Abstract:

Nowadays, genetic engineering make it possible for maize with insect resistance by transferring Bt gene. Satety and effects of  Bt transgenic maize in its influence on the composite microbial system of SFC\|2 during the fermentation process was studied. The change of pH, the speed of cellulose decomposing, the qualitative and quantitative analysis of decomposing outcome (GCMS), the content of Bt toxin were surveyed entirely. DGGE (degeneration grad gel electrophoresis) method was applied to provide a test in molecule level microorganism genetic material in the process of fermentation. The effect of SFC\|2 on straw fermentation was described by comparing the difference between the transgenic corn and non\|transgenic corn. The results showed that the lactobacillus community SFC\|2 was inoculated into the corn straw and its fermentation effects were good. The smell of fragrance was also good. The quality of material was loose and the luster was bright. In the initial period, pH value dropped quickly and reached the minimum value at the 7th day, then increased slowly. There is no great significant pH value difference between transgenic and non\|transgenic corn. Soluble sugar content showed the same trend with pH value, which reached the lowest value in the 13th day. There was also no great significant difference. Except the crude protein content increased a little, the content of crude fat and ash did not change during the fermentation time. The differences between these characteristics were also not significant. The measurement of Bt toxin content showed that the 2 transgenic corns descended significantly in the 7th day. Bt toxin content reduced gradually during the whole fermentation period. GCMS showed that there were no great differances in these 4 corns, such as the content of ethanol, acetic acid, lactic acid and glycerin. Our results could confirm that Bt transgenic maize has no positive effect on microorganism, but offer the means to evaluate the potential non\|target effects of transgenic crops. Hence, this study has provided preliminary evidence for the rational use and safety evaluation of Bt transgenic maize.

Key words: Bt transgenic corn, microbial community, straw fermentation

摘要：

当前，利用生物基因工程技术将外源抗虫基因导入玉米, 使玉米自身产生抗虫蛋白而达到抗虫目的成为可能。为了明确转基因玉米携带Bt蛋白参与微生物发酵的安全性与效应,利用乳酸菌复合系SFC\|2对转Bt基因及非转基因玉米秸秆进行接种，通过对发酵过程的pH变化、纤维素降解率、分解产物定性定量分析、Bt毒蛋白含量进行全程检测，并采用DGGE（变性梯度凝胶电泳）方法在分子水平上对发酵过程中的微生物遗传物质进行监测。结果表明，乳酸菌复合系SFC\|2对转基因与非转基因玉米进行接种并发酵后，4种玉米秸秆的气味具有甜酸香味、色泽好、质地松散，且pH符合发酵饲料的要求；发酵体系中pH变化情况没有显著差异；可溶性糖含量变化无显著差异；气质联机分析表明，转Bt基因和非转基因玉米秸秆发酵过程中发酵产物种类无差异，乙醇、乙酸、乳酸及甘油产生量无显著差异；转Bt基因玉米在发酵过程中秸秆的毒蛋白含量呈现不断下降的趋势。本研究结果为转 Bt 基因玉米的合理利用和安全性评价提供了初步依据。

关键词: 转Bt基因玉米；微生物菌系；秸秆发酵