Development of medium for enhanced production of glutaminase-free l-asparaginase from Pectobacterium carotovorum MTCC 1428

Biochemical characterization of extremozyme L-asparaginase from Pseudomonas sp. PCH199 for therapeutics

L-asparaginase (L-ASNase) from microbial sources is a commercially vital enzyme to treat acute lymphoblastic leukemia. However, the side effects associated with the commercial formulations of L-ASNases intrigued to explore for efficient and desired pharmacological enzymatic features. Here, we report the biochemical and cytotoxic evaluation of periplasmic L-ASNase of Pseudomonas sp. PCH199 isolated from the soil of Betula utilis, the Himalayan birch. L-ASNase production from wild-type PCH199 was enhanced by 2.2-fold using the Response Surface Methodology (RSM). Increased production of periplasmic L-ASNase was obtained using an optimized osmotic shock method followed by its purification. The purified L-ASNase was a monomer of 37.0 kDa with optimum activity at pH 8.5 and 60 ℃. It also showed thermostability retaining 100.0% (200 min) and 90.0% (70 min) of the activity at 37 and 50 ℃, respectively. The K_m and V_max values of the purified enzyme were 0.164 ± 0.009 mM and 54.78 ± 0.4 U/mg, respectively. L-ASNase was cytotoxic to the K562 blood cancer cell line (IC₅₀ value 0.309 U/mL) within 24 h resulting in apoptotic nuclear morphological changes as examined by DAPI staining. Therefore, the dynamic functionality in a wide range of pH and temperature and stability of PCH199 L-ASNase at 37 ℃ with cytotoxic potential proves to be pharmaceutically important for therapeutic application.

Nutritional Supplementation with Amino Acids on Bacterial Cellulose Production by Komagataeibacter intermedius: Effect Analysis and Application of Response Surface Methodology

Bacterial cellulose (BC) is a biopolymer mainly produced by acetic acid bacteria (AAB) that has several applications in the medical, pharmaceutical, and food industries. As other living organisms, AAB require sources of chemical elements and nutrients, which are essential for their multiplication and metabolite production. So, the knowledge of the nutritional needs of microorganisms that have important industrial applications is necessary for the nutrients to be supplied in the appropriate form and amount. Considering that the choice of different nutrients as nitrogen source can result in different metabolic effects, this work aimed to verify the effects of amino acid supplementation in the culture media for BC production by an AAB strain (Komagataeibacter intermedius V-05). For this, nineteen amino acids were tested, selected, and optimized through a Plackett and Burman factorial design and central composite design to determine the optimal concentrations of each required amino acid. Membranes produced under optimal conditions were characterized in relation to chemical structure and properties by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), and hydrophilic properties. Three amino acids had a significant positive effect and were required: aspartic acid (1.5 g L^-1), phenylalanine (1.5 g L^-1), and serine (3.0 g L^-1). Conversely, all sulfur and positively charged amino acids had a negative effect and reduced the production yield. After optimization and validation steps, a production level of 3.02 g L^-1 was achieved. Membranes produced from optimized media by this strain presented lower crystallinity index but greater thermal and hydrophilic properties than those produced from standard HS medium.

Fusarium sp. L-asparaginases: purification, characterization, and potential assessment as an antileukemic chemotherapeutic agent

Asparaginases important role in the treatment of leukemia. It is part of chemotherapy in the treatment of leukemia in the last three decades. L-Asparaginase is isolated from Fusarium sp. isolated from soil and purified using ammonium sulfate precipitation and Sephadex G 100. Characterization of the crude enzyme revealed it is a metalloprotease inhibited by EDTA. Hg²⁺, Cd²⁺, and Pb²⁺ also inhibited the enzyme. Mg²⁺, Zn²⁺, and Ca²⁺ activated L-asparaginase. Furthermore, kinetic studies of purified enzyme were carried out. V_max and K_m were 0.031 M and 454 U/mL, respectively. The optimum temperature was 30 °C and the optimum pH was 7. Concerning substrate specificity, gelatin and casein in addition to L-asparagine were tested. The enzyme was found to be nonspecific that could hydrolyze all tested substrates at different rates. The maximum enzyme activity was recorded in the case of L-asparagine, followed by casein and gelatin, respectively. The molecular weight of L-asparaginase was 22.5 kDa. The antileukemic cytotoxicity assay of the enzyme against RAW2674 leukemic cell lines by MTT viability test was estimated. The enzyme exhibited antileukemic activity with IC₅₀ of 50.1 UmL^-1. The current work presents additional information regarding the purification and characterization of the enzyme produced by Fusarium sp. and its evaluation as a potential antileukemic chemotherapeutic agent.

Optimization, Purification and Antitumor Activity of Kodamaea ohmeri ANOMY L-Asparaginase Isolated from Banana Peel

OBJECTIVE

L-Asparaginase is an important enzyme that converts L-asparagine to L-aspartate and ammonia. Microbial L-asparaginase has important applications as anticancer and food processing agents.

METHODS

This study reported the isolation, screening of a local yeast isolate from banana peel for L-asparaginase production using submerged fermentation, optimization of the production, purification, and anticancer assay of L-asparaginase. The yeast isolate was identified as Kodamaea ohmeri ANOMY based on the analysis of nuclear large subunit (26S) rDNA partial sequences. It was a promising L-asparaginase producer with a specific activity of 3059±193 U/mg in a non-optimized medium. The classical one-variable-at-a-time method was used to optimize the production medium components, and it was found that the elimination of K2HPO4 from the medium increased L-asparaginase specific activity (3100.90±180 U/mg).

RESULTS

Statistical optimization of L-asparaginase production was done using Plackett-Burman and Box-Behnken designs. The production medium for the maximum L-asparaginase specific activity (8500±578U/mg) was as follows (g/L): L-asparagine (7.50), NaNO3 (0.50), MgSO₄.7H₂O (0.80), KCl (0.80) associated with an incubation period of 5 days, inoculum size of 5.60 %, and pH (7.0). The optimization process increased L-asparaginase production by 2.78-fold compared to the non-optimized medium. L-Asparaginase was purified using ammonium sulphate precipitation followed by gel filtration on a Sephadex G-100 column. Its molecular weight was 66 KDa by SDS-PAGE analysis.

CONCLUSION

The cell morphology technique was used to evaluate the anticancer activity of L-asparaginase against three different cell lines. L-Asparaginase inhibited the growth of HepG-2, MCF-7, and HCT-116 cells at a concentration of 20, 50, and 60 μL, respectively.

L-asparaginase from Aspergillus oryzae spp.: effects of production process and biochemical parameters

L-asparaginases prevent the formation of acrylamide, a substance commonly found in foods subjected to heat and that also contains reducing sugars and L-asparagine. This work aimed to select a strain of Aspergillus spp. able to produce L-asparaginase and to optimize the fermentation parameters, the partial purification and biochemical characterization were also performed. The Aspergillus oryzae IOC 3999 was selected due to its greater enzymatic activity: 1443.57 U/mL of L-asparaginase after 48 h of fermentation. The optimized conditions allowed for an increase of 223% on the L-asparaginase production: 2.9% lactose, 2.9% L-asparagine and 0.7% hydrolyzed casein, 0.152% KH₂PO₄, 0.052% KCl and MgSO₄, 0.001% of CuNO₃.3H₂O, ZnSO₄.7H₂O and FeSO₄.7H₂O adjusted to pH 7.0; added a concentration of 5.05x10⁶ spores/mL at 30 °C for 100 rpm. A purification factor of 2.11 was found and the molecular mass was estimated at 20.8 kDa. The enzyme showed optimum activity at 60 °C and pH 5 and stability at 50 °C for 1 h. The enzyme presented desirable biochemical characteristics, mainly the acid pH stability, indicating that the enzyme would work well in food matrices due to the closeness of pH, meaning that it could be a potential option for use in the food industry.

Microbes Producing L-Asparaginase free of Glutaminase and Urease isolated from Extreme Locations of Antarctic Soil and Moss

L-Asparaginase (L-asparagine aminohydrolase, E.C. 3.5.1.1) has been proven to be competent in treating Acute Lymphoblastic Leukaemia (ALL), which is widely observed in paediatric and adult groups. Currently, clinical L-Asparaginase formulations are derived from bacterial sources such as Escherichia coli and Erwinia chrysanthemi. These formulations when administered to ALL patients lead to several immunological and hypersensitive reactions. Hence, additional purification steps are required to remove toxicity induced by the amalgamation of other enzymes like glutaminase and urease. Production of L-Asparaginase that is free of glutaminase and urease is a major area of research. In this paper, we report the screening and isolation of fungal species collected from the soil and mosses in the Schirmacher Hills, Dronning Maud Land, Antarctica, that produce L-Asparaginase free of glutaminase and urease. A total of 55 isolates were obtained from 33 environmental samples that were tested by conventional plate techniques using Phenol red and Bromothymol blue as indicators. Among the isolated fungi, 30 isolates showed L-Asparaginase free of glutaminase and urease. The L-Asparaginase producing strain Trichosporon asahii IBBLA1, which showed the highest zone index, was then optimized with a Taguchi design. Optimum enzyme activity of 20.57 U mL-1 was obtained at a temperature of 30 °C and pH of 7.0 after 60 hours. Our work suggests that isolation of fungi from extreme environments such as Antarctica may lead to an important advancement in therapeutic applications with fewer side effects.

Cationic reverse micellar based purification of recombinant glutaminase free L-asparaginase II of Bacillus subtilis WB800N from fermentation media

Reverse micellar extraction (RME), a liquid-liquid based separation is a versatile tool for protein purification. A statistical approach was employed for the purification of recombinant glutaminase free anti-cancerous enzyme viz., l-asparaginase II to evaluate the effects of RME in current study. The cationic system (CTAB/iso-octane/hexanol/butanol) was used in RME to optimize both forward and backward protein extraction efficiency. By adapting Taguchi's orthogonal array (OA), maximum forward extraction efficiency (FEE) of 86.98% with 84.82% enzyme activity recovery and 1.04 times purification fold achieved with the optimized parameters. Under the optimal levels, the back extraction efficiency (BEE) was observed to be 96.97% with 93.07% enzyme activity recovery and 1.38 times purification fold. Further, mass transfer kinetic studies of RME indicated the mass transfer coefficients of forward and backward extraction to be 0.049 min^-1 and 0.036 min^-1 respectively.

Combinatorial approach for screening and assessment of multiple therapeutic enzymes from marine isolatePseudomonas aeruginosaAR01

A simple and rapid screening of therapeutic enzymes from bacteria was conducted using functional- and sequence-based approach.

Production and structural modeling of a novel asparaginase in Yarrowia lipolytica

Asparaginase catalyzes the conversion of asparagine into aspartic acid and ammonia. The enzyme has various industrial applications and it is considered as an anticancer drug for treatment of certain leukemias. In the current study, production of asparaginase was investigated by Yarrowia lipolytica as well as optimized its production and determined its molecular characteristics by in silico analysis. Y. lipolytica DSM3286 produced 17.14 U/ml of asparaginase in flask culture. Optimization of asparaginase production was done by response surface methodology and the enzyme production increases up to 102.85 U/ml. The enzyme production reached 210 U/ml in a bioreactor which is 12-fold more than flask culture containing non-optimized medium. Asparaginase gene of Y. lipolytica was identified and isolated on the basis of comparison with asparaginase gene sequences of other microorganisms. The gene has 981 nucleotides and its protein has 326 amino acids. According to in silico analysis, the secondary structure of the enzyme is composed of 9 α-helixes and 11 β-sheets. Y. lipolytica produces type II asparaginase with high affinity for asparagine which is a suitable eukaryotic asparaginase for treatment of hematopoietic cancers. Hence, Y. lipolytica could be recommended as a new eukaryotic microbial source for the production of this important therapeutic enzyme.

Multi level statistical optimization of l-asparaginase from Bacillus subtilis VUVD001

Physical and chemical factors influencing the anti-leukemic l-asparaginase enzyme production by Bacillus subtilis VUVD001 were optimized using multi-stage optimization on the basis of preliminary experimental outcomes obtained by conventional one-factor-at-a-time approach using shake flasks. Process variables namely carbon, nitrogen sources, pH and temperature were taken into consideration during response surface methodology (RSM) optimization. The finest enzyme activity of 0.51 IUml^-1 obtained by OFAT method was enhanced by 3.2 folds using RSM optimization. Artificial neural network (ANN) modelling and genetic algorithm (GA) based optimizations were further carried out to improve the enzyme drug yield. Results were also validated by conducting experiments at optimum conditions determined by RSM and GA optimization methods. The novel bacterium yielded in 2.88 IUml^-1 of enzyme activity at optimum process variables determined by GA optimization, i.e., 0.5% glucose, 8.0% beef extract, 8.3 pH and 49.9 °C temperature. The study explored the optimized culture conditions for better yielding of anti-leukemic enzyme drug from a new bacterial source namely Bacillus subtilis VUVD001.

Influence of temperature and pH on the anammox process: A review and meta-analysis

The anammox (anaerobic ammonium oxidation) process was considered a very efficient and economic wastewater treatment technology immediately after its discovery in 1995, thus research in this field was intensified. The anammox process is characterised by a high temperature optimum and is very sensitive to both temperature and pH fluctuations. The process can also be inhibited by many factors, including by its substrates, i.e. nitrite and ammonium (or its unionised forms: free ammonia and free nitrous acid). This paper presents a comprehensive study of the most important and recent findings on the influence of two parameters that are crucial in wastewater treatment, i.e. temperature and pH. Because both parameters may influence the anammox process simultaneously, a meta-analysis was conducted of the data from the literature. Although meta-analysis is commonly used in medical research, mathematical analysis of the literature data has become an interesting and important step in the environmental sciences. This paper presents information on the influence of both temperature and pH on process efficiency and microbial composition. Additionally, the responses of different operating systems on both temperature and pH changes are described. Moreover, the role of both adaptation to changed conditions and of pH control as well as indicated areas of process operation are discussed.

Optimization of medium parameters by response surface methodology (RSM) for enhanced production of cutinase from Aspergillus sp. RL2Ct

Cutinases are hydrolytic enzymes which catalyzes esterification and trans-esterification reactions that make them highly potential industrial biocatalyst. In the present investigation microorganisms showing cutinase activity were isolated from plant samples. The strain showing maximum cutinase activity was identified by 18S rDNA sequencing as Aspergillus sp. RL2Ct and was selected for further studies. To achieve maximum enzyme production, the medium components affecting cutinase production were screened by Plackett-Burman followed by central composite design. The results obtained suggested that cutin, temperature and CaCl₂ have influenced the cutinase production significantly with very high confidence levels. Cutinase production was maximum (663 U/mg protein) when using cutin prepared from orange peel as sole source of carbon. An overall 4.33-fold increase in the production of cutinase was observed after optimization of culture conditions (including 2.5-fold increase using RSM) during 24 h of incubation. The production time of Aspergillus sp. RL2Ct cutinase is significantly lower than the most of the earlier reported cutinase-producing fungus.

Batch and fed-batch bioreactor studies for the enhanced production of glutaminase-free L-asparaginase from Pectobacterium carotovorum MTCC 1428

The effect of dissolved oxygen (DO) level and pH (controlled/uncontrolled) was first studied to enhance the production of novel glutaminase-free L-asparaginase by Pectobacterium carotovorum MTCC 1428 in a batch bioreactor. The optimum level of DO was found to be 20%. The production of L-asparaginase was found to be maximum when pH of the medium was maintained at 8.5 after 12 h of fermentation. Under these conditions, P. carotovorum produced 17.97 U/mL of L-asparaginase corresponding to the productivity of 1497.50 U/L/h. The production of L-asparaginase was studied in fed-batch bioreactor by feeding L-asparagine (essential substrate for production) and/or glucose (carbon source for growth) at the end of the reaction period of 12 h. The initial medium containing both L-asparagine and glucose in the batch mode and L-asparagine in the feeding stream was found to be the best combination for enhanced production of glutaminase-free L-asparaginase. Under this condition, the L-asparaginase production was increased to 38.8 U/mL, which corresponded to a productivity of 1615.8 U/L/h. The production and productivity were increased by 115.8% and 7.9%, respectively, both of which are higher than those obtained in the batch bioreactor experiments.

Industrial effluent as a substrate for glutaminase freel-asparaginase production from Pseudomonas plecoglossicida strain RS1; media optimization, enzyme purification and its characterization

Glutaminase freel-asparaginase production byPseudomonas plecoglossicidaRS1 using industrial effluent as a substrate: media optimization, enzyme purification and its characterization.

Optimization of cultural conditions using response surface methodology versus artificial neural network and modeling of L-glutaminase production by Bacillus cereus MTCC 1305

Response surface methodology and artificial neural network were used to optimize cultural conditions of L-glutaminase production from Bacillus cereus MTCC 1305. ANN model was superior to RSM model with higher value of coefficient of determination (99.97ANN>97.78RSM), predicted distribution coefficient (0.9992ANN>0.896RSM) and lower value of absolute average deviation (1.17%ANN<18.47%RSM). Optimum cultural conditions predicted by ANN were pH (7.5), fermentation time (40 h), temperature (34°C), inoculum size (2%), inoculum age (10 h) and agitation speed (175 rpm) with a maximum predicted production of L-glutaminase 666.97 U/l which was close to experimental production of L-glutaminase 667.23 U/l at simulated optimum cultural condition. The production of L-glutaminase was enhanced by 1.58-fold after optimization of cultural conditions. Simple kinetic models were developed using Logistic equation for cell growth, Luedeking Piret equation for L-glutaminase production and modified Luedeking Piret equation for glucose utilization indicating that L-glutaminase fermentation is non growth associated process.

Purification and characterization of glutaminase-free L-asparaginase from Pectobacterium carotovorum MTCC 1428

An intracellular glutaminase-free L-asparaginase from Pectobacterium carotovorum MTCC 1428 was isolated to apparent homogeneity. The homotetramer enzyme has a molecular mass of 144.4 kDa (MALDI-TOF MS) and an isoelectric point of approximately 8.4. The enzyme is very specific for its natural substrate, L-asparagine. The activity of L-asparaginase is activated by mono cations and various effectors including Na+, K+, L-cystine, L-histidine, glutathione and 2-mercaptoethanol whereas it is moderately inhibited by various divalent cations and thiol group blocking reagents. Kinetic parameters, Km, Vmax and kcat of purified L-asparaginase from P. carotovorum MTCC 1428 were found to be 0.657 mM, 4.45 U μg(-1) and 2.751×10(3) s(-1), respectively. Optimum pH of purified L-asparaginase for the hydrolysis of L-asparagine was in the range of 8.0-10.0, and its optimum temperature was found to be 40 °C. The purified L-asparaginase has no partial glutaminase activity, which can reduce the possibility of side effects during the course of anti-cancer therapy.