蔗糖、麥芽糖及甘露糖對Klebsiella oxytoca CF154所產胞外黏性物質之產量及其組成與特性之影響

Abstract

Effects of the replacement sucrose with either maltose or mannose in mucous screening basal medium (MSBB) on the yield, sugar conversion, monosaccharide composition, and their relative viscosity of lyophilized extracellular mucilage powder (LEM) from Klebsiella oxytoca CF154 culture were investigated. The yield of LEM made from maltose-MSBB was the highest (1.75 g/l), and followed by sucrose-MSBB (0.98 g/l) and mannose-MSBB (0.53 g/l). The sugar conversions of LEM prepared from three sugar source of MSBB were found follow the order of maltose (35.01%) ＞ sucrose (33.17%) ＞ mannose (11.89%). 0.2% LEM solutions from three media showed that the relative viscosity (RV) is stable over a pH range from 4 to 9, but decreased as the temperature increased from 10 to 80 ℃, and the higher NaCl concentration (0-5%) in LEM solutions is the lower RV of LEM solutions. The dominant fraction relating viscosity of 0.2% LEM from three media was eluted by gel permeation chromatography, respectively. After HPLC analysis, the major sugars in this dominant fraction contain mannose, galactose, glucose, and arabinose in three LEM samples. But the contents of sugar compositions in LEM differ among three LEM samples. Accordingly, the major biosynthesis pathway of LEM from sucrose, mannose, or maltose might be the same by K. oxytoca CF154 using sucrose, mannose, or maltose as the sole sugar source.