P51: Improvement of lactic acid production of Sporolactobacillus sp Vini6 and selection of carbon sources

Lactic acid is used as preservative in the food, pharmaceutical and for polymerization to biodegradable poly lactic acid. Current industrial lactic acid fermentations are performed with lactic acid bacteria and several strategies have been applied in order to improve the productivity of these bacteria.The screening was performed on UV-mutagenized populations through three rounds of cell sorting in which only the viable cells. Sporolactobacillus sp Vini6 previously mutated by UV-mutagenized were submitted to genome shuffling, according Zheng et al (2010). After three rounds, new microorganisms were obtained, which were evaluated towards (D)-acid lactic production. This production also was evaluated in the different substrates as sole carbon source 100 g/L in GYP medium, added calcium carbonate at 150 rpm for 48 h. Lactic acid concentrations were determined by a high performance liquid chromatography system equipped with a UV detector at 210 nm.  The results showed that lactic acid production was improved in the Sporolactobacillussp Vini6 mutant obtained on the second round of UV-mutagenesis compared to the parental strains, while genome shuffling does not improve the acid lactic production. The carbon sources that induced the highest acid lactic production were sucrose, glucose and sugarcane juice. The mutagenesis was able to improve acid lactic production and the sucrose was more effective on induction lactic acid production. 

 ZHENG, H.; GONG J.; CHEN, T.; CHEN, X.; ZHAO, X.; Strain improvement of Sporolactobacillus inulinus ATCC15538 for acid tolerance and production of D-lactic acid by genome shuffling. Appl Microbiol Biotechnol. v. 85. p. 1541–1549, 2010.