一株微生物絮凝剂产生菌的培养基优化研究

An experimental research on culture medium optimization of a flocculant-producing strain

利用单因子实验和部分因子实验对实验室保藏的产絮凝剂菌种C3的培养基进行优化,以提高C3菌所产生的微生物絮凝剂MBFC3的絮凝效果。实验结果表明,C3菌产MBFC3的最适培养基为:蔗糖1.0g,(NH4)2SO40.24g,FeSO40.10g,KH2PO40.40g,MgSO40.01g,NaCl0.02g,蒸馏水100mL,pH值自然。在此培养条件下,C3菌所产生的微生物絮凝剂MBFC3对高岭土悬浮液的絮凝率可达到99.1%。实验中还发现,培养基中(NH4)2SO4和NaCl的用量是影响MBFC3絮凝效果的显著因素。

This paper is aimed at presenting our experimental research on how to optimize the culture medium of C3 so as to improve the flocculating activities of MBFC3.A flocculant-producing strain designated as bacillus, The bacillus can be used to produce highly effective bioflocculants known as MBFC3. The strain enjoys great value for research work and therefore it is highly promising in future application not only for its highly flocculating activity against kaoling clay suspension and short cultivation time, just in an about 16 - hour period. To optimize the culture medium of C3, we have been engaged＇in the single factorial design and fractional factorial design in our experiments. First of all, we have done single factorial design to probe into the optimum carbon source and nitrogen source to search for the desirable culture media. The results of our experiments show that sugar cane and ammonia sulfate are likely to be the optimum carbon source and nitrogen source. With these substances as desirable sources, the flocculating activity against kaoling clay suspension can be managed to get to 95.3 %. Then, we have proceeded with fractional factorial design to test which kind of substance in the culture medium is the best factor that can bring about the remarkable influence. The results of our experiments indicate that ammonia sulfate and sodium chloride can produce prominent influence on the flocculating activity of MBFC3 with increased dosage being able to improve the flocculating activity. And, finally, with other substances of the culture medium keeping on lower dosage, experiments are done to determine the optimum dosage of ammonia sulfate and sodium chloride. From all these experiments, the optimum culture medium of C3 has been obtained, that is, cane sugar 1,0 g, ammonia sulfate 0.24 g, ferrous sulfate 0.10 g, potassium dihydrogen phosphate 0.40 g, magnesium sulfate 0.01 g, sodium chloride 0.02 g, distilled water i00 mL, pH natural. In this culture medium, the flocculating activity of. MBFC3 reaches to 99.1%. Though the above results are all encouraging, litde has so far been done in the research on the effect of inorganic salts on microbes producing bioflocculant, it is therefore necessary to go on with our research in this field to improve the flocculating activity of flocculant-producing strain.