Michelz Beitel Susan, Fontes Coelho Luciana, Sass Daiane Cristina, Contiero Jonas
Department of Biochemistry and Microbiology, Institute of Bioscience, São Paulo State University (UNESP), São Paulo, SP, Brazil.
Associate Laboratory IPBEN, UNESP, Av. 24A 1515 CEP, 13506-900, Rio Claro, SP, Brazil.
Int J Microbiol. 2017;2017:4851612. doi: 10.1155/2017/4851612. Epub 2017 Sep 10.
The interest in the production of lactic acid has increased due to its wide range of applications. In the present study, the variables that affect fermentative D(-) lactic acid production were investigated: neutralizing agents, pH, temperature, inoculum percentage, agitation, and concentration of the medium components. An experimental design was applied to determine the optimal concentrations of the medium components and fermentation was studied using different feeding strategies. High production (122.41 g/L) and productivity (3.65 g/L·h) were efficiently achieved by in 54 h using a multipulse fed-batch technique with an initial medium containing 35 g/L of yeast extract (byproduct of alcohol production), 60 g/L of crystallized sugar, and 7.5 mL/L of salts. The fermentation process was conducted at 35°C and pH 6.0 controlled by NaOH with a 20% volume of inoculum and agitation at 125 rpm. The production of a high optically pure concentration of D(-) lactic acid combined with an environmentally friendly NaOH-based process demonstrates that is a promising strain for D(-) lactic acid production.
由于乳酸的广泛应用，人们对其生产的兴趣有所增加。在本研究中，对影响发酵生产D(-)乳酸的变量进行了研究：中和剂、pH值、温度、接种百分比、搅拌以及培养基成分浓度。应用实验设计来确定培养基成分的最佳浓度，并使用不同的补料策略研究发酵过程。使用多脉冲补料分批技术，在初始培养基含有35 g/L酵母提取物（酒精生产的副产品）、60 g/L结晶糖和7.5 mL/L盐的情况下，54小时内高效实现了高产量（122.41 g/L）和高生产率（3.65 g/L·h）。发酵过程在35°C和pH 6.0下进行，由NaOH控制，接种量为20%体积，搅拌速度为125 rpm。高光学纯浓度的D(-)乳酸的生产与基于NaOH的环保工艺相结合，表明该菌株是生产D(-)乳酸的有前景的菌株。
