Influence of B‐vitamins and trace elements on lysine production by micrococcus varians 2Fa

Abstract

A hydrocarbon utilizing strain of iVicrococcus vuriuns 2Fa isolated from local soil has been found to yield lysine 2.6 g 1-l. Addition of B-vitamins and trace elements to the optimal media, has been found to stimulate growth and enhance lysine yield. KINOSHITA [l] isolated a glutamic acid producing Micrococcus glutamicus ever since microbial production of amino acid has become an established branch of industrial microbiology. Among the other amino acids, microbial production of lysine has been extensively studied. Extracellular lysine production is not restricted to any particular group of microorganisms, though the high yielding strains are mostly the species of Arthrobacter, Corynebacterium and Brevibacterium. During the screening of lysine producing bacteria from among the hydrocarbon utilizers, a strain of Micrococcus varians 2Fa was isolated [2]. Later some of the optimal conditions have been studied [3]. This communication reports the effect of some B-vitamins and trace elements on growth and extracellular lysine yield. Materials and MethodsThe organisms was grown in 250 ml ERLENMEYER flasks with 50 ml modified (0.1% (w/v) nitrogen source and with 4% straight run gas oil as the carbon source) synthetic medium of MAKULA and FINNEBTY [4] and was sterilized by autoclaving. However, the straight run gas oil was sterilized by filtration (Jena G 5). The flasks were inoculated with an aqueous suspension of bacteria (2% v/v) from 24 h old adapted cells grown in the same medium and incubated a t 30°C on a rotary shaker (120 rpm) for 72 h. Initially the medium was made free of trace salts used, following the method of BANERJEE and NANDI[5]. All the stock solution of vitamins and trace salts were sterilized separately by filtration (Jena G 5) and added to the medium aseptically as required. Growth was measured in terms of constant dry weight of washed bacterial cells. Extracellular lysine was measured colorimetrically [6]. The experiment was repeated three times with six replicates each time and the mean values are presented. DUNCAN'S multiple range test was used to calculate the statistical significance at 5% level [7].

Influence of Antibiotics and Surfactants Addition on Growth and Methionine Productivity by <i>Bacillus cereus</i>

“…There are no reports on the effect of antibiotics on methionine production. [9,17] have reported increased amino acid production in the presence of small quantities of several kinds of antibiotics, although the exact role played by these antibiotics is not clearly understood. [18] suggested that a change in permeability of the cell wall caused by antibiotics may be responsible for improved yield.…”

“…However, alteration of these mechanisms can lead to L-methionine accumulation [6,7]. The influence of antibiotics and surfactants on amino acid production by bacterial organism has been reported [8][9][10][11] although the exact role played by these antibiotics and surfactants are not clearly understood. In our previous work, we reported the production of L-methionine by three methionine yielding strains of Bacillus cereus isolated from different soil ecovars in Owerri, Nigeria [12,13].…”

Lysine Production of <i>Microbacterium lacticum</i> by Submerged Fermentation Using Various Hydrocarbon, Sugar and Nitrogen Sources

“…No production of lysine by Microbacterium species has been reported. Although Sen and Chatterjee [20], Ekwealor and Obeta [18] noted that the yielding strains are found mostly among species of Arthrobacter, Corynebacterium, Brevibacterium and Bacillus.…”

“…These isolates produced lysine on solid medium and were termed lysine producers. 20.0 g and (NH 4 ) 2 SO 4 , 10.0 g; served as a carbon and nitrogen sources respectively, and the medium sterilized at 115˚C for 10 min. one milliliter volume of the seed inoculum (Ca 5.6 × 10 8 cells/ml) was inoculated into duplicate 100 ml Erlenmeyer flask containing 20 ml of fermentation medium.…”

Optimization of Fermentation Conditions of <i>Bacillus thuringiensis</i> EC1 for Enhanced Methionine Production

“…Tani et al [27], reported a high methionine yield when 200 µg/l thiamine was added to the fermentation medium in methylotrophic yeast, Candida biodinii. Sen and Chatterjee [28], noted that thiamine HCl stimulated lysine accumula- tion in Micrococcus varians 2fa. Ekwealor and Obeta [29], reported improved lysine yields in Bacillus megaterium SP 86 and Bacillus megaterium SP 76 with the addition of 10 µg/ml and 100 µg/ml of folic acid and riboflavin respectively.…”