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摘要
The effect of the variables pantothenic acid, yeast extract and sodiumchloride, as well as the cell permeabilization technique, were investigated on the formation of levan, ethanol, sorbitol and biomass of Zymomonas mobilis, using a 24-1 fraction factorial design. Cell growth was determined by turbidimetry at 605 nm, relating it to a biomass with a dry weight calibration curve. Reducing sugars were quantified according to Somogyi and Nelson. Total sugars were quantified by the phenol-sulfuric acid method, sorbitol by HPLC and ethanol. The levan produced was precipitated by the addition of absolute ethanol and quantified in fructose units. In levan biosynthesis, the variable that had the largest contribution was cell condition. The results suggested that the factors that most affected biomass and ethanol formation were sodium chloride concentration and cell condition that affected negatively on production. For sorbitol, the variable that had a significant effect was permeabilization, which decreased its synthesis. Studies to amplify the range of established factors would be important. A influ那ncia das vari芍veis: 芍cido pantot那nico, extrato de levedura, cloreto de s車dio, e a t谷cnica de permeabiliza o celular foram investigadas na forma o de levana, sorbitol, etanol e biomassa de Zymomonas mobilis utilizando um delineamento estat赤stico fatorial fracionado 24-1. A biomassa foi determinada por turbidimetria, Os a 迆cares redutores foram quantificados por Somogy e Nelson, a 迆cartotal por Fenol Sulf迆rico, sorbitol por HPLC e etanol por micro-destila o. A levana produzida foi precipitada com etanol absoluto e determinada como unidade de frutose. Na bioss赤ntese de levana, a vari芍vel que mais contribuiu foi a condi o celular. Os resultadossugerem que, para a forma o da biomassa e etanol, os fatores que mais interferiram foram a concentra o de cloreto de s車dio e a condi o celular que influencia negativamente a produ o. Para o sorbitol, a vari芍vel que teve efeito significativo foi a permeabiliza o celular que atuou diminuindo a sua s赤ntese. Estudos que ampliam a faixa de varia o dos fatores estabelecidos s o interessantes.
- 出版日期2010
