Isolation and partial characterization of Komagataeibacter sp. SU12 and optimization of bacterial cellulose production using Mangifera indica extracts

Abstract

Background: Recycling food wastes into high-value-added products not only impacts beneficially on the environment but also on local economies. Mango wastes represent more than 92 000 tons per year in Peru. Bioconversion of mango waste into bacterial cellulose (BC) can provide valuable products in biomedicine. Results: Screening of BC producers in kombucha tea allows the selection of wild-type strains. One of the selected wild-type strains, named SU12, was cultured in batch using Hestrin–Schramm (HS) synthetic medium under static conditions and was able to produce a membrane in the liquid–air interface. The membrane was purified and characterized by chemical (Congo red), spectroscopic (Fourier transform infrared), thermogravimetric analysis and differential scanning calorimetric techniques as BC. The strain SU12 was tested using chemical and molecular techniques (16S rRNA) and identified phylogenetically as Komagataeibacter rhaeticus SU12 with 99.85% similarity and 96.5/1/98 values of Shimodaira–Hasegawa approximate similarity test/aBayes/bootstrap analyses. HS medium supplemented with mango extracts was optimized using Plackett–Burmann's design followed by factorial design of relevant parameters and adjusted by regression to a first-order polynomial equation. Optimized major parameters of mango extract, yeast extract, ethanol concentration and incubation time produced 25.34 g L−1 dry cellulose in 21 days. Conclusions: The study demonstrated the isolation of wild-type strain identified as K. rhaeticus SU12 capable of producing BC using synthetic medium supplemented with extracts of mango wastes and high BC production comparable with other members of the same species.