Method for preparing oleaginous yeast fermentation medium from dewatered sludge and its application

Abstract

The invention relates to a method for preparing an oil-producing yeast fermentation medium from dehydrated sludge and an application thereof. The method comprise the following steps: (1) using dehydrated sludge produced by a sewage treatment plant as a raw material, after dilution to medium concentration, obtain clean liquid by using hot alkali pretreatment; (2) inoculating the sludge in a concentration tank of the same sludge treatment plant to the clear liquid, and carrying out anaerobic fermentation at room temperature to obtain clear liquid; (3) removing the humic acid, protein and ammonianitrogen in the obtained solution by using a regulating method combing coagulation, acid extraction and guano precipitation to obtain and the solution with high C / N and high volatile fatty acid; (4)after sterilization, using the obtained solution as the oil-producing yeast fermentation medium; (5) culturing oil-producing yeast by using batch culture mode; (6) extracting microbial oil from the cultured yeast cells. The method achieves the resource utilization and energy utilization of the dehydrated sludge, and has certain environmental and economic benefits.

Description

technical field [0001] The invention relates to a method for preparing oleaginous yeast fermentation medium from dewatered sludge and an application thereof, which belongs to the field of sludge resource treatment and also relates to the field of microbial oil synthesis. Background technique [0002] Volatile fatty acids are carbon sources that can be directly utilized by yeast. Compared with the traditional carbon source glucose, the conversion pathway of volatile fatty acids to oil is shorter and the theoretical conversion efficiency is higher. Previous studies have used the volatile fatty acid solution obtained from anaerobic fermentation of excess sludge (water content 99%) as a carbon source to cultivate oleaginous yeast, and obtained microbial oil that can be used for the preparation of biodiesel. However, the excess sludge has a high moisture content and is not easy to transport and store. The dewatered sludge obtained by the sewage treatment plant after deep dehydra...

AI Technical Summary

Problems solved by technology

The pretreatment method used requires the use of physical and chemical methods such as higher temperature or strong acid and strong alkali. These operations will produce some substances that are toxic or inhibitory to microorganisms.

In addition, the carbon-nitrogen ratio in the fermentation broth after anaerobic fermentation of dewatered sludge is very low, which cannot meet the normal growth needs of oleaginous yeast

Therefore, for high-concentration dewatered sludge, the acid-producing liquid obtained after pretreatment and anaerobic fermentation cannot be directly used as a medium for cultivating oleaginous yeast

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