Scleroglucan production by Sclerotium rolfsii ATCC 201126 from amylaceous and sugarcane molasses-based media

VALDEZ AL; BABOT JD; JOCHEN SCHMID; DELGADO OD; FARIÑA JI

Straubing

Simposio; X European Symposium on BioPolymers 2019; 2019

Wissenschafstzentrum Straubing TUM & CARMEN

Biotechnology tries solving the growing demand on biodegradable polymers of low costs, high quality and viscosifying properties. The large-scale production of microbial exopolysaccharides (EPSs) by controlled fermentation is a promising example of biobased polymers, with world markets representing several hundred million dollars annually. Scleroglucan (SC) is one of these microbial EPS, produced mainly by fungi of the genus Sclerotium, under optimized and standardized cultivation conditions. Its excellent properties makes it especially attractive for various industrial applications ranging from assisted oil recovery to the cosmetic industry. To further optimize its production and economy, in this work, nine alternative low-cost C- and twelve N-sources were comparatively assessed. When comparing conventional sucrose-based Production Medium PM (8.41g C/L + NaNO3 as N-source) at shake-flask-scale vs. alternative C-source versions, soluble starch and sugarcane molasses led to efficient SC production. On the other hand, oxalic acid byproduct varied with C- and N-sources, with no clear detrimental relationship with SC production. Afterwards, at 3 L bioreactor scale, a starch-based medium led to the highest SC production (7.95 g/L), best recovery efficiency (~52%) and high values of volumetric and specific productivities (0.11 g EPS/L hand 0.018 g EPS/g h respectively). Sugarcane molasses, though leading to lower SC production (5.11 g/L), could be envisaged as a promising agroindustrial sub-product as alternative substrates for efficient, low-cost, and scalable SC production,thus opening new perspectives for medium reformulation and sustainable and economic SC production.