Method for preparing gellan gum by fermenting

Abstract

The invention relates to a method for preparing gellan gum by fermenting, which comprises the following steps: inoculating a bevel strain into a shake flask culture medium for culture to prepare a shake flask strain solution; inoculating the shake flask strain solution into a strain culture medium for primary amplification culture to prepare a primary strain solution; and inoculating the primary amplification culture into a fermentation tank for secondary amplification culture to prepare a fermentation broth containing the gellan gum. The culture medium in the fermentation tank comprises the following components: glucose syrup, soy flour, ammonium salt, yeast extract, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, magnesium sulfate, defoaming agent and distilled water. The carbon source in the fermentation tank adopts the glucose syrup to replace white sugar, and the nitrogen source adopts a part of quick-acting inorganic nitrogen source such as ammonium sulfate to supplement the organic nitrogen source appropriately. Due to the components of the culture medium, the types of the carbon source and the nitrogen source in the culture medium are optimized, the strain can grow rapidly, the fermentation steps are simplified, the fermentation time is shortened, the amount of the gellan gum contained in the fermentation broth is improved, and the cost of raw materials is reduced.

Description

technical field [0001] The invention relates to the technical field of microbial fermentation, in particular to a method for preparing gellan gum by fermentation. Background technique [0002] Gellan gum is a kind of hydrophilic colloid developed by the American Keke (KELCO) company. Sphingomonas paucimobilis ) is a fermenting bacteria. After several stages of fermentation and cultivation, the fermented liquid is produced through a series of post-extraction processes. Gellan gum is one of the polysaccharides of the gellan family (Gellan Family). The basic structure of its molecule is a main chain, which is composed of repeated tetrasaccharide units. The monosaccharides involved in the formation are glucose, rhamnose and glucuronide acid, the molar ratio is 2:1:1. Each unit has an O-glyceryl substituent, and the glyceryl is located at the 2-position of the 3-linked glucose residue; in addition, every other unit has an O-acetyl substituent, and the acetyl is at the 6-positio...

AI Technical Summary

Problems solved by technology

First of all, the process is a three-stage fermentation, including primary and secondary seed tank expansion cultivation and three-stage fermenter cultivation. The overall fermentation time is long and there are many processes; secondly, white sugar and soybean protein are used as carbon sources in the large-scale fermentation of this fermentation process. and nitrogen source, the cost of raw materials is high, and it is not conducive to the rapid utilization of carbon and nitrogen sources by bacteria; finally, the excessive ventilation used in this process is mainly caused by unreasonable stirring blades