title: A new strategy to enhance gellan production by two-stage culture in Sphingomonas paucimobilis.
abstract: The effects of different initial sucrose concentrations and temperatures on gellan biosynthesis by Sphingomonas paucimobilis ATCC 31461 were investigated. Lower sucrose concentrations and higher temperatures were favorable for cell growth. Higher sucrose concentrations and lower temperatures promoted gellan production but retarded cell growth. Based on these results, a two-stage culture strategy was developed to improve gellan production. During the first 24 h, S. paucimobilis was cultured in a pulse fed-batch mode with an initial sucrose concentration 10 g/L. Ten grams per liter of sucrose were added at 12 h and 24 h, and the temperature was controlled at 33 °C. Batch culture was performed, and the temperature was reduced to 28 °C to achieve a high gellan accumulation. The two-stage culture strategy achieved the highest gellan production (22.61 g/L) at 60 h that was 35.71% higher than the result of the best conventional batch operation (16.66 g/L). Meanwhile, high gellan yield was related to high UDPG-pyrophosphorylase activity and glucosyltransferase activity.
authors.affiliation: School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: Guilan
authors.initials: G
authors.lastname: Zhu
authors.forename: Long
authors.initials: L
authors.lastname: Sheng
authors.forename: Qunyi
authors.initials: Q
authors.lastname: Tong
mesh_terms: D046508:Culture Techniques / Q000379:methods*; D005285:Fermentation; D005964:Glucosyltransferases / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D020578:Sphingomonas / Q000254:growth & development* / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism; D013696:Temperature; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000378:metabolism
chemical_list: D011135:Polysaccharides, Bacterial; D013395:Sucrose; C048288:gellan gum; D005964:Glucosyltransferases; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase
keywords: Gellan; Sphingomonas paucimobilis ATCC 31461; Two-stage culture