Lactic acid bacteria (Lactococcus lactis NZ9000, Lactococcus lactis MG1363, Lactobacillus plantarum I-UL4 and Lactobacillus johnsonii DSM 20553) have been screened for their ability to produce folate intracellularly and/or extracellularly. L. plantarum I-UL4 was shown to be superior producer of folate compared to other strains. Statistically based experimental designs were used to optimize the medium formulation for the growth of L. plantarum I-UL4 and folate biosynthesis. The optimal values of important factors were determined by response surface methodology (RSM). The effects of carbon sources, nitrogen sources and para-aminobenzoic acid (PABA) concentrations on folate biosynthesis were determined prior to RSM study. The biosynthesis of folate by L. plantarum I-UL4 increased from 36.36 to 60.39 µg/L using the optimized medium formulation compared to the selective Man de Rogosa Sharpe (MRS) medium. Conditions for the optimal growth of L. plantarum I-UL4 and folate biosynthesis as suggested by RSM were as follows: lactose 20 g/L, meat extract 16.57 g/L and PABA 10 µM.
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机译：已经筛选了乳酸菌（乳酸乳球菌NZ9000，乳酸乳球菌MG1363，植物乳杆菌I-UL4和约翰逊乳杆菌DSM 20553）其在细胞内和/或细胞外产生叶酸的能力。与其他菌株相比，植物乳杆菌I-UL4被证明是叶酸的优良生产者。基于统计的实验设计用于优化培养基培养基，以促进植物乳杆菌I-UL4的生长和叶酸的生物合成。重要因素的最佳值由响应面方法（RSM）确定。在进行RSM研究之前，先确定碳源，氮源和对氨基苯甲酸（PABA）浓度对叶酸生物合成的影响。与选择性Man de Rogosa Sharpe（MRS）培养基相比，使用优化的培养基配方，植物乳杆菌I-UL4对叶酸的生物合成从36.36 µg / L增加到60.39 µg / L。 RSM提出了植物乳杆菌I-UL4最佳生长和叶酸生物合成的条件如下：乳糖20 g / L，肉提取物16.57 g / L和PABA 10 µM。
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