Effects of NaCl and pH on Carbon Source Metabolism Ability of Proteus vulgaris and Hafnia alvei

Proteus vulgaris and Hafnia alvei were spoilage organisms isolated from lightly-salted large yellow croaker at 5 ℃. To analyze the effects of environmental factors on the carbon source metabolism of Proteus vulgaris and Hafnia alvei,BIOLOG was used to analyze the carbon source metabolism of two strains under different NaCl concentration and pH conditions at 5 ℃. The carbon source metabolism ability of Proteus vulgaris and Hafnia alvei was evaluated by the number of positive wells,the average well colour development,the utilization area and principal component analysis. The results showed that,the two strains digested similar carbon sources,such as sugars,carboxylic acids,amino acids and hexose phosphates. The effects of NaCl on the metabolism of the two strains increased with the increase of its concentration,and the metabolism was almost completely inhibited under 5% NaCl concentration. By comparison,the effects of pH on the carbon source metabolism of two strains were not obvious. The inhibition effects of pH(5.0~7.0)on the carbon source metabolism of the two strains increased with the decrease of pH values,but the overall inhibition effect was not significant. Conclusion:The increase of NaCl concentration could gradually inhibit the carbon metabolism of the two strains. When NaCl concentration increased to 3%,it almost completely inhibited the strains. In the range of pH5.0~7.0,the carbon source metabolism of the two strains had little effect.