Rapid adaptation for fibre degradation by changes in plasmid stoichiometry within Lactobacillus plantarum at the synthetic community level

Abstract

The multi-enzyme cellulosome complex can mediate the valorization of lignocellulosic biomass into soluble sugars that can serve in the production of biofuels and valuable products. A potent bacterial chassis for the production of active cellulosomes displayed on the cell surface is the bacterium Lactobacillus plantarum, a lactic acid bacterium used in many applications. Here, we developed a methodological pipeline to produce improved designer cellulosomes, using a cell-consortium approach, whereby the different components self-assemble on the surface of L. plantarum. The pipeline served as a vehicle to select and optimize the secretion efficiency of potent designer cellulosome enzyme components, to screen for the most efficient enzymatic combinations and to assess attempts to grow the engineered bacterial cells on wheat straw as a sole carbon source. Using this strategy, we were able to improve the secretion efficiency of the selected enzymes and to secrete a fully functional high-molecular-weight scaffoldin component. The adaptive laboratory process served to increase significantly the enzymatic activity of the most efficient cell consortium. Internal plasmid rearrangement towards a higher enzymatic performance attested for the suitability of the approach, which suggests that this strategy represents an efficient way for microbes to adapt to changing conditions.

Current Progress in Production of Building-Block Organic Acids by Consolidated Bioprocessing of Lignocellulose

“…Of note, the design of engineered LAB consortia, in which each strain expresses a single heterologous enzyme or protein, led to display of mini-cellulosomes consisting of up to six enzymatic components (of four different types, i.e., two cellulases and two xylanases from Clostridium papyrosolvens) on the surface of L. plantarum [46]. This engineered L. plantarum consortium showed improved hydrolysis of wheat straw, yet the amount and/or type of sugars released was insufficient/unsuitable to support L. plantarum growth [46,86]. As regards expression of heterologous (hemi)cellulases, Bacillus sp.…”

Directed evolution of microbial communities

“…Given the growing appreciation of the many important roles that groups of individuals (populations, communities, and ecosystems) play in natural and technological processes (13,49,57,63,69,72,84,97,110,120) , it has been proposed that artificial selection may be also applied above the level of the organism to engineer community-level functions from the top-down (25, 72, 104) ( Fig. 1A).…”