Escherichia coli engineering bacterium and method for whole-cell catalytic production of steviol

Abstract

The invention discloses a recombinant escherichia coli engineering bacterium pSE-sbgl-spbgl1 and a method for whole-cell catalytic production of steviol by the recombinant escherichia coli engineeringbacterium pSE-sbgl-spbgl1. The strain co-expresses double beta-glucosidase SPBGL1 and SBGL in a polycistron form, and with a stevia rebaudiana crude extract as a substrate, stevioside and rubusosidein the stevia rebaudiana crude extract are catalyzed to be hydrolyzed to produce steviol by using the whole-cell catalysis method. The engineering bacterium pSE-sbgl-spbgl1 is used for catalyzing stevioside to produce steviol in a whole-cell mode, and the method has the advantages of being high in conversion rate, high in yield, single in product, low in energy consumption, short in consumed time,easy to operate, high in industrialization potential and the like.

Description

technical field

[0001] The invention relates to the field of bioengineering technology and biosynthesis of natural compounds, in particular to a strain of Escherichia coli engineering bacteria and a method for producing steviol by catalyzing whole cells thereof. Background technique

[0002] Stevia is a perennial herb native to Paraguay, South America (LEWIS W H. Early Uses of Stevia rebaudiana (Asteraceae) Leaves as a Sweetener in Paraguay [J]. Economic Botany, 1992, 46 (3): 336-7), It is also planted in Southwest my country, one of which is commonly known as sweet tea, which exists in large quantities in Guangxi (LIU Z, SCHWIMER J, LIU D, et al.Gallic acid is partially responsible for the antiangiogenic activities of Rubus leaf extract[J].Phytother Res , 2006, 20(9):806-13). Stevioside is a low-calorie sweetener extracted from stevia leaves. According to research, its sweetness is 200-350 times that of sucrose, but its calories are only 1 / 300 of that of sucrose (ORGANIZATIO...

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