Efficient endo-11-1,3-glucanase expression in Pichia pastoris for co-culture with Agrobacterium sp. for direct curdlan oligosaccharide production

The production of curdlan oligosaccharides, a multifunctional and valuable carbohydrate, by hydrolyzing polysaccharides is of great interest. The endo-11-1,3-glucanase derived from Trichoderma harzianum was expressed in Pichia pastoris with three commonly used promoters (AOX1, GAP and FLD1). The purified recombinant endo-11-1,3-glucanase expressed by Pichia pastoris with GAP promoter displayed high specific activity at pH 5.5 and 50 C-circle. Thereafter, a co-culture system of Pichia pastoris GS115 (GAP promoter) and Agrobacterium sp. was constructed in which Agrobacterium sp.-metabolized curdlan can be directly hydrolyzed by Pichia pastoris- secreted endo-11-1,3-glucanase to produce functional curdlan oligosaccharides. The co-culture conditions were optimized and the process was carried out in a 7-L bioreactor. The maximum yield of curdlan oligosaccharides reached 18.77 g/L with 3-10 degrees of polymerization. This study presents a novel and easy curdlan oligosaccharide production strategy that can replace traditional sophisticated production procedures and could potentially be implemented for production of other oligosaccharides. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study involved the production of curdlan oligosaccharides by expressing endo-11-1,3-glucanase in Pichia pastoris and constructing a co-culture system. The optimized conditions in a 7-L bioreactor led to a maximum yield of 18.77 g/L of curdlan oligosaccharides with 3-10 degrees of polymerization, presenting a novel strategy for oligosaccharide production.