以江蓠琼脂为原料制备生化琼脂

将江蓠琼脂粉与5种生化琼脂的理化指标进行对比，研究了羧甲基修饰制备生化琼脂的技术，利用羧甲基化反应降低江蓠琼脂的融化温度并提高透明度. 结果表明，江蓠琼脂与商品生化琼脂的主要区别在于融化温度高且透明度低. 反应的优化参数为氯乙酸添加量0.15 g/g，反应温度60℃. 对反应液重复利用，可节省70.8% Na2SO4和57.0% NaOH. 中试所制羧甲基琼脂的理化指标与小试结果一致，符合理化质量标准，比国内外生化琼脂的凝胶强度和透明度高，与Sigma A6686和028990生化琼脂无显著差异. 日产1 t羧甲基化江蓠琼脂粉的原料成本为12.07万元.

Preparation of Biochemical Agar Using Gracilaria Agar as Raw Material

The key physicochemical properties of the domestic gracilaria agar and five kinds of commercial biochemical agars were investigated and compared, and the preparation technology of the biochemical agar was further studied by using the carboxymethyl modification method to decrease the melting temperature and promote the transparency of gracilaria agar and further optimized to produce biochemical agar. The results revealed that the gracilaria agar showed related higher melting temperature and lower transparency than these biochemical agars, which were the primary distinctive physicochemical properties between the gracilaria agar and these biochemical agars. The optimized preparation parameters were as follows: the amount of chloroacetic acid was 0.15 g/g and the reaction temperature was 60℃. Under these optimal conditions, 70.8% of Na2SO4 and 57% of NaOH can be reduced respectively through the reutilization of the reaction liquid. The physicochemical properties of synthetic carboxymethyl agar produced by the pilot-scale tests were in accordance with those obtained in the small-scale tests. Meanwhile, the synthetic carboxymethyl agar was consistent with the domestic and international quality standards of the biochemical agars. Moreover, the synthetic carboxymethyl agar possessed a better gel strength and transparency than those commercial biochemical agars. In addition, there is no significant difference between the carboxymethyl agar prepared by the pilot-scale tests and the commercial biochemical agars such as Sigma A6686 and 028990 in the microbial growth tests. The raw materials cost of carboxymethyl agar (1 t/d) is ￥120700.