Game-changer for rare sugars: alkaline media unlocks high yield of rare sugars from bacteria

Rare sugars possess high economic value in nutraceutical and pharmaceutical applications, yet their limited natural availability necessitates biotechnological or chemo-catalytic production. Bacterial EPSs are emerging as a sustainable source of rare sugars, offering advantages including higher yields and lower environmental impact.

Scientists isolated 28 bacterial strains producing EPSs from Arachis pintoi roots and rhizosphere and identified 2 strains as significant EPS producers. The EPSs from these strains were characterized as heteropolysaccharides comprising 8 distinct monosaccharides, including several rare sugars, which may contribute to their notable antioxidant activity.

EPS production and composition are significantly influenced by pH conditions, with alkaline media markedly enhancing EPS yields by up to 238.92%. Alkaline cultivation media also suppressed the production of galactose, galacturonic acid, and fucose in Enterobacter sp., while inducing ribose production in Klebsiella sp. These adaptive changes suggest a strategic bacterial response to environmental factors, indicating optimization of environmental factors, particularly pH, could enhance both EPS yield and bioactivity, paving the way for industrial-scale production.