Study on the candida tropicalis treated by qigong

A wild strain of candida tropicalis, which can oxidize the n-alkane in petroleum, was treated repeatedly by chemical and physical mutagen such as nitrosoguanidine, nitrous acid, UV and laser to induce a mutant with a lower ability of beta-oxidation and accumulation of more long-chain binary carboxylic acids. We treated candida tropicalis strain 3# and 5# with qigong. In nearly two months of isolation, screening, analyzing and determination, a positive result was obtained.

No significant morphological change was seen in the treated and the original strains, but the rate of growth of single colony changed greatly. On malt plate the original strain was relatively uniform in size, while both treated strains differed significantly in size.

The metabolism of 140 strains of 3# treated and 122 strains of 5# treated was studied. It was shown that among them 40 and 34 strains (28.6% and 27.9% respectively were of positive change (increase of amount of acid yield > 15%); 28 and 50 strains (20% and 41% respectively) were of negative change (decrease of amount of acid yield > 15%; 72 and 38 strains (51.4% and 31.1% respectively) were unchanged (decrease or increase of amount of acid yield within 15%).

After 10 strains of 3# with increase of acid yield >40%, were selected 3 times, 2 strains 3-3 (60) and 3-1 (10) which had good reproducibility were obtained which had acid increase of 44.5% and 33.5% in average respectively, After 3 times selection of 5# treated strain, 2 strains with an averaged increase of acid yield, 34.1% and 21.3%, were obtained respectively.