title: Effects of pretreatment on the microbial community and l-lactic acid production in vinasse fermentation.
abstract: Microwave-alkali and steam-alkali coupled pretreatments were carried out to improve the yield and optical purity of l-lactic acid produced using vinasse fermentation. Lactobacillus casei was inoculated into the system to initiate fermentation. Polymerase chain reaction denaturing gradient gel electrophoresis was used to analyze the microbial community during fermentation with and without the pretreatments. The original bacterial genus in vinasse was essentially inactivated, whereas L. casei became the dominant genus after 24h of fermentation. The system subjected to microwave-alkali coupled pretreatment released more reducing sugars and produced more lactic acid (up to 30.32g/L), which is twice that without pretreatment. In addition, the proportion of lactic acid in the organic acids also increased. The optical purity of the l-lactic acid produced under the microwave-alkali coupled pretreatment reached 91%, which is 2% higher than that under the steam-alkali coupled pretreatment and 7% higher than that under the control conditions. Therefore, the microwave-alkali coupled pretreatment is an effective method for the highly efficient bioconversion of vinasse into bioenergy.
authors.affiliation: Department of Environmental Engineering, University of Science and Technology Beijing, Beijing, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Liu
authors.forename: Qunhui
authors.initials: Q
authors.lastname: Wang
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Sun
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Ma
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tushiro
mesh_terms: D050260:Carbohydrate Metabolism; D004269:DNA, Bacterial; D058645:Denaturing Gradient Gel Electrophoresis; D005285:Fermentation; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D019344:Lactic Acid / Q000032:analysis / Q000378:metabolism*; D059013:Microbial Consortia; D016133:Polymerase Chain Reaction; D012972:Sodium Hydroxide / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D007220:Industrial Waste; D019344:Lactic Acid; D012972:Sodium Hydroxide