Method of using lignocellulose for preparing DHA

Abstract

The invention provides a process for producing DHA with lignocellulosic agricultural and forestry waste as a raw material in order to solve problems of industrial production of DHA in the prior art. The process includes the steps of pretreatment, saccharification, fermentation of schizochytrium limacinum, extraction of DHA and the like. The process adopts a combination of lignocellulosic biosaccharification and high-density schizochytrium limacinum fermentation; by adopting lignocellulosic biomass as the raw material, on the one hand, the production cost of DHA is significantly reduced; on theother hand, the problem of comprehensive utilization of the agricultural and forestry waste is also solved. In the process, a lignocellulose saccharification stage culture medium and a fermentation medium can be recycled so that water can be significantly saved, and the use of chemicals is reduced. In addition, the cellulose saccharification efficiency is 80-90%, the biomass of schizochytrium limacinum can reach 15-80g / L, and the production of DHA is 5-25g / L. Compared with the prior art, the process has the advantage that the production and yield of DHA are higher.

Description

technical field [0001] The invention relates to the field of microbial fermentation engineering, in particular to a method for preparing docosahexaenoic acid from lignocellulose raw materials. Background technique [0002] Docosahexaenoic Acid (DHA) is an essential polyunsaturated fatty acid that must be supplemented from the diet. DHA is an important structural lipid component of the central nervous system and retina. It has the functions of strengthening the brain, improving memory and vision, especially promoting the development and growth of brain cells in fetuses and infants, improving the memory of adolescents, and preventing and treating senile dementia. Traditionally, DHA is mainly derived from deep-sea fish oil, but due to the great impact of overfishing, environmental pollution, seasonal changes, etc., it is gradually replaced by microbial fermentation production. At the present stage, the industrial DHA production is mainly realized through the fermentation of Au...

AI Technical Summary

Problems solved by technology

The strategy of using fungal-derived enzyme preparations has insufficient efficiency and cost, mainly because the cellulase preparation needs to be prepared by microbial fermentation in a separate reactor, and the preparation process is different from the cellulose hydrolysis conditions, and the production steps are cumbersome Complexity, significant increase in manpower and material requirements and equipment investment costs make the saccharification process of lignocellulose uncompetitive in the market, so it is difficult to achieve large-scale industrial application of saccharification and DHA preparation technology based on fungal cellulase preparations

Invention patent 2015108721949 provides a method of directly using bagasse hydrolyzate to ferment Schizochytrium fungus. The substrate bagasse is hydrolyzed with dilute acid to obtain hydrolyzate instead of enzymatic hydrolysis, which has the potential risk of environmental pollution; in addition, due to Substances such as furfural in the hydrolyzate have a strong growth-inhibiting effect, requiring special strains of Schizochytrium to grow directly in the hydrolyzate, and the biomass and oil or DHA output of the bacteria are low

However, since the activity and stability of exogenously added proteins will decrease with the progress of the saccharification process, the consumption of enzymes requires an increase in the amount or frequency of enzyme addition

In addition, these non-cellulosomal proteins are added to the saccharification system as free enzymes, which cannot interact with cellulosomes, and will significantly reduce the synergistic effect with other enzymes in the system, inevitably resulting in additional enzymes that are greater than the demand, resulting in The high cost of enzyme preparations

Not only that, this saccharification strategy that relies on the addition of exogenous free enzymes has complex processes, high equipment requirements, and conversion efficiency that cannot meet the requirements of industrial production.

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