BACKGROUND: Acetoin is a natural flavor commonly used in wine, buffer, honey, garnet berry and strawberry as a food additive. It also has been widely applied in cosmetics, pharmacy and chemical synthesis. Culture medium optimization and process control were carried out for efficient production of acetoin by a newly isoliated P. polymyxa CS107. RESULTS: An acetoin high producing strain, designated as CS107, was newly isolated and identified as P. polymyxa based on its physiological and biochemical characteristics as well as the 16S rDNA sequence. The medium composition was optimized in shake flask fermentations by a sequential statistical experimental design. Under the optimized conditions, acetoin concentration of 30.98 g L-1 was achieved with 71.83% of theoretical glucose conversion efficiency. Fed-batch fermentation based on a suitable agitation speed was carried out in a 5 L jar, the maximum acetoin concentration of 55.3 g L-1 was obtained with the productivity of 1.32 g L-1 h-1 and the yield of 75.62%. CONCLUSION: A new strain for efficient production of acetoin, designated as P. polymyxa CS107, was obtained. The optimization of fermentation variables and fed-batch culture resulted in a maximum acetoin concentration of 55.3 g L-1 in 5 L jar. Copyright (c) 2012 Society of Chemical Industry