Growth Media Optimization for Production of Alkaline Protease from Industrial Wastewater using Bacillus subtilis PTCC 1254

Abstract

Alkaline proteases are widely used in industrial processes due to their high pH tolerance and thermal stability. In present work, the protease producing ability of Bacillus strains (Bacillus subtilis PTCC 1254, B. subtilis PTCC 1156 and B. subtilis PTCC 1715) was studied. B. subtilis PTCC 1254 showed the highest proteolytic activity and therefore, the strain was selected as the biological agent in the submerged fermentation. Cell growth kinetic model was investigated using Malthus and Logistic equations, which were relatively well fitted to the experimental data. The maximum specific growth rate for Malthus and Logistic models were 0.187 and 0.377 h -1 , respectively. The optimum culture conditions were defined as follows: pH 9, temperature 37°C, fermentation time 72 h, agitation speed 150 rpm and 4% inoculum with medium contained 1 g/l CaCl2, 0.6 g/l K2HPO4, 1 g/l KH2PO4, 0.2 g/l MgSO4.7H2O, 2 g/l sugarcane bagasse and 4 g/l corn bran as carbon and nitrogen sources. A 25% v/v industrial wastewater containing starchy waste was used as main substrate. Under optimum conditions, maximum alkaline protease activity of 117.43 U/ml was achieved. Also, the obtained protease was able to remove blood stain from cotton fabric and hydrolyze gelatin of X-ray film. Thus, this protease showed potential applications in detergent and photographic industries.

Molecular Characterization and Optimization of Alkaline Protease Production by Bacillus cereus LS23B

“…JKSP1. A closer temperature of 37 o C (88.14 U/mL) enhanced the protease activity of Bacillus subtilis PTCC1254 isolated from wastewater as reported by Jafari et al [16]. However, a lower temperature of 20 o C enhanced the protease production of Bacillus sp.…”

“…Researchers have reported Bacillus species for protease production. Jafari et al [16] identified Bacillus subtilis PTCC 1254 isolated from wastewater as a potent protease producer. Hashmi et al [14] also identified Bacillus subtilis S1 and Bacillus amyloliquefaciens KSM12 as the two highest protease-producing microbial strains from soil habitats.…”

“…The use of microbial strains, especially bacteria species, also makes their genetic manipulation much easier because of the organisms' short generation time and simple genetic makeup [11]. Microorganisms that produce protease have been isolated from habitats such as rotten dried fish, hot springs, soil, leather industry effluents, and industrial wastewater [12][13][14][15][16]. It is easier to isolate and screen for microorganisms with desired characteristics since they are found in different environments [17].…”

The fermentation optimization for alkaline protease production by Bacillus subtilis BS-QR-052

“…Numerous studies have indicated that in most cultivation conditions, species of Bacillus , like Bacillus subtilis , produce extracellular alkaline proteinases during the late exponential and stationary phases of batch culture growth ( Singh et al, 2004 ; Zhou et al, 2019 ; Jafari et al, 2023 ). This pattern aligns with the consistency observed in our study, both before and after the optimization of the medium and fermentation conditions.…”

“…Furthermore, other microbial species, such as Pseudomonas aeruginosa ( Saleem, 2012 ), also exhibit similar fermentation patterns when synthesizing alkaline proteases. The model demonstrates that in Bacillus fermentation processes with shorter cycles (10–30 h), the peak activity of alkaline protease occurs 2–12 h after the point of maximum biomass ( Singh et al, 2004 ; Subba Rao et al, 2009 ), while in longer fermentation cycles (60–80 h), the peak activity of alkaline protease lags behind the time of highest cell density by 30–38 h ( Saleem, 2012 ; Jafari et al, 2023 ). However, the stage of the cell growth cycle at which extracellular protease synthesis reaches its maximum has been a topic of ongoing debate.…”