Biotechnological production of surfactante of Bacillus subtilis in agro-industrial residue, characterization and applications. / Produção biotecnologica de surfatante de Bacillus subtilis em residuo agroindustrial, caracterização e aplicações.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Biosurfactants are amphypatic compounds from biologycal source showing both hydrophilic and lipophilic groups. Due to this feature, the biosurfactants acts decreasing the surface and interfacial tension of a liquid. The byproducts of agricola and industrial processing are an underexplored new sources to the production of biotechnological interesting compounds. The cassava industrialization yields c.a. 240.000L of residue by month. This residue, cassava wastewater (manipueira), is highly toxic (due to the presence of cianogenic glycosides) and poluent (due to high concentrations of organic matter, that may reach 100 gDQO/L). The possibility of the utilization of manipueira as substract for microorganism growth and the interest in the production of biotecnologically important aducts, encourage us to investigate the biosurfactants production by Bacillus subtilis LB5a strain. After the growing conditions optimizations, 2,5 g/L of surfactant was obtained in 36 hours. The biosurfactant have reduced the surface tension of the medium from 47,74 mN/m to 25,96 mN/m, CMD-1 of 26,19 and CMD-2 of 29,47 mN/m, with interfacial tension against hexadecane of 0,76 mN/m and CMC of 10 mg.L-1. The extract show stability with respect to high salt concentration, high temperature, wide range of pH (6-12) and to several concentrations of diferent cysteine proteases. The aminoacids analysis of purified product, revealed the presence of glutamic acid, aspartic acid, valine and leucine at a 1:1:1:4 ratio, characterizing the product as a lipopetide. Mass spectrometry analysis confirmed the presence of a lipopeptide homologous serie with variations in the hydrocarbon chain lenght, known as surfactin. Furthemore, was verified the predominance of the 1036 g.Mol-1 molecular mass homologous. The biosurfactant from LB5a strain was able to produce stable emulsions in oils, hydrocarbons and fuels, bioremediation and Microbial Enhanced Oil Recovery (MEOR), potential were observed by the remotion of crude oil from contaminated sand. The surfactin also showed antibacterial activity agains gram positive and negative bacterias and showed antiproliferative activity agains human tumoral cells. The results described herein give important data reflecting the surfactant potential of the surfactin and its applications. Moreover, they reveal the manipueira as an excellent substrate to the biosurfactant production by the studied strain. The utilization of an industrial residue as substrate allows a strong cost reduction to the sufactant production and consists a potentially alternative to the treatment of this effluent.

ASSUNTO(S)

tensão superficial agentes antibacterianos biosurfactants surface tension biosurfactantes bacillus subtillus bacillus subtilis antibacterial agents

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