Bacterial Cellulose Cultivations Containing Gelatin Form Tunable, Highly Ordered, Laminae Structures with Fourfold Enhanced Productivity.

Manipulation of bacterial cellulose (BC) morphology is important to tune BC properties to meet specific application requirements. In this study, gelatin was added to cultivation media at 0.1-7.5 wt %. After cultivations, gelatin was removed from the BC matrix, and its effects on BC matrix characteristics and fermentation production efficiency were determined. Higher contents of gelatin in cultivation media (up to 5%) resulted in BC that, from scanning electron microscopy observations, had larger pore sizes and formation of a lamina morphology that was highly unidirectional. Crystallinity remained unchanged between 0.1 and 5 wt % gelatin concentrations (92-95%); however, it decreased to 86% at a gelatin concentration of 7.5 wt %. Mechanical properties showed a positive trend as both the specific modulus and specific strength values increased as the gelatin concentration increased to 5 wt %. A breakdown in the ordered structure of the BC matrix occurs at 7.5 wt % gelatin, with corresponding decreases in the specific modulus and specific strength of the BC. The productivity increased by almost 4-fold relative to the control, reaching 1.64 g·L