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Citrobacter freundii bacteria were grown in LB medium containing cadmium ion. In order to reduce adverse effect caused by cadmium, different concentrations of vitamin C, were added to the growth medium. While the concentration of bacteria grown was determined by spectrophotometer, the amounts of water and fat-soluble vitamins were also determined by HPLC. The cadmium concentration varied from 0 (control), to 10, 20, 40, 60, 75, 100, 125 ppm in LB growth medium. The effect of cadmium has not been observed on the growth of bacteria, up to 40 ppm, on the other hand no significant microorganism growth was observed over 150 ppm cadmium. Significant change of bacteria concentration was observed in the medium containing 75, 100 and 125 ppm Cd. Microorganism concentrations decreased 18.8, 40.5 and 45.5 percent in the growth medium containing 75, 100 and 125 ppm Cadmium respectively. With the addition of 75 ppm vitamin C to the same growth medium, microorganism concentration was decreased about 2.0, 28.0 and 31.0 percent, respectively compared to the control. In addition, fat and water-soluble vitamins in bacteria grown in cadmium-containing medium was decreased in comparison to the control (p<0.05). With the addition of 25, 50 and 75 ppm vitamin C to cadmium-containing medium, fat and water soluble vitamin concentrations were increased. As a result, it can be said that the negative effects of cadmium on bacterial growth and vitamin content can be reversed by the addition of vitamin C in to the growth medium of bacteria.

In this study, Citrobacter freundii (NRRL B-2643) bacteria were grown in LB medium containing varying concentrations of cadmium (Cd). In order to reduce the negative effect of Cd, different concentrations of vitamin C, known for its antioxidant properties, were added to the Cd-containing growth medium. Bacterial concentration, soluble protein and activities of antioxidant enzymes (Glutathione peroxidase (GSH-Px), Glutathione reductase (GSH-Rd), Superoxide dismutase (SOD), Catalase (CAT) and peroxidase (POD)) were determined by spectrophotometer. In addition, reduced and oxidized glutathione (GSH and GSSG), 4-hydroxyneoneal (4-HNE), malondialdehyde (MDA) amounts were determined by HPLC. No significant microorganism growth was observed at 150 ppm and higher Cd concentrations. Bacteria production was not affected up to 40 ppm Cd concentration. Bacteria were grown in media containing 0, 75, 100 and 125 ppm Cd. The protein content of the microorganism grown in the medium containing 75, 100 and 125 ppm Cd decreased about 24, 44 and 62 percent, respectively, comparisons to the control. When 50 ppm of vitamin C was added to the same growth medium, the percentage decrease in protein amount compared to the control was found to be 10, 31 and 50, respectively. An increase was observed in the antioxidant enzymes activities and stress markers in bacteria grown in cadmiumcontaining media compared to the control (p<0.05). With the addition of 25, 50 and 75 ppm vitamin C to cadmium-containing media, a decrease was observed in the activities of antioxidant enzymes and the amounts of stress markers.

Bu çalışmada, Citrobacter freundii farklı konsantrasyonlarda kadmiyum içeren LB besiyerinde üretildi. Kadmiyum içeren besi yerine değişik konsantrasyonlarda selenyum katılarak, üretilen hücre konsantrasyonu, ve bazı biyokimyasal parametreler spektrofotometre ve HPLC ile belirlendi. Bakteriler 0 (kontrol), 75, 100, 125 ppm kadmiyum (Cd) içeren besi ortamlarında üretildi. Kontrol ile 75, 100 ve 125 ppm Cd içeren gruplar karşılaştırıldığında, bakteri, vitaminler ve indirgenmiş glutatyonun (GSH) konsantrasyonlarında azalma, yükseltgenmiş glutatyon (GSSG), malondialdehit (MDA) ve 4-hidroksineoneal (4-HNE) konsantrasyonlarında ise artış gözlendi (p<0.05). 75, 100 ve 125 ppm Cd içeren besi ortamına 1.0 ve 3.0 ppm selenyum (Se) katılmasıyla birlikte, bakteri, vitaminler ve GSH konsantrasyonlarında artış, GSSG, MDA ve 4-HNE konsantrasyonlarında ise azalma gözlendi. Bu bulgulardan, kadmiyumun olumsuz etkisini, bakteri besi yerine katılan selenyumun azalttığı söylenebilir.