Degradation of B-Carotene by microorganisms

In the present study, decomposition of g-carotene by soil microorganisms, comprising bacteria, yeasts, and molds, was investigated aerobically at 28°C. The B-carotene was dissolved in ethyl alcohol and was used in a mineral salt solution at the levels of 0.04 and 0.08% (W/V). The incubation times were 6 weeks for molds and yeasts and 12 weeks for bacteria. The criteria for degradability of g-carotene by microorganisms were the production of cellular mass and the decrease in ammonium-nitrogen in culture solutions. 8-carotene proved to be highly resistant to microbial attack. It was only slightly degraded by Pseudomonas putida, Pseudomonas stutzert, Pseudomonas syneyanea, Flavobacterium sp. #2, Aspergillus niger, Scopulartopsis sp., and a yeast-like fungus. On the other hand, Pseudomonas aerugtnosa, Endomycopsts sp., Penicilltum sp. #1, and Trichotheetum sp. grew quite well in the presence of 0.04% g- carotene; their growth, however, being somewhat reduced at 0.08%. Pseudomonas fluorescens, Flavobactertum sp. # 1, Torula sp., Penicillium species #3 and #6, and Aspergillus sp. were not able to utilize B-carotene as a source of carbon.