Microbial production of zeaxanthin from algal biomass and waste glycerol using a newly isolated agarolytic marine bacterium Cellulophaga omnivescoria MSK1

With increasing interests in the biological conversion of waste resources into value-added chemicals and biocompounds, algal biomass has emerged as a promising renewable feedstock due to abundance, rapid growth, and sustainability. However, efficient bioconversion method is still being challenged due to the lack of suitable host strain capable of directly utilizing algal biomass and converting into desired products. In this study, a potent marine bacterium capable of producing zeaxanthin from algal biomass was investigated. The agarolytic bacterium, Cellulophaga omnivescoria MSK1 was isolated from coastal seawater. Through physiological and morphological analysis, it was confirmed that this bacterium degrade agarose into neoagarotetraose (NA4) and neoagarohexaose (NA6) and produces zeaxanthin using agarose as a carbon source. This bacterial strain demonstrated the ability to produce 2.23 ± 0.19 mg/L of zeaxanthin when provided with 0.2% agarose as a carbon source. By supplementing with glycerol, zeaxanthin production was further enhanced, reaching levels of 8.43 ± 0.31 mg/L, with a content of 6.77 ± 0.3 mg/g CDW (cell dry weight). These results suggest that an agarolytic Cellulophaga omnivescoria MSK1 strain has a great potential to be used as a platform microbial strain capable of producing zeaxanthin from algal biomass as a sustainable feedstock.