Abiotic stress approaches for enhancing cellulose and chitin production in Chlorella vulgaris

Several lines of evidence point to the presence of both, cellulose and chitin as structural constituents of the Chlorella vulgaris cell wall. These biopolymers are favourable building blocks for many sustainable industrial applications for instance as biocompatible and biodegradable packaging materials with useful mechanical and barrier properties. However, no feasible strategy is yet available for selectively enhancing the productivity of these biopolymers for future commercial applications. Here, we present some simple and cost-effective abiotic stress approaches to remarkably increase the cell wall thickness in C. vulgaris thereby significantly improving the biopolymer productivity by a factor of three. Using a double staining approach, we reveal for the first time the structural organization of chitin and cellulose in alternating layers under specific stress conditions, presumably contributing to a higher cell wall stability. Our results may help to foster innovative processes using chitin and cellulose composite materials from a photosynthetic organism.