• Microbiology and Biotechnology Letters
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• v.11 no.3
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• pp.175-180
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• 1983

Thialysine significantly inhibited the growth of wild type strain Gondida utilis NCYC-359. In the absence of thialysine, the culture reached stationary phase after 24hr, however, in the presence of 0.5% thialysine, the culture reached stationary phase after 40hr, respectively. Effect of amino acid or vitamin was investigated on recovery of the growth of wild type strain from thialysine inhibition. Glycine, methionine, arginine and tryptophan recovered growth inhibition by thialyslne to some extent. However, vitamins were inert. Especially, lysine at one eighth concentration of thialysine recovered almost fully the growth inhibition. Thialysine resistant mutants were induced from the parent strain of Condida utilis NCYC-359 by NTG treatment. Colonies of thialysine resistant mutants were obtained on agar minimal medium supplemented with 0.1-0.5% thialysine. The frequency of thialysine resistant mutants induced by the first mutation was the highest at 0.1% The wild strain produced no appreciable lysine extracellularly. However, almost thialysine resistant mutants excreted appreciably. Lysine excretion increased after repeated mutation. Finally, of the thialysine resistant mutants induced by NTG, Condida utilis TRN-4006 was obtained. This strain excreted lysine (400$\mu\textrm{g}$/$m\ell$) into the medium with a concomitant decrease of lysine in the intracellular pool.

• Journal of Aquaculture
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• v.13 no.1
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• pp.55-62
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• 2000

A 10-week feeding trial was conducted to investigate the effects of several yeasts with or without chemical treatment (protoplasted) in formulated diets on growth and body composition of juvenile abalone(Haliotis discus hanai). There replicate groups of the abalone average weighing 210 mg were fed one of eight isonitrogenous (30%) and isolipidic (4.4%) diets containing 3% Kluyveromyces fragilis protoplasted K. fragilis Candida utilis protoplasted C. utilis, Saccharomyces cerevisiae protoplasted S. cerevisiae or brewer's yeast. In addition these formulated diets were compared with commercial diet. Survival rate and proximate analysis of soft whole body of abalone were not significantly affected by the different dietary yeasts and commercial diet (P>0.05) Body weight gain and soft body weight control diet and diets containing S. cerevisiae or brewer's yeast (P<0.05) Shell length of abalone fed yeast and commercial diet (P<0.05) Th results suggest that protoplasted K. fragilis as an additive in this formulated diet can improve weight gain of abalone.