Bioprospección de bacterias ácido lácticas productoras de biofloculante aisladas de jugo de caña residual

Abstract

The objective was to isolate bioflocculant-producing lactic acid bacteria (LAB) from residual sugarcane juice. For this reason, sugarcane juice samples were obtained from 15 randomly sampled residual sugarcane stalk samples. The isolation of LAB was then carried out by means of conventional microbiology techniques, using Agar Mayeux, Sandine and Elliker (MSE) culture medium at pH 7.2 and an incubation time of 30°C for 48 hours. Subsequently, pure cultures were made from the characteristic colonies of Leuconostoc mesenteroides (rubbery, viscous, translucent and creamy colonies) for their biochemical identification according to Bergey’s Manual of Bacteriological Determination. The identification and selection of L. mesenteroides subsp. mesenteroides was carried out according to the Kappa coefficient statistical method, with the purpose of using it in the production of dextran (bioflocculant) in an aerated-agitated bioreactor (Aplikon brand). The purity of the dextran was determined using the FT-IR technique, which was compared with the spectrum of pure dextran produced by the strain NRRL P-640. Four strains of Leuconostoc mesenteroides, LM (01-04) were isolated, of which the strain LM03 was identified as L. meenteroides subsp. mesenteroides. The dextran values produced by LM03 were 26.87 g/L at 80 hours (maximum concentration) and 2.61 g/L at 4 hours (minimum concentration). The dextran produced by LM03 is pure according to FT-IR analysis. In conclusion, it was possible to isolate BAL L. mesenteroides subsp. mesenteroides (strain LM03), which had the capacity to produce dextran, which can be used as a bioflocculant with different biotechnological and industrial uses.