Abstract
The present study was an illustrative investigation on L-glutamic acid production by usingCorynebacterium glutamicum employing a cheaply available dates syrup. Owing to the high sugar content of dates syrup (total sugar 80%) attempt was made to utilize the date syrup for the production of glutamic acid, in shaking culture. The acid treated dates syrup (ATDS) at concentration of 100g/L was the best sugar sources in the glutamic production. Penicillin addition at concentration of 4 U/ml after 12 h of incubation was superior in glutamic acid production. The selected temperature-sensitive mutants M5AJ2, showed 13.4% increase in glutamic production while, M5AJ4 and M7AJ6 showed 22.4 and 4.6% decrease respectively, in their glutamic acid production than their wild type bacterial strain. The specific production rate of glutamic acid in case of temperature shift-up from 31 to 39°C increased apparently 2 and 1.5 fold respectively on average from that under the constant temperature. 24g/L pure glutamic acid were precipitated in crystal at pH 3.2. Key words: Glutamic acid, Corynebacterium glutamicum, dates syrup, fermentation, penicillin, mutation, UV, efflux.
Highlights
Glutamate is mainly used as a flavor agent, recently it is known as neurotransmitter, (Hawkins, 2009)
Penicillin addition at concentration of 4 U/ml after 12 h of incubation was superior in glutamic acid production
In comparison between glucose, treated dates syrup with alkali or acid and non treated dates syrup, the results indicated that acid treated was the best sugar source in glutamic production
Summary
Glutamate is mainly used as a flavor agent , recently it is known as neurotransmitter, (Hawkins, 2009). It is widely used in food, pharmaceutical, medical, biochemical and analytical industries. Corynebacterium glutamicum and related organisms are used since 1957 for the production of glutamate (Kinoshita et al, 2004) to meet today an annual demand of approximately 1,500,000 tons. An investigation carried out by other agriculture wastes which are the cheap carbon source such as Muntingia calabura L. are used by Vijayalakshmi and Sarvamangala (2011) for the production of glutamic acid. Pasha et al (2011) tested the UV and chemical mutation for Corynebacterium glutamicum for increasing glutamic productivity In addition to exploitation of wild type strains for amino acid biosynthesis some workers used advanced techniques for improvement of strains by mutagenesis, cloning and protoplasm fusion techniques. Atef et al (2007) utilized mutant cells of Brevibacterium flavum produced by UV irradiation and by ethyl methane sulfonate (EMS) treatments, increased alanine productivity. Pasha et al (2011) tested the UV and chemical mutation for Corynebacterium glutamicum for increasing glutamic productivity
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