新型高效产脲酶菌培养条件优化试验研究

Optimization of Culture Conditions Test for the New Typy of High-efficiency Urease-producing Bacteria

在我国南方湿热气候环境筛选出原状土产脲酶细菌CX21,利用投射电镜对经革兰氏染色原状土细菌形态进行观察,通过比对原状土产脲酶菌的16SrRNA确定其细菌种类。采用紫外诱变技术获得一株新型高效产脲酶菌YB7,通过优化细菌培养环境,提高新型高效产脲酶菌的脲酶活性并筛选出稳定、高效的菌株。结果表明:当pH值为9时突变菌的生长量更高,其酶活也更高;温度对突变菌酶活性具有较大影响,最佳生长温度为25~35℃;提高振荡器转速使得细菌生物量增加,当转速超过130 rpm后,菌液浓度有一定的降低,而转速150 rpm及以上的试验组虽然其细菌生物量有所增加,但细菌活性降低;通过优化突变菌的培养条件,突变菌YB7的酶活性可以达到0.79 ms/min,较原状土产脲酶菌提高了46%。

A urease producing bacterium CX21 whose bacterial species is determined by comparing the 16SrRNA of urease producing bacterium in undisturbed soil and its morphology of urease producing bacterium in undisturbed soil after Gram staining is monitored by Transmission Electron Microscopy(TEM),and it has been screened out in the hot and humid climate of southern China.A new type of high-efficiency urease producing strain YB7 has been obtained by UV mutagenesis.By optimizing the culture environment of the bacteria,the urease activity of the new type of high-efficiency urease producing strain(YB7)has been further improved and the stable and efficient strain has been screened out.The results showed as follows:When the pH value is 9,the growth amount and enzyme activity of mutant bacteria are higher.Temperature has a great influence on the enzyme activity of mutant bacteria,and the optimum growth temperature is 25~35℃.Bacterial biomass increased by increasing the oscillator speed;When the rotational speed exceeds 130 rpm,the concentration of bacterial liquid decreased to a certain extent,while although the bacterial biomass of the experimental group with 150 rpm rational speed and above has increased,yet the bacterial activity has decreased.By optimizing the culture conditions,the enzyme activity of the mutant YB7 has reached 0.79 ms/min,which is 46%higher than that of the original native urease.