermentation,aerobic stability and nutritive value of whipgrass（Hemarthria compressa（L.f.）R.Br.）silage in 1.5-l mili-silos and 50-l plastic containers.[Method]Treatments comprised control（no additives）,LP,LB and LP ＋ LB.After 90 d of storage,overall,inoculation increased the concentration of acetic and 1,2-propanediol,but it reduced the concentrations of lactic acid,water suluble carbohydrates and enthanol.[Result]The whipgrass silages treated with LB had higher acetic acid contents than the control or LP treated silages,and were free of mold,whereas the top layers of the control or LP-treated silages were moldly.In an aerobic stability test the LB-treated silages were stable,whereas those treated with LP deteriorated.In the whipgrass silages the effects of LB made less CO 2 production and stable pH.[Conclusion]It is concluded that LB has a potential as a whipgrass silage additive that protects the silage upon aerobic exposure.展开更多
We evaluated the fermentation products, the gaseous and effluent losses of sugarcane silages without calcium oxide (CaO) or with CaO addition, at the levels of zero, 0.8%, 1.6% and 2.4%, in association with the microb...We evaluated the fermentation products, the gaseous and effluent losses of sugarcane silages without calcium oxide (CaO) or with CaO addition, at the levels of zero, 0.8%, 1.6% and 2.4%, in association with the microbial additive Lactobacillus buchneri inoculated at the levels of zero, 50.000, 100.000 e 150.000 ufc/g of sugarcane, wet bases. The variety RB855536, harvested after 12 months of first growth was used. The experiment design was the completely randomized design, in a 4 × 4 factorial arrangement. They were evaluated in the silages, the contents of volatile fatty acids, lactic acid, ethanol, and the pH, as well as the gaseous and effluent losses. In the analysis of the data, the SAS system was utilized. It was observed on interaction effect of the chemical and microbial additive over the contents of lactic acid, acetic acid, propionic acid, butyric acid, ethanol and over the gaseous and effluents losses. However, there was no interaction effect regarding to pH. When it was observed on interaction effect of additives, the effects of the levels of one additive were evaluated by regression analysis in each level of each other, and vice-versa. The level 1.6% of CaO associated to the level 50,000 ufc/g of natural matter of Lactobacillus buchneri provided adequate levels of lactic acid (superior to 4.5%), and of acetic acid (around 1%), moderate content of propionic acid (0.55%), low content of butyric acid (0.05%) and controlled the production of ethanol and the gaseous and effluent losses. The pH of the silages were influenced by CaO addition, but were not affected consistently by microbial inoculation.展开更多
基金Supported partially by the National Natural Science Foundation of China(21576240)the Natural Science Foundation of Zhejiang Province(LZ14B060001,LY16B060011)
文摘A Lactobacillus buchneri GBS3 strain isolated from the traditional Chinese pickles was used for the production of 3-phenyllactic acid(PLA), an important compound with antimicrobial activities against a wide species of grampositive and gram-negative bacteria and some fungi. The growth performance of this strain in the de Man, Rogosa and Sharpe(MRS) medium, the production of metabolites of valuable organic acids, and the biosynthesis of PLA using this strain as the whole-cell biocatalyst and phenylpyruvic acid(PPA) as the precursor, were investigated experimentally. The uniform design method with overlay sampling was developed for the optimization of the biotransformation conditions. The results showed that although it produced naturally lactic acid with the maximum concentration of 1.84 g·L^(-1) and PLA with the concentration of 0.015 g·L^(-1) after 66 to 72 h cultivation in MRS broth by fermentation, the present strain displayed an effective utilization ability by transforming PPA to PLA. By the uniform design method with overlay sampling for the design and optimization of transformation conditions, a maximum yield of 10.93 g·L^(-1) PLA with the mole conversion ratio of 83.07% from PPA to PLA was achieved under the optimized condition, i.e., 20 g·L^(-1) glucose, 270 g·L^(-1) cells, 13 g·L^(-1) PPA, pH 8.0 and the reaction time of 15 h, indicating that Lactobacillus buchneri GBS3 was an interesting strain for the biosynthesis of PLA via the microbial transformation. The prediction of PLA yield under different conditions was achieved successfully based on the limited information of only a small number of experiments by the uniform design with overlay sampling. Therefore, the present methodology is effective and helpful for the optimization of the biosynthesis processes of PLA.
基金Supported by the National Science and TechnologySupport Program of the Twelfth Five-Year Plan (2011BADITB03)
文摘[Objective]To compare the effectiveness of Lactobacillus buchneri（LB）,alone or in combination with Lactobacilllus plantarum（LP）at ensiling on the fermentation,aerobic stability and nutritive value of whipgrass（Hemarthria compressa（L.f.）R.Br.）silage in 1.5-l mili-silos and 50-l plastic containers.[Method]Treatments comprised control（no additives）,LP,LB and LP ＋ LB.After 90 d of storage,overall,inoculation increased the concentration of acetic and 1,2-propanediol,but it reduced the concentrations of lactic acid,water suluble carbohydrates and enthanol.[Result]The whipgrass silages treated with LB had higher acetic acid contents than the control or LP treated silages,and were free of mold,whereas the top layers of the control or LP-treated silages were moldly.In an aerobic stability test the LB-treated silages were stable,whereas those treated with LP deteriorated.In the whipgrass silages the effects of LB made less CO 2 production and stable pH.[Conclusion]It is concluded that LB has a potential as a whipgrass silage additive that protects the silage upon aerobic exposure.
文摘We evaluated the fermentation products, the gaseous and effluent losses of sugarcane silages without calcium oxide (CaO) or with CaO addition, at the levels of zero, 0.8%, 1.6% and 2.4%, in association with the microbial additive Lactobacillus buchneri inoculated at the levels of zero, 50.000, 100.000 e 150.000 ufc/g of sugarcane, wet bases. The variety RB855536, harvested after 12 months of first growth was used. The experiment design was the completely randomized design, in a 4 × 4 factorial arrangement. They were evaluated in the silages, the contents of volatile fatty acids, lactic acid, ethanol, and the pH, as well as the gaseous and effluent losses. In the analysis of the data, the SAS system was utilized. It was observed on interaction effect of the chemical and microbial additive over the contents of lactic acid, acetic acid, propionic acid, butyric acid, ethanol and over the gaseous and effluents losses. However, there was no interaction effect regarding to pH. When it was observed on interaction effect of additives, the effects of the levels of one additive were evaluated by regression analysis in each level of each other, and vice-versa. The level 1.6% of CaO associated to the level 50,000 ufc/g of natural matter of Lactobacillus buchneri provided adequate levels of lactic acid (superior to 4.5%), and of acetic acid (around 1%), moderate content of propionic acid (0.55%), low content of butyric acid (0.05%) and controlled the production of ethanol and the gaseous and effluent losses. The pH of the silages were influenced by CaO addition, but were not affected consistently by microbial inoculation.
