Vitamin requirements of hydrocarbon-utilizing soil bacteria

The numbers of oil-utilizing bacteria in several samples of clean and oil-p olluted soils counted on vitamin-containing media were severalfold higher t han the numbers counted on vitamin-free media. Colonies that grew on a medi um containing a vitamin mixture were tested for growth on the same medium l acking any vitamins. More than 90% of the total colonies failed to grow. Th e remaining 10% grew, yet their growth was enhanced, when vitamins were add ed. The predominant oil-utilizing bacteria in one of the test desert soil s amples were various strains of Cellulomonas flavigena and Rhodacoccus eryth ropolis. Minor organisms belonged to the genera Pseudomonas, Bacillus and A rthrobacter. Two vitamin-requiring biovars of C. flavigena and R. erythropo lis were selected for further study. Their growth on n-octadecane and phena nthrene as sole sources of carbon and energy as well as their potential for hydrocarbon consumption were enhanced by added vitamins, e.g. folic acid, pyridoxine, vitamin B12, biotin and others. In a field experiment, it was c onfirmed that vitamin fertilization of an oil-polluted sand sample enhanced the biodegradation of constituent hydrocarbons of that sample.