Avaliação da produção de exopolissacarideo insoluvel por duas linhagens de Agrobacterium sp

AUTOR(ES)

Marcia Portilho

DATA DE PUBLICAÇÃO

2002

RESUMO

Some bacteria of Agrobacterium genus isolated from soil samples and not pathogenic produce two extracellular polysaccharides: an acid and soluble succinoglycan and curdlan gum, an insoluble and neutral polymer. The last one, which received the approval of the FDA - Food and Drug Administration - USA - in 1996, is usually used in food industry because of its property of a fmn, resilient and excellent gel. The present work was carried on in order to elaborate a medium to obtain a inoculum and evaluate aspects related to the production of an insoluble polysaccharide in two strains of Agrobacterium sp (ATCC 31749 and IFO 13140). It was used an yeast extract, commercially available as a medium, in order to create a microbial inoculum, defined as a nitrogen and salts sources. Tests were made using glucose, sucrose and sugar cane molasses in different concentrations as carbon source. The medium elaborated with yeast extract and sucrose presented the best results related to growth in both strains. The inoculums produced by that culture were suitable to the production of insoluble polysaccharides in the medium proposed in the literature. The samples of insoluble polysaccharide obtained from the evaluated strains were compared to a commercial sample of insoluble polysaccharide (curdlan) through tests of solubility, high-pressure liquid chromatography, infrared spectrometry and ability to produce gel. Both strains produced a polysaccharide whose features were very similar to the commercial curdlan. Maize glucose, cassava glucose and maize maltose were used as a fermentation medium to the production of the insoluble polysaccharide as a substitute of carbon source in the medium proposed in the literature. Both strains produced the polysaccharide and the results were the sameor higher than the literature (50,00%). The strain ATCC 31749 presented the best production using maize maltose (productivity of 84,68%) and strain IFO 13140produced better through maize glucose (productivity of 50,00%)

ASSUNTO(S)

agrobacterium biopolimeros polissacarideos microbianos

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