Estudo da viabilidade de produção do biopolímero da bactéria Beijerinckia sp. 7070 via enzimática

Abstract

Biopolymers are microbial polysaccharides used as thickening, gelling and suspending agents. Beijerinckia sp. 7070 produces the biopolymer denominated as clairana. The microbial biopolymers can be produced using purified enzymes (by enzymatic way). The aims of this work were to characterize the biopolymer produced by Beijerinckia sp. 7070 at different fermentation times; to evaluate the possibility to produce this polymer using purified enzymes; to verify if synthesis and the enzymes involved in the synthesis are intra and/or extracellular and if the enzymes remain active in the medium; and to study production, propable chemical composition and reological behaviour of the biopolymer produced using enzymes only (without bacteria action), through cellular inactivation and lyses, and of the biopolymer produced through viable cells. In order to characterize the production at different fermentation times, the samples were cultivated with bacteria in liquid medium. The polymers were recovered, dried and weighed to determine the production and productivity; they then were solubilized in water at 1%, to determine the viscosity and hydrolyzed, for determination of the chemical composition. For production using enzymes only, samples were cultivated with the bacteria, in liquid medium, and subjected to cellular death through cellular inactivation and lyses after 30 and 46 h. The polymers of these samples and the samples produced with viable cells were recovered, at different times, dried and weighed to determine the productions; hydrolyzed, to determine the probable chemical compositions and solubilized in water at 6%, to evaluate the reological behaviour. In the characterization of the polymers at different times, the highest total biopolymer productions found were in 30 and 72 h, the highest productivity was in 48 h and the highest viscosity was presented by the polymer in 72 h. All polymers showed the same chemical composition, but with different proportions. The results of the production using enzymes only suggest that it is possible to produce the clairana biopolymer by enzymatic way. It suggests yet that intra and extracellular enzymes are involved, they remain active in the medium and begin to act before 30 h of fermentation and the process through cellular lyses is more effective than through cellular inactivation. With regarding to the chemical composition, all samples presented the same components at different proportions and, regarding the reological behaviour, the highest viscosity found, in general, were of the biopolymers produced with lysed cells being the highest of the biopolymer produced with lysed cells in 46 h removed in 54 h.