Amino acids production of locally isolated bacteria in different growth media
Qazi, J., I.; Qureshi, A., W.
Pakistan Journal of Zoology 34(1): 65-71
ISSN/ISBN: 0030-9923 Accession: 010152059
Four strains of amino acid(s) producing bacteria were isolated from a sewage sample on two media containing different inorganic sources of nitrogen. Extracellular production of amino acid(s) by the bacteria ranged from 0.11 to 1.8 mg/ml of broth culture following 72 hours of incubation under optimized conditions of temperature, pH and inoculum size. All the four strains had 37degreeC optimum temperature, both for growth as well as the yield. One strain was found alkalophilic while others showed variable responses of growth and amino acid(s) production to pH values. Growth and amino acid yield optima corresponded to different inocula for all the strains. Addition of 0.1% yeast extract to both media caused significant increase in bacterial growth and production of amino acid(s). One of the two lysine producing Gram-positive strains was found aerobic, while the remaining three as facultative anaerobes. The Gram-negative strains revealed the production of mixtures of amino acids. The Gram-positive strains producing only one kind of amino acid (lys) are of importance because of the ease of separation of the valuable product from culture fluids.