CAJ | 학술논문

通过高岭土悬浊法考察微生物絮凝剂产生菌的絮凝活性，采用平板划线法从土壤样品中分离得到一株具有较高絮凝活性的菌株C412。根据菌落形态观察、生理生化实验和16S rDNA序列相似性比对，判定菌株C412为解淀粉芽孢杆菌。通过单因素法优化培养基，发现可溶性淀粉为最佳碳源；硫酸铵和牛肉膏复合为最佳氮源；添加适量的Na+和Mg2+有益菌株生长和絮凝活性提高。优化后的培养基组成为：15 g/L可溶性淀粉、1 g/L牛肉膏、3 g/L硫酸铵、1 g/L NaCl、0.05 g/L MgSO4·6H2O、5 g/L K2HPO4、2 g/L KH2PO4(pH=7)。菌株C412在此培养基中生长17 h后，菌体浓度( OD600)达到最大(3.18)，其最大絮凝活性可达95.53%。从发酵上清液中提取的生物絮凝剂耐热区间(4~60℃)和体系工作pH范围(4~13)较为广泛。
통과고령토현탁법고찰미생물서응제산생균적서응활성，채용평판화선법종토양양품중분리득도일주구유교고서응활성적균주C412。근거균락형태관찰、생리생화실험화16S rDNA서렬상사성비대，판정균주C412위해정분아포간균。통과단인소법우화배양기，발현가용성정분위최가탄원；류산안화우육고복합위최가담원；첨가괄량적Na+화Mg2+유익균주생장화서응활성제고。우화후적배양기조성위：15 g/L가용성정분、1 g/L우육고、3 g/L류산안、1 g/L NaCl、0.05 g/L MgSO4·6H2O、5 g/L K2HPO4、2 g/L KH2PO4(pH=7)。균주C412재차배양기중생장17 h후，균체농도( OD600)체도최대(3.18)，기최대서응활성가체95.53%。종발효상청액중제취적생물서응제내열구간(4~60℃)화체계공작pH범위(4~13)교위엄범。
In this study, a new bioflocculant-producing strain C412 was isolated from soil sam-ples. The isolated strain was derived amyloliquefaciens bacillus via characteristics of morphology as well as biochemical and physiological analyses and the comparison of 16 S rDNA sequencing. 16 S rD-NA nucleotide sequencing analyses revealed that the strain C412 was closely related with the amyloliquefaciens bacillus with 99% similarity. Culture conditions optimization for strain C412 , in-cluding culture time, carbon sources, nitrogen sources and metal ions on bioflocculant production and biomass was investigated by single factor test. The best carbon and nitrogen sources for producing flocculation were soluble starch and beef extract, respectively. The fermentation kinetics analysis showed that strain C412 reached the highest values of biomass production and flocculating activity (95. 53%) in 17 h. These results indicated that the optimal medium for bioflocculant production was 15 g/L soluble starch, 1 g/L beef extract, 3 g/L ( NH4 ) 2 SO4 , 1 g/L NaCl, 5 g/L K2 HPO4 , 2 g/L KH2PO4, 0. 05 g/L MgSO4·6H2O (pH=7). Infrared spectrophotometry analysis indicated that this bioflocculant contained hydroxyl, amino, carbonyl, and methoxyl groups in its structure and these <br> groups were beneficial for flocculation process. This study indicated this bioflocculant was applicable under wide range pH condition between 4 and 13 and had heat resisting property between 4 and 60℃). Further study on its flocculation properties and culture scaling-up process are in progress with the purpose of enhancing the yield of bioflocculant and realize its industrial utilization.