Enhancing Productivity and Material Properties Through Repeated Harvest

Bacterial cellulose (BC), a promising versatile biopolymer produced by bacteria, has immense potential in various industries. However, large-scale application is hindered by high production costs and low yields. This study introduces an innovative approach combining a prolonged static culturing with intermittent harvesting. This novel strategy resulted in a significant increase in BC productivity, achieving up to a threefold rise in biomass within the first 35 days. Prolonged growth and continuous harvesting not only enhanced productivity but also led to a mutant strain M2 with higher yields and distinct BC architecture.

Mechanical and structural analyses revealed that sequential harvest correlated with increasing crystallinity, altered crystallite sizes, and improved stiffness of the dry material during initial cycles, potentially reflecting bacteria adaptation to resources limitations. Genomic analysis identified key mutations in the M2 strain, including one in the RelA/SpoT enzyme, suggesting a reduced stringent response that promotes growth under nutrient-limiting conditions. Untargeted metabolomic profiling revealed deregulation of several metabolites, including a significant difference in fatty acid metabolites that could potentially influence membrane fluidity and BC secretion. Such metabolic and structural adaptations enhance BC production efficiency and material properties.

The findings by the interdisciplinary team, which also included Cluster members Bastian Beyer, Cécile Bidan, Skander Hathroubi, and Regine Hengge, highlight the potential of intermittent harvesting for sustainable BC production and the role of bacterial adaptation in tuning BC properties. Further research will optimize this strategy and expand its applications in developing tailored biomaterials for diverse industries.

The article is published in Biofilm, Volume 9, June 2025, 100276, and can be found under https://doi.org/10.1016/j.bioflm.2025.100276.