乳清发酵法制备乙酸

目的]研究一种新的两步厌氧发酵法用于从乳清制备乙酸。方法]以乳清为原料,通过两步发酵法制备出乙酸。在第1步发酵过程中用植物乳杆菌（1.215 8）将乳清中的乳糖发酵成乳酸,在第2步发酵过程中用丙酸杆菌（1.2130）将乳酸发酵成乙酸与丙酸,二者用气相色谱法进行分离,并进行定性与定量分析。结果]在发酵的第1步过程中,乳酸的转化率达到47.47%;在发酵的第2步过程中用气相色谱仪成功地将乙酸与丙酸进行了分离,分离的乙酸转化率达到5.643%;乙酸浓度在1～8 mg/ml范围内时,乙酸进样量与色谱峰面积呈良好的线性关系,方程的相关系数R=0.999 4,回收率为102.7%。结论]利用该方法从乳清制备乙酸,不仅能合理开发利用乳清,而且还能降低乙酸生产成本,具有良好的开发前景。

Preparation of Acetic Acid from Cheese Whey by Fermentation

Objective] The object was to study a new two step anaerobic fermentation method for preparing the acetic acid from the cheese whey.Method] With the cheese whey as the raw material,the acetic acid was prepared out by the two step fermentation method.In the first step of fermentation process,the lactose in the cheese whey was fermented into the lactic acid by using the plant lactobacillus(1.2158);in the second step of fermentation process,the lactic acid were fermented into the acetic acid and propionic acid by using the propionic acid coli(1.2130),both of them were separated by the gas chromatography,and they were made for the qualitative and quantitative analysis.Result] In the first step of fermentation process,the conversion rates of lactic acid was 47.47%.In the second step of fermentation process,the acetic acid and propionic acid were separated by the gas chromatography successfully,the conversion rates of the separated lactic acid reached 5.643%.When the acetic acid was 1~8 mg/ml,there was a good linear relationship between the sampling volume of the acetic acid and the chromatographic peak area,with the equation correlation coefficient R=0.999 4 and the recovery of this method being 102.7%.Conclusion] Using this method for the preparation of acetic acid from the cheese whey not only could develop the cheese whey reasonably,but also could reduce the production cost of producing the acetic acid,which had the good development prospect.