The effect of different substrates on chitinase activity from Bacillus sp. WS4F

One of the roles of chitinase is as an antifungal which is widely used as a biocontrol agent for plant diseases caused by pathogenic fungi. Bacillus sp. WS4F has chitinase activity which can inhibit the growth of Ganoderma boninense, a fungus that attacks oil palm and causes basal stem rot (BSR). This study aims to investigate the effect of different substrates on the activity of the chitinase from Bacillus sp. WS4F. Two kinds of substrates i.e. chitin flakes and shrimp shells were used in this study. Enzyme activity of chitinase was analyzed after partial purification of enzyme was performed using ammonium sulfate precipitation followed by dialysis. The highest activity of chitinase was achieved by the substrate using shrimp shells. The ammonium sulfate precipitation (60-80% saturation) 0.0949 U/mL for activity enzyme and 0.2639 mg/mL for protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the enzyme showed a molecular weight of 64.389 kDa.

Extraction and Purification of R-Phycoerythrin Alpha Subunit from the Marine Red Algae Pyropia Yezoensis and Its Biological Activities

Phycoerythrin is a major light-harvesting pigment of red algae and cyanobacteria that is widely used as a fluorescent probe or as a colorant in the food and cosmetic industries. In this study, phycoerythrin was extracted from the red algae Pyropia yezoensis and purified by ammonium sulfate precipitation and various chromatography methods. The purified phycoerythrin was analyzed by UV-visible and fluorescence spectroscopy. The isolated pigment had the typical spectrum of R-phycoerythrin, with a trimmer state with absorbance maxima at 497, 536, and 565 nm. It was further purified and identified by LC-MS/MS and Mascot search. It showed a 100% sequence similarity with the R-phycoerythrin alpha subunit of Pyropia yezoensis. The molecular mass was 17.97 kDa. The antioxidant activity of the purified R-phycoerythrin alpha subunit was analyzed. It showed significant antioxidant activity in ABTS and FRAP assays and had significant cytotoxicity against HepG2 cells.

Purification and immobilization of L-asparaginase from Citrobacter freundii EGY-NE1

L-asparaginase is used as an antileukemic drug and as a food additive to reduce the risk of acrylamide formation. New L-asparaginases are required to reduce costs and avoid clinical side effects. Citrobacter freundii EGY-NE1represents a potential source of new L-asparaginase. We purified extracellular L-asparaginase from Citrobacter freundii EGY-NE1 (through ammonium sulfate precipitation, dialysis, Sephadex-G50 and DEAE-cellulose columns) to 5.83 fold and 25.76 % recovery. The purified L-asparaginase was a low molecular weight enzyme of 19 kDa. It was optimally active at 37 ˚C, pH 8 and 40 mM asparagine. The Km and Vmax of the enzyme were 0.0179 M and 2.66 U/ml, respectively. Ca2+, Mg2+, K+ and Ba+ 2 activated the enzyme, while Na+, Zn+ 2, EDTA, azide, tartrate and HgCl2 inhibited it. The crude and purified enzymes were immobilized by encapsulation in Ca-alginate; this improved their stability and reusability. The entrapped L-asparaginases on Ca-alginate were examined by scanning electron microscope; their protein diameters ranged from 42.17 to 47.37 nm and from 46.78 to 71.97 nm for the immobilized crude and purified enzymes, respectively. Both the immobilized enzymes kept their maximal activity for 10 minutes at 40 ˚C. After the 5th cycle of repeated use, the immobilized purified and crude enzymes kept 91% and 89 % of their activities, respectively.

Production and Purification of the Endoglucanase Enzyme from Local Isolate Aspergillus fumigatus HBF356

In this study, endoglucanase (EG) from local isolate Aspergillus fumigatus HBF356 was produced and purified using ammonium sulfate precipitation, gel filtration chromatography, and ion-exchange chromatography. The molecular weight of the pure EG was determined as 95 kDa. The optimum pH of the purified EG was determined as 4.0 and the optimum temperature as 60°C. It has been observed that the enzyme had a very high thermostability and preserved 75.8% of its activity after 240 hours of incubation at 50 °C. At the same time, the effect of veterinary drugs (gentamicin sulfate and enrofloxacin) on the activity of the EG was investigated. The activity of EG was inhibited by gentamicin sulfate while that was activated with enrofloxacin. The results of this study can give information about the potential of EG from Aspergillus fumigatus HBF356 using as a feed additive and its interaction with animal drugs.

A Broad-Specificity Chitinase from Penicillium oxalicum k10 Exhibits Antifungal Activity and Biodegradation Properties of Chitin

Penicillium oxalicum k10 isolated from soil revealed the hydrolyzing ability of shrimp chitin and antifungal activity against Sclerotinia sclerotiorum. The k10 chitinase was produced from a powder chitin-containing medium and purified by ammonium sulfate precipitation and column chromatography. The purified chitinase showed maximal activity toward colloidal chitin at pH 5 and 40 °C. The enzymatic activity was enhanced by potassium and zinc, and it was inhibited by silver, iron, and copper. The chitinase could convert colloidal chitin to N-acetylglucosamine (GlcNAc), (GlcNAc)2, and (GlcNAc)3, showing that this enzyme had endocleavage and exocleavage activities. In addition, the chitinase prevented the mycelial growth of the phytopathogenic fungi S. sclerotiorum and Mucor circinelloides. These results indicate that k10 is a potential candidate for producing chitinase that could be useful for generating chitooligosaccharides from chitinous waste and functions as a fungicide.

Ethanol treatment for sterilization, concentration, and stabilization of a biodegradable plastic–degrading enzyme from Pseudozyma antarctica culture supernatant

Biodegradable plastics must be sufficiently stable to maintain functionality during use but need to be able to degrade rapidly after use. We previously reported that treatment with an enzyme named PaE, secreted by the basidiomycete yeast Pseudozyma antarctica can speed up this degradation. To facilitate the production of large quantities of PaE, here, we aimed to elucidate the optimal conditions of ethanol treatment for sterilization of the culture supernatant and for concentration and stabilization of PaE. The results showed that Pseudozyma antarctica completely lost its proliferating ability when incubated in ≥20% (v/v) ethanol. When the ethanol concentration was raised to 90% (v/v), PaE formed a precipitate; however, its activity was restored completely when the precipitate was dissolved in water. To reduce ethanol use, PaE was successfully concentrated and recovered by sequential ammonium sulfate precipitation and ethanol precipitation steps. Over 90% of the activity in the original culture supernatant was recovered and the specific activity was increased 3.4-fold. By preparing the enzyme solution at a final concentration of 20% (v/v) ethanol, about 60% of the initial activity was maintained at ambient temperature for over 6 months without growth of microbes. We conclude that ethanol treatment is effective for sterilization, concentration, and stabilization of PaE, and that concentrating PaE by sequential ammonium sulfate precipitation and ethanol precipitation substantially increases the PaE purity and decreases ethanol use.

Bioprocess development for enhanced endoglucanase production by newly isolated bacteria, purification, characterization and in-vitro efficacy as anti-biofilm of Pseudomonas aeruginosa

Endoglucanase producing bacteria were isolated from Egyptian soils and the most active bacterial strain was identified as Bacillus subtilis strain Fatma/1. Plackett–Burman statistical design was carried out to assess the effect of seven process variables on endoglucanase production. Carboxymethyl cellulose (CMC), yeast extract and peptone were the most significant variables that enhanced the endoglucanase production and thus were selected for further optimization using face-centered central composite design. The highest yield of endoglucanase (32.37 U/mL) was obtained in run no. 9, using 18 g/L CMC, 8 g/L peptone, 7 g/L yeast extract and 0.1 g/L FeSO4.7H2O. The optimized medium showed about eightfold increase in endoglucanase production compared to the unoptimized medium. The produced crude enzyme was further purified by ammonium sulfate precipitation, then DEAE-Sepharose CL6B column. The purified enzyme was shown to have a molecular weight of 37 kDa. The enzyme showed maximum activity at pH 8.0, temperature of 50 °C, incubation time of 60 min. The half-life time (T1/2) was 139.53 min at 50 °C, while being 82.67 min at 60 °C. Endoglucanase at concentration of 12 U/mL effectively removed 84.61% of biofilm matrix of Pseudomonas aeruginosa with marked reduction in carbohydrate content of the biofilm from 63.4 to 7.9 μg.

Production of the HBc Protein from Different HBV Genotypes in E. coli. Use of Reassociated HBc VLPs for Packaging of ss- and dsRNA

The core proteins (HBc) of the hepatitis B virus (HBV) genotypes A, B, C, D, E, F, and G were cloned and expressed in Escherichia coli (E. coli), and HBc-formed virus-like particles (VLPs) were purified with ammonium sulfate precipitation, gel filtration, and ion exchange chromatography (IEX). The best VLP yield was found for the HBc of the HBV genotypes D and G. For the HBc of the HBV genotypes D, F, and G, the possibility of dissociation and reassociation maintaining the native HBc structure was demonstrated. Single-stranded (ss) and double-stranded (ds) ribonucleic acid (RNA) was successfully packed into HBc VLPs for the HBV genotypes D and G.

A set of simple methods for detection and extraction of laminarinase

A carefully designed ammonium sulfate precipitation will simplify extraction of proteins and is considered to be a gold standard among various precipitation methods. Therefore, optimization of ammonium sulfate precipitation can be an important functional step in protein purification. The presence of high amounts of ammonium sulphate precludes direct detection of many enzymatically active proteins including reducing sugar assays (e.g. Nelson-Somogyi, Reissig and 3,5-dinitrosalicylic acid methods) for assessing carbohydrases (e.g. laminarinase (β (1–3)-glucanohydrolase), cellulases and chitinases). In this study, a simple method was developed using laminarin infused agarose plate for the direct analysis of the ammonium sulphate precipitates from Streptomyces rimosus AFM-1. The developed method is simple and convenient that can give accurate results even in presence of ammonium sulfate in the crude precipitates. Laminarin is a translucent substrate requiring the use of a stain to visualize the zones of hydrolysis in a plate assay. A very low-cost and locally available fluorescent optical fabric brightener Tinopal CBS-X has been used as a stain to detect the zones of hydrolysis. We also report simple methods to prepare colloidal chitin and cell free supernatant in this manuscript.

Lipase from Rhizopus oryzae R1: in-depth characterization, immobilization, and evaluation in biodiesel production

Background Rhizopus species is among the most well-known lipase producers, and its enzyme is suitable for use in many industrial applications. Our research focuses on the production of lipase utilizing waste besides evaluating its applications. Results An extracellular lipase was partially purified from the culture broth of Rhizopus oryzae R1 isolate to apparent homogeneity using ammonium sulfate precipitation followed by desalting via dialysis. The partially purified enzyme was non-specific lipase and the utmost activity was recorded at pH 6, 40 °C with high stability for 30 min. The constants Km and Vmax, calculated from the Lineweaver-Burk plot, are 0.3 mg/mL and 208.3 U/mL, respectively. Monovalent metal ions such as Na+ (1 and 5 mM) and K+ (5 mM) were promoters of the lipase to enhance its activity with 110, 105.5, and 106.5%, respectively. Chitosan was used as a perfect support for immobilization via both adsorption and cross-linking in which the latter method attained immobilization efficiency of 99.1% and reusability of 12 cycles. The partially purified enzyme proved its ability in forming methyl oleate (biodiesel) through the esterification of oleic acid and transesterification of olive oil. Conclusion The partially purified and immobilized lipase from Rhizopus oryzae R1 approved excellent efficiency, reusability, and a remarkable role in detergents and biodiesel production.