Effects of Biotin Deficiency on Growth, Morphology and Sporulation in Bacillus megaterium NCIB7581

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Abstract
B. megaterium strain NCIB7581 grew at 30.degree. C in a simple chemically defined medium without biotin. At 37.degree. C the bacteria grew more slowly in the same medium and were deformed, especially during the earlier stages of growth, as filaments or with swollen ends. Addition of biotin restored the normal appearance and rate of growth at 37.degree. C. The organisms synthesized more biotin at 30.degree. C (11 ng l-1 in a stationary phase culture) than at 37.degree. C (1.4 ng l-1). Addition of aspartate, malate, fumarate or acetate to minimal medium restored normal morphology and accelerated the growth rate in biotin-deficient medium at 37.degree. C. Neither acetate nor aspartate increased synthesis of biotin at 37.degree. C. After growth in medium containing only 0.2% glucose, almost every organism in the culture was able to sporulate at 30.degree. C, whether or not biotin was added. Fewer spores (.apprx. 50 times) were formed at 37.degree. C without biotin; the yield of spores increased .apprx. 20-fold at this temperature when biotin, aspartate or dipicolinate was added.