A Reduced-Acidification Phenotype Simplifies Strain Engineering in Komagataeibacter and Enables One-Step Production of Melanated Bacterial Cellulose.

Komagataeibacter species are among the highest-yielding bacterial cellulose producers and offer a promising platform for the genetic engineering of functionalized bacterial cellulose. However, routine strain engineering remains limited by inefficient screening of genomic integrants and acidic culture conditions that inhibit acid-sensitive cellulose modifications. Here, we exploited the reduced-acidification phenotype of a Komagataeibacter sucrofermentans glucose dehydrogenase deletion mutant (Δgdh) to overcome both limitations. We developed a simple phenotypic screen based on reduced acidification to identify candidate colonies for subsequent molecular confirmation. We further exploited this phenotype by constructing a Δgdh::tyr1 strain that, after optimizing culture conditions, produced melanated bacterial cellulose in a single step, without the manual pH neutralization required by previous methods. Together, these results establish reduced acidification as a practical engineering phenotype that simplifies strain engineering and enables acid-sensitive modification of bacterial cellulose, thereby expanding the range of bacterial cellulose modifications achievable in Komagataeibacter.