Nitrogenase activity of Beijerinckia derxii is preserved under adverse conditions for its growth

Abstract

In order to evaluate the response of Beijerinckia derxii ICB-10 to different environmental factors, growth curves and specific nitrogenase activity were studied. Tested conditions were as follows: a) media with different pH values (2.5, 2.8, 4.2 and 5.7); b) medium supplemented with 230 µM aluminium sulphate; c) media with two different potassium phosphate concentrations (50 mM and 100 mM); d) shaken or still cultures; e) medium supplemented with 40 mM sodium thiosulphate. Growth curves and specific nitrogenase activity at pH 4.2 were closely similar to those for cultures at pH 5.7 (standard condition), whereas no growth occurred at pH 2.5. Changes in growth curves and/or specific nitrogenase activity were observed under the following conditions: I) pH 2.8 (decrease in initial CFU number, reduction of maximum specific growth rate, reduced number of generations and stimulation of nitrogenase activity), II) presence of aluminium (early death phase), III) 50 mM PO4 3-(reduction of maximum specific growth rate), IV) 100 mM PO4 3-(reduction of both number of generations and maximum specific growth rate as well as early death phase), V) low O2 availability (increasing nitrogenase activity), and VI) presence of thiosulphate (reduction of maximum specific growth rate; early death phase and high stimulation of nitrogenase activity). The data obtained showed the high variability of the cell growth response to environmental factors. Nitrogenase activity was always preserved even when population growth was affected.

Characterization of brown-black pigment isolated from soil bacteria,Beijerinckia fluminensis

“…In shaker conditions, the cells utilize growth nutrients faster and move early to the stationary phase, which results in the transition of older cells to stress conditions, leading to melanin production (Fig. 5) [10,11].…”

“…Barbosa et al [10] observed an increase in slime production and cell density in B. derxii over the time when glucose was the sole carbon source. Barbosa et al 2002, have also shown that co-factors like metal salts and aerobic conditions are essential for the cell growth and specific nitrogenase activity of B. derxii strain ICB-10 [11]. Becking, observed that Beijerinckia species grow in the pH range of 3.0 to 9.0 at an optimal temperature of 25 ° C to 30 ° C [12,13,14].…”

Atmospheric Nitrogen Fixing Capacity of Azotobacter Isolate from Cooch Behar and Jalpaiguri Districts Soil of West Bengal, India

“…Acid tolerant strains Beijerinckia derxii racts differently to aluminium. Barbosa et al, (2002) observed that a decline in the number of CFU was observed immediately after the end of the exponential phase.…”

Survey on nitrogenase evolution by considering the importance of nitrogenase, its structure, and mechanism of nitrogenase

“…Within the catalytic MoFe protein, the M-cluster is ligated by an organic homocitrate and two residues: C275 and H442. Structural homologs to the M-cluster consist of the native V-cluster [VFe7S9C] (substitution of molybdenum with vanadium) and symmetric L-cluster [Fe8S9C] (Georgiadis et al, 1992;Barbosa et al, 2002;Huang et al, 2021). In all nitrogenase systems, Fe proteins couple the transfer of an electron achieved from either a ferredoxin or a flavodoxin to their cognate dinitrogenase (MFe protein, with M = Mo, V or Fe) to the hydrolysis of two molecules of ATP per electron; three dimensional structure of the complex of the two constituents of Mo-nitrogenase, Fe protein NifH, and the MoFe protein NifDK, and the complex is shaped transiently for each single electron transfer and the overall reaction demands at least 8 electrons per N2 (Trncik et al, 2022).…”

“…The nitrogenase enzyme complex (the nitrogen, fixing enzyme) is sensitive to O2, that irreversible inactivates the enzyme, and diazotrophs must engage in mechanisms which on the other hand allow the supply of O2 required for energy regeneration and protect Nase from the deleterious impacts of O2, and they have developed diverse ways for limiting O2 access to Nase: 1) It could avoid O2 and live in environments which are constantly anaerobic, 2) Alternatively, it could generate a physical barrier around its Nase and in this way block O2 from diffusing to the enzyme, 3) The microorganism could, but its metabolism, decrease the concentration of O2 within the vicinity of Nasa, 4) They could adjust its Nasa in such manner as to render it resistant to inactivation by O2 (conformational protection), 5) Finally, the microorganism could merely balance Nasa inactivation with the synthesis of new enzyme (Miller and Orme-Johnson, 1992;Soto-Urzua and Baca, 2001;Byer et al, 2015). Nitrogenase activity was always maintained even when population growth was influenced, and the stimulus may be very high during the stationary or death steps, conditions in which bacteria are frequently found in the environment (Richards, 1996;Barbosa et al, 2002). Nitrogenases are composed of two protein that can be purified individually: dinitrogenase and dinitrogenase reductase (Bulen and LeComte, 1966;Hageman and Burris, 1978;Barriere et al, 2001).…”