Zübeyde Baysal

Solid state fermentation for production of α-amylase by a thermotolerant Bacillus subtilis from hot-spring water

Abstract The production of extracellular α-amylase by thermotolerant Bacillus subtilis was studied in solid state fermentation (SSF). The effect of wheat bran (WB) and rice husk (RH) was examined. The appropriate incubation period, moisture level, particle size and inoculum concentration was determined. Maximum yields of 159,520 and 21,760 U g −1 were achieved by employing WB and RH as substrates in 0.1 M phosphate buffer at pH 7 with 30% initial moisture content at 24 and 48 h. Particle size and inoculum concentration were found to be 1000 μm, 20% and 500 μm, 15% for WB and RH, respectively. Enzyme yield was 7.3-fold higher with WB medium compared with RH.

Equilibrium and thermodynamic studies on biosorption of Pb(II) onto Candida albicans biomass.

Biosorption of Pb(II) ions from aqueous solutions was studied in a batch system by using Candida albicans. The optimum conditions of biosorption were determined by investigating the initial metal ion concentration, contact time, temperature, biosorbent dose and pH. The extent of metal ion removed increased with increasing contact time, initial metal ion concentration and temperature. Biosorption equilibrium time was observed in 30min. The Freundlich and Langmuir adsorption models were used for the mathematical description of biosorption equilibrium and isotherm constants were also evaluated. The maximum biosorption capacity of Pb(II) on C. albicans was determined as 828.50+/-1.05, 831.26+/-1.30 and 833.33+/-1.12mgg(-1), respectively, at different temperatures (25, 35 and 45 degrees C). Biosorption showed pseudo second-order rate kinetics at different initial concentration of Pb(II) and different temperatures. The activation energy of the biosorption (Ea) was estimated as 59.04kJmol(-1) from Arrhenius equation. Using the equilibrium constant value obtained at different temperatures, the thermodynamic properties of the biosorption (DeltaG degrees , DeltaH degrees and DeltaS degrees ) were also determined. The results showed that biosorption of Pb(II) ions on C. albicans were endothermic and spontaneous. The optimum initial pH for Pb(II) was determined as pH 5.0. FTIR spectral analysis of Pb(II) adsorbed and unadsorbed C. albicans biomass was also discussed.

Production of Lipase by a Newly Isolated Bacillus coagulans Under Solid-State Fermentation Using Melon Wastes

SummaryAn extracellular lipase was produced by Bacillus coagulans by solid-state fermentation. Solid waste from melon was used as the basic nutrient source and was supplemented with olive oil. The highest lipase production (78,069 U/g) was achieved after 24h of cultivation with 1% olive oil enrichment. Enzyme had an optimal activity at 37°C and pH 7.0, and sodium dodecyl sulfate increased lipase activity. NH 4NO3 increased enzyme production, whereas organic nitrogen had no effect. The effect of the type of carbon sources on lipolytic enzyme production was also studied. The best results were obtained with starch and maltose (148,932 and 141,629 U/g, respectively), whereas a rather low enzyme activity was found in cultures grown on glucose and galactose (approx 118,769 and 123,622 U/g, respectively). Enzyme was inhibited with Mn+2 and Ni+2 by 68 and 74%, respectively. By contrast, Ca+2 enhanced enzyme production by 5%.

Production of Extracellular Alkaline α‐Amylase by Solid State Fermentation with a Newly Isolated Bacillus sp.

Abstract Production of alkaline α‐amylase employing our laboratory isolate, Bacillus sp., under solid state fermentation, was optimized. The effect of wheat bran and lentil husk was examined. Lentil husk exhibited the highest enzyme production. The appropriate incubation time, inoculum size, moisture level, and buffer solution level were determined. Maximum yields of 216,000 and 172,800 U/g were achieved by employing lentil husk and wheat bran as substrates in 0.1 M carbonate/bicarbonate buffer at pH 10.0 with 30% initial moisture level at 24 h. Inoculum size and buffer solution level were found to be 20% and 1:0.5 for two solid substrates.

Removal of methylene blue from aqueous solutions onto Bacillus subtilis: determination of kinetic and equilibrium parameters

AbstractIn the present study, Bacillus subtilis, a Gram-positive bacteria, was used in dried biomass form as biosorbent for removal of methylene blue (MB) from aqueous solutions. Batch adsorption tests were performed at different contact times, temperatures, pH, adsorbent doses, and initial dye concentration. The adsorption isotherms are described by means of the Langmuir and Freundlich isotherms. It was found that the Langmuir equation fit better than the Freundlich equation. Maximum biosorption capacity was found to be 169.49, 178.57, and 181.82 mg g−1 at 298, 308, and 318 K, respectively. The adsorption kinetics of MB could be described by the pseudo-second-order reaction model. The activation energy of the biosorption (Ea) was determined as 11.30 kJ mol−1 at initial concentration of 50 mg L−1. Free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated to predict the nature of adsorption. The estimated values for ΔG° were −21.22, −22.02, and −23.01 kJ mol−1 at 298, 308, ...

PRODUCTION AND CHARACTERIZATION OF PARTIALLY PURIFIED EXTRACELLULAR THERMOSTABLE α-AMYLASE BY Bacillus subtilis IN SUBMERGED FERMENTATION (SmF)

A Bacillus strain was isolated from soil samples from the campus area of Dicle University. Based on 16S ribosomal RNA sequencing, the microorganism was closely related to Bacillus subtilis. Effects of different culture medium, incubation time, carbon and nitrogen sources, and various starches, flours, and chemicals on α-amylase production were examined. Maximum enzyme production (7516 U/mL) was obtained in a basal medium A containing 0.05% Tween 40 in 24 h. Partially purified enzyme showed maximum activity at 60°C with an optimum pH of 6.0. The effects of 0.2% detergents (sodium dodecyl sulfate [SDS], CHAPS [3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate], and commercial detergent Omo Matic) on partially purified enzyme activity over a period of time (15–150 min) were examined and the order of inhibition effect from the most to the least was found as SDS > Omo Matic > CHAPS. Different metal ions inhibited α-amylase activity at low concentrations (1.5 mM). Co2+ was a mild inhibitor and Hg2+ and Cd2+ were potent inhibitors, whereas Ca2+ and Mg2+ increased the enzyme activity. At 20 mM, Ca2+ enhanced enzyme activity, and different Ca2+ concentrations (10–300 mM) were studied.

Dyeing of wool fibres with natural dyes: effect of proteolytic enzymes.

Abstract In spite of the widespread use of proteins (casein, peptone, etc.) and protein fragments as a substrate for the proteolytic enzymes, a substrate prepared from dyes that adsorb onto appropriate materials, such as wool and cotton, are also used for enzyme activity determination. In the point of view of this thought, it was our aim to develop the substrates which are easily and economically obtainable and also environmentally safer for the frequently used proteolytic enzymes, such as subtilisin carlsberg, trypsin, chymotrypsin, and protease type XVI and, if possible, to prepare the specific substrate at least for one of these enzymes. For this aim, wool was dyed with natural dyes such as juglone, lawsone, berberine, and quercetin. The optimum pH, incubation time, and agitation rate were determinated. The results indicate that, of all the tested enzymes on wool‐dye complex as an insoluble subtrate, the most appropriate complex was found to be wool‐lawsone complex.

Preconcentration with Bacillus subtilis–Immobilized Amberlite XAD-16: Determination of Cu2+ and Ni2+ in River, Soil, and Vegetable Samples

ABSTRACT Solid-phase extraction (SPE) method was developed for the preconcentration of Cu2+ and Ni2+ before their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Bacillus subtilis–immobilized Amberlite XAD-16 was used as biosorbent. Effects of critical parameters such as pH, flow rate of samples, amount of Amberlite XAD-16 and biosorbent, sample volume, eluent type, and volume and concentration of eluent on column preconcentration of Cu2+ and Ni2+ were optimized. Applicability of the method was validated through the analysis of the certified reference tea sample (NCS ZC73014). Sensitivity of ICP-OES was improved by 36.4-fold for Cu2+ and 38.0-fold for Ni2+ by SPE-ICP-OES method. Limit of quantitation (LOQ) was found to be 0.7 and 1.1 ng/ml for Cu2+ and Ni2+, respectively. Concentrations of Cu2+ and Ni2+ were determined by ICP-OES after application of developed method. Relative standard deviations (RSDs) were lower than 4.9% for Cu2+ and 7.9% for Ni2+. The Tigris River that irrigates a large agricultural part of Southeast Turkey is polluted by domestic and industrial wastes. Concentrations of Cu2+ and Ni2+ were determined in water, soil, and some edible vegetables as a biomonitor for heavy metal pollution.

Adsorption of Ni(II) from aqueous solution by Bacillus subtilis

Abstract This work reports the application of Bacillus subtilis as adsorbent for the removal of Ni(II) from aqueous solution. Batch experiments were conducted to study the effects of several parameters such as, contact time, initial concentration of adsorbate (25–200 mg L−1), temperature (298–318 K), and adsorbent dose (0.05–0.4 g) on Ni(II) adsorption. Equilibrium adsorption isotherms and kinetics were also investigated. The equilibrium experimental data were analyzed by Freundlich and Langmuir models. The kinetic data obtained with different initial concentration and temperature were analyzed using a pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. The results showed that this novel adsorbent had a high adsorption capacity, making it suitable for use in the treatment of Ni(II)-enriched wastewater.

OPTIMIZATION OF α-AMYLASE PRODUCTION BY Bacillus subtilis RSKK96: USING THE TAGUCHI EXPERIMENTAL DESIGN APPROACH

In this study, the Taguchi experimental design was applied to optimize the conditions for α-amylase production by Bacillus subtilis RSKK96, which was purchased from Refik Saydam Hifzissihha Industry (RSHM). Four factors, namely, carbon source, nitrogen source, amino acid, and fermentation time, each at four levels, were selected, and an orthogonal array layout of L16 (45) was performed. The model equation obtained was validated experimentally at maximum casein (1%), corn meal (1%), and glutamic acid (0.01%) concentrations with incubation time to 72 h in the presence of 1% inoculum density. Point prediction of the design showed that maximum α-amylase production of 503.26 U/mg was achieved under optimal experimental conditions.