Study On Trehalose Production From Starch By Enzymatic Method

Trehalose is a non-reducing disaccharide that is widespread in nature. It is able to protect the integrity of the cell against a variety of environmental injuries and nutritional limitations. This paper is mainly concerned with the studies on trehalose production from starch by enzymatic method, which include the researches on technical flow and production conditions and processing optimization.Based on Micrococcus roseus, we screened and got the QS412 strain that was treated with ultraviolet inducement. Composition and proportion of the medium was investigated. And we obtained the results: glucose 2.0%, yeast extract powder 2.0%, peptone 1.0%, K2HPO4-3H2O 0.1%, MgSO4-7H2O 0.05%. Fermentation conditions include inoculation 15%, medium volume 50mL/250mL, initial pH 7.5-8.5, culture temperature 30 C, culture time 4d. In 20L fermentation tank, the fermentation period has been reduced to 56h; the maximal biomass is about 100mg/mL, and the dried weight is 27mg/mL, which is 40% higher than that of flask culture.Maltooligosyl trehalose synthase (MTSase) and Maltooligosyl trehalose trehalohydrolase (MTHase) are both intercellular enzymes, so celldisruption is important to release them. Toluene disruption is chosen as our experiment method. The optimal disruption conditions were as follows: toluene dosage 5%, treatment time 0.5h, treatment temperature 35 C.Trehalose was produced by the role of two enzymes MTSase and MTHase. The conditions of enzyme reaction on liquefied starch were also studied. We can get trehalose 52.76mg/mL and conversion rate of liquefied starch 52.7% under the optimal conditions of buffer concentration lOOmmol/L, pH 8.0, reaction temperature 30 C, reaction time 24h and substrate concentration 20%.The separation and purification of trehalose was also researched. The maltose that existed in enzymatic reaction liquid was hydrolyzed into glucose by HCl, while the trehalose remained 86.9%. And then glucose and trehalose were isolated by successive displacement with water and 5% ethanol through a charcoal column. Charcoal columns also have a large separation capacity for sugar.