Abstract
Nata de coco, an edible bacterial cellulose (BC) product, is a traditional dessert fermented in coconut water. Production of Nata de coco by Komagataeibacter nataicola is enhanced by pre-fermented coconut water, but its instability is a challenge. Here, BC production by K. nataicola Y19 was significantly improved by Saccharomyces cerevisiae 84-3 through shaping the metabolite profile of the coconut water. Different fermentation time with S. cerevisiae 84-3 resulted in distinct metabolite profiles and different promoting effect on BC yield. Compared to unfermented coconut water, coconut water fermented by S. cerevisiae 84-3 for 1d and 7d enhanced BC yield by 14.1-fold and 5.63-fold, respectively. Analysis between unfermented coconut water and 1d-fermented coconut water showed 129 significantly different metabolites, including organic acids, amino acids, nucleotides, and their derivatives. Prolonged fermentation for 7d changed levels of 155 metabolites belongs to organic acids, amino acids, nucleotides and their derivatives. Spearman correlation analysis further revealed that 17 metabolites were positively correlated with BC yield and 21 metabolites were negatively correlated with BC yield. These metabolites may affect energy metabolism, cell signaling, membrane integrity, and BC production by K. nataicola Y19. The further verification experiment gave the view that BC yield was not only closely related to the types of metabolites but also the concentration of metabolites. This study provides a novel theoretical framework for a highly efficient BC fermentation system utilizing stable fermented coconut water mediums.