Kinetic and Thermodynamic Characterization of Lysine Production Process in Brevibacterium lactofermentum
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Kinetic and Thermodynamic Characterization of Lysine Production Process in Brevibacterium lactofermentum Sibtain Ahmed & Munazza Afzal & Muhammad Ibrahim Rajoka
Received: 3 January 2013 / Accepted: 27 February 2013 / Published online: 10 March 2013 # Springer Science+Business Media New York 2013
Abstract Detailed kinetic and thermodynamic parameters for lysine production from Brevibacterium lactofermentum are investigated for the first time in this study. Production of the essential amino acid, L-lysine, by B. lactofermentum was assessed in a flask and a continuously stirred tank fermentor (22 L). Maximum lysine production was achieved after 40 h of growth and at 35 °C. The effect of different nitrogen sources such as NH4NO3, (NH4)2SO4, (NH4)2HPO4, corn steep liquor, NaNO3, and urea showed that corn steep liquor gave a better lysine yield. Lysine production was increased when dissolved oxygen was maintained at 50 % saturation. The use of dissolved oxygen was critical for high productivity. This indicates that dissolved oxygen greatly affects L-lysine productivity. Kinetic and thermodynamic parameters during lysine production from molasses and glucose mixture showed that B. lactofermentum efficiently converted the substrate mixture into cell mass and lysine. Kinetic and thermodynamic parameters were significantly higher compared with other microorganisms which may be due to the high metabolic activity of B. lactofermentum. This study will have a significant impact on future strategies for lysine production at industrial scale. Keywords Batch fermentation . Brevibacterium lactofermentum . Kinetics . Lysine . Thermodynamics
S. Ahmed (*) University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA e-mail: [email protected] S. Ahmed Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad 38040, Pakistan M. Afzal : M. I. Rajoka National Institute for Biotechnology and Genetic Engineering, 577 Faisalabad 38000, Pakistan M. I. Rajoka (*) Government College (GC) University, Allama Iqbal Road, Faisalabad 8000, Pakistan e-mail: [email protected]
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Appl Biochem Biotechnol (2013) 170:81–90
Introduction Biotechnological production of amino acids today serves as a market with strong prospects of growth. In the foreground are the fermentation processes, which are now widely established in the production of amino acids [1]. It is expected that the demand for amino acid production will increase in the future [2]. Deficiency of lysine in cereal grains limits the usefulness of the cereal protein. Lysine is nutritionally important for humans and animals. It cannot be synthesized internally and needs supplementation [3]. Lysine also acts as a precursor for glucose, glycogen, and lipids in the human body and hence works for energy production. It also promotes formation of collagen and enhances bone growth. L-Lysine–arginine mixture has several therapeutic applications. It helps in the release of human growth hormone, lowering blood cholesterol, increasing immunity against viru
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