同步代谢戊糖、己糖产絮菌的选育

Screen of bioflocculant-product strains on synchronous metabolism pentose and hexose

摘要:

以玉米秸秆为廉价基质,可以有效降低生物絮凝剂合成成本．用1.7％的稀硫酸水解玉米秸秆,获得含有戊糖木糖、己糖葡萄糖的水解液,戊糖很难被微生物代谢．获得能同步代谢戊糖、己糖的产絮菌,是玉米秸秆高效转化为生物絮凝剂的关键．本研究以玉米秸秆水解液为基质选育出产絮菌W4,探讨该菌株同步代谢戊糖、己糖的能力．结果显示,菌株W4经16S rDNA 鉴定为枯草芽孢杆菌Bacills subtilis,其代谢葡萄糖速率(0.27 g·L-1·h-1)大于代谢木糖速率(0.14 g·L-1·h-1),表明菌株W4能够同步代谢木糖、葡萄糖．菌株W4在木糖和葡萄糖培养基中合成生物絮凝剂的絮凝率分别为96％和97％．经红外光谱分析W4生物絮凝剂的主要成分为多糖和蛋白．

Abstract:

Cornstalks, as a kind of cheap substrates, can effectively reduce the cost of bioflocculant’s synthesis. With 1.7％ of dilute sulphuric acid hydrolyzing cornstalks, the hydrolysate containing pentose-xylose and hexose-glucose can be produced. Pentose is difficult to be metabolized by microorganism; obtaining strains which metabolize pentose and hexose synchronously from cornstalks are the key to converse of bioflocculant. This study, based on cornstalks hydrolysate as substrate in screening flocculation Strain W4, explored its ability of synchronous metabolism pentose and hexose. The results revealed that Strain W4 was identified as Bacills subtilis via 16S rDNA. The metabolic rate of glucose (0.27 g·L-1·h-1) by Bacills subtilis exceeded the rate of metabolism of xylose (0.14 g·L-1·h-1), indicating Strain W4 can produce synchronous metabolism of xylose and glucose. The flocculation rate in synthesizing bioflocculant of Strain W4 from xylose and glucose mediums were 96％ and 97％ respectively. The main components of bioflocculant W4 were polysaccharide and protein through the analysis of FTIR (Fourier transform infrared spectroscopy).