Bioinformatic Analysis of Glucose Transporters of Gluconobacter oxydans

Abstract

Gluconobacter oxydans is a gram-negative bacillus whose unique metabolism is frequently exploited in industry and biotechnology for its metabolic byproducts. Glucose is a common carbon source for G. oxydans and is incompletely oxidized by membrane-bound dehydrogenases. Nearly 90% of glucose is oxidized in the periplasm, and the remaining 10% is transported by unknown transporters into the cytoplasm. Glucose and periplasmic products of oxidation are further utilized primarily by the pentose phosphate pathway (PPP), since G. oxydans is lacking genes that encode the complete tricarboxylic acid (TCA) cycle or glycolysis. Products from the PPP support biosynthesis and respiration for growth and division. However, how glucose enters G. oxydans cells remains elusive despite the completion of the G. oxydans genome sequence. Glucose transport is hypothesized to be facilitated by either a simple active transporter or an ATP-binding cassette (ABC) system. G. oxydans likely does not use a common phosphotransferase (PTS) system since a functional PTS system is not encoded in the genome. Our work aims to identify the glucose transporter(s) based on bioinformatic and functional analyses of predicted active transporters of G. oxydans and other similar transporters within the class Acetobacteraceae. The identification of the glucose transporter(s) has great industrial implications for optimizing growth and carbon flow for current and future commercial production.