Dextran Production from Molasses

Abstract

Teresita O. Macuro, Ma. Lucia C. Sanchez, Ma. Florencia T. Logrono, Dida V. Gatanela, Marilou A. Agravante, Ma. Lourdes T. Escarrilla

The production of dextran is dependent on the amount of glucose in the fermentation broth. Leuconostoc mesenteroides acted on glucose, converting them into glucose-saccharides or glucans. The inversion of sucrose was enhanced by L. mesenteroides microorganisms and the use of hydrochloric acid. During the pH adjustment, considerable amount of sucrose was inverted to glucose and the inversion continued during the fermentation but not all of the sucrose were reduced and used up for dextran production. Inoculated media in the 15o Brix at pH 5 gave the highest yield of dextran and inoculated media in the 20o Brix at pH 5 gave the lowest. The yields of dextran in the inoculated treatments were several times higher than the uninoculated treatments or control.
Dextran content, reducing sugar and sucrose content were monitored up to 48 hours. There was significant correlation between reducing sugar content and dextran production in the inoculated molasses substrate at 15oBrix media both at pH 5. Dextran production also was highest at 24 hrs. In 25oBx at pH 4 inoculated media. Dextran production in all inoculated treatments were very significantly higher than uninoculated treatments.
The microbial activity of L. mesenteroides in the inoculated media was significantly higher that the uninoculated media on all levels of concentrations and pH. Generally, the microbial activity of the inoculated media within the 24-hour fermentation period was high and deteriorated after the 24-hour period. The microbial activity of the control throughout the fermentation period was comparable with the inoculated, however, microbial activity of the uninoculated media was low on all levels of concentrations and pH throughout the fermentation process. The microbial activity of L mesenteroides could be expressed in terms of dextran production, sucrose content and reducing content (glucose) of the fermentation media.
The study also refined the methodology for laboratory-scale extraction of dextran. Refined and absolute alcohol were used to extract dextran. Although the use of refined alcohol is cheaper as an extractant for dextran, absolute alcohol gave higher yield of dextran than refined alcohol.

http://www.sra.gov.ph/abstract/

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