OPTIMIZATION OF BIOMASS PRODUCTION, LACTIC ACID, AND GASTROINTESTINAL SIMULATION SURVIVAL OF Lactobacillus plantarum BAL-03-ITTG CULTURED IN STIRRED TANK BIOREACTOR

Abstract

Lactobacillus plantarum BAL-03-ITTG is a lactic acid bacterium (BAL) isolated from taberna, a fermented and natural drink, native to Southern Mexico. Due to its fermentation characteristics, this bacterium is potentially useful for the production of biomass and lactic acid in the biotechnology and food industry. However, knowledge of the cultivation conditions is required to maximize its production in a stirred tank system. The objective of this research was to optimize the conditions of agitation, aeration, and Tween-80 concentration in an ez-Control automated bioreactor (Applikon). The response surface methodology (MSR) with a completely randomized factorial design 33 was used at: 100, 200, and 300 rpm agitation levels; 0, 0.25, and 0.5 vvm aeration; and 1, 3, and 5 mL L?1 Tween-80 (v:v). The biomass, lactic acid, and gastrointestinal simulation survival (SSG) data were analyzed with ANOVA and a desirability parameter. The results indicated that cell growth was not significantly affected (p?0.05) within the range of the evaluated factors. Lactic acid production and SSG were significantly influenced (p?0.05) by aeration and Tween-80, respectively. Based on the desirability parameter, the optimal levels were 300 rpm, 0.13 vvm, and 3.06 mL L?1 . Experimental replication of these optimal conditions generated a population density of 7.10?109 UFC mL?1 , lactic acid of 23.8 g L?1 , and SSG of 84.45%. This study provides, for the first time, useful information on the growth conditions of L. plantarum BAL-03-ITTG in a stirred tank bioreactor. The result of this study could be used to obtain the highest yield in the production of lactic acid and biomass, without affecting the integrity of this microorganism.