Japanese researchers find bacterial exopolysaccharides changed by feeding them differently

In Japan, changing the carbon source used during bacterial fermentation—essentially, what bacteria are fed—can significantly influence the properties of the sugar polymers they produce, known as bacterial exopolysaccharides (EPSs).

These EPSs are secreted by bacteria into their surroundings, where they form protective layers or biofilms and serve as valuable materials for a wide range of medical and industrial applications.

Researchers at Hiroshima University compared the effects of two distinct carbon substrates—refined sucrose and sugarcane molasses, an inexpensive agricultural by-product—on the EPSs produced by the bacterium Bacillus velezensis AZU-A3. Using vacuum-ultraviolet circular dichroism spectroscopy at Hiroshima University’s HiSOR, together with chromatographic tools, the team mapped the structural variations among the resulting polymers.

The results, published in the Chemical Engineering Journal on June 23, 2026, showed that refined sucrose yielded a biopolymer (EPS-S) characterized by an ordered, helical-like molecular conformation. Conversely, sugarcane molasses produced a glucose-rich biopolymer (EPS-M) with a more flexible molecular conformation.

Tags: Japan, sugar polymers

Category: Research