Production of 2,3-Butylene Glycol from Citrus Wastes. II. The Bacillus polymyxa Fermentation

The conditions required for production of levo 2,3-butylene glycol by Bacillus polymyxa from citrus molasses were studied. Starter cultures required acclimatization to the substrate prior to inoculation of the fermentation medium. Maximal production of butylene glycol with minimal residual sugar was obtained with a medium consisting of molasses, diluted to 20 degrees Brix, and 0.4% urea. Optimal environmental conditions included aeration at 0.11 volumes of air per volume of medium per minute, maintenance of pH at 6.0 to 6.2, a fermentation temperature of 30 C, and a stirring rate of 420 rev/min. The concentration of butylene glycol obtained in the fermentation beer ranged from 2.3 to 4.4%. The optical rotation of the glycol ranged from alpha](D) (23 degrees ) = -1.01 degrees to -10.45 degrees . The variation in rotation was probably due to the presence of contaminating substances in the distillate.