Aspergillus awamori MK788209 cellulase: production, statistical optimization, pea peels saccharification and textile applications

BACKGROUND

The demand for low-cost cellulolytic enzyme synthesis is rising in the enzyme market. This work aims to produce cellulase by utilizing various agricultural wastes and investigating the use of enzyme in saccharification and textile industries.

RESULTS

Solid state fermentation (SSF) was applied to produce industrial enzymes, particularly cellulase, through utilizing Molokhia (Corchorus olitorius) stems by Aspergillus awamori MK788209 isolate. Two stages of statistical factorial designs Plackett-Burman (PB) and Central Composite Design (CCD) were applied to enhance the A. awamori MK788209 cellulase production from Molokhia stems (MS). The fold increase of enzyme production by PB followed by CCD was 2.51 and 4.86, respectively. Additionally, the A. awamori MK788209 culture filtrate was highly effective in saccharifying various agricultural wastes, particularly pea peels (PP) (yielding 98.33 mg reducing sugar/ml), due to its richness in cellulase, laccase, xylanase, pectinase, and amylase. By optimizing the three main variables; pea peel weight, culture filtrate volume added, and saccharification time by CCD, the sugar recovery from PP was enhanced, leading to a 3.44-fold increase in reducing sugar recovery (338 mg reducing sugar /ml). Furthermore, the A. awamori MK788209 culture filtrate showed high efficacy in textile applications, enhancing the roughness, weight loss, white index, and printing capability of treated cotton fabrics.

CONCLUSIONS

A. Awamori MK788209 produced cellulase which was effective in PP saccharification. The enzyme was also capable of enhancing cotton fabric properties.

A promising microbial α-amylase production, and purification from Bacillus cereus and its assessment as antibiofilm agent against Pseudomonas aeruginosa pathogen

BACKGROUND AND AIM

The purpose of the current study is to isolate a heavily amylase-producing bacteria of the genus Bacillus from soil samples, optimize the production of the enzyme, purify it, and evaluate its activity against biofilm-producing bacteria. A total of 12 soil samples were collected and screened for promising Bacillus species with good amylolytic activity. Isolation was done by serial dilution and plating technique and amylolytic activity was determined by starch agar plate method. Among the 12 Bacillus isolates recovered from soil samples, 7 showed positive α-amylase production. The best isolate that recorded the greatest amylolytic activity was selected for further studies. This isolate was identified by 16S rRNA sequencing as Bacillus cereus and registered under gene bank accession number OP811897. Furthermore, the α-amylase enzyme was produced by a submerged fermentation technique using best production media and partially purified by ammonium sulfate and chilled ethanol and molecular weight had been determined by SDS-PAGE gel electrophoresis. The production of α-amylase was optimized experimentally by one-factor at a time protocol and statistically by Plackett-Burman design as well as RSM CCD design. Data obtained from OFAT and CCD revealed that α-amylase activities were 1.5- and twofold respectively higher as compared to un-optimized conditions. The most significant factors had been identified and optimized by CCD design.

RESULTS

Among the eleven independent variables tested by PBD, glucose, peptone, (NH4)₂SO4, and Mg SO₄ were the most significant parameters for α-amylase production with an actual yield of 250U/ml. The best physical parameters affecting the enzyme production were incubation time at 35 °C, and pH 5.5 for 48 h. The partially purified enzyme with 60% ammonium sulphate saturation with 1.38- fold purification showed good stability characteristics at a storage temperature of 4 °C and pH up to 8.5 for 21 days. Antibiofilm activity of purified α-amylase was determined against Pseudomonas aeruginosa (ATCC 35659) by spectrophotometric analysis and CLSM microscopic analysis. Results demonstrated biofilm inhibition by 84% of the formed Pseudomonas biofilm using a microtiter plate assay and thickness inhibition activity by 83% with live/Dead cells percentage of 17%/83% using CLSM protocol.

CONCLUSIONS

A highly stable purified α-amylase from B. cereus showed promising antibiofilm activity against one of the clinically important biofilm-forming MDR organisms that could be used as a cost-effective tool in pharmaceutical industries.

Statistical optimization of enzyme cocktail production using Jew's mallow stalks residues by a new isolate Aspergillus flavus B2 via statistical strategy and enzymes characterization

This study investigates the production of the enzyme cocktail by the isolated fungi Aspergillus flavus B2 (GenBank accession number OL655454) using agricultural and industrial (AI) residues as the sole substrate. Of all the AI residues tested, Jew's mallow stalk was the best inducer substrate for enzyme cocktail production without adding any nutrients. Statistical optimization using Response Surface Methodology enhanced the production by 5.45, 5.20, and 3.34-fold, respectively for pectinase, xylanase, and CMCase. Optimum temperature, activation energy (E_a), and activation energy for denaturation (E_d) were determined. Michaelis constant (K_m) for CMCase, xylanase, and pectinase enzyme was 1.82, 1.23, and 1.05mg/mL, respectively. Maximum reaction rate (V_max) was 4.67, 5.29, and 17.13U/mL, respectively for CMCase, xylanase, and pectinase. Thermal stability revealed that pectinase, CMCase, and xylanase enzymes retained 64.7, 61.8, and 53.2% residual activities after incubation for 1h at 50 °C. Half-life time (t_0.5) of pectinase, CMCase, and xylanase at 50 °C were 189.38, 129.8, and 127.89min, respectively. Thermodynamics of the produced enzymes enthalpy (ΔH⁎_d), free energy (ΔG⁎_d), and entropy (ΔS⁎_d) were determined at 40, 50, and 60°C. In the presence of EDTA (5mM), CMCase, xylanase, and pectinase retained 69.5, 66.2, and 41.2%, respectively of their activity. This work is significant for the valorization of AI residues and the production of value-added products.

Purification, amino acid sequence, and characterization of bacteriocin GA15, a novel class IIa bacteriocin secreted by Lactiplantibacillus plantarum GCNRC_GA15

The bacteriocins produced by lactic acid bacteria (LAB) are attracting attention due to their promising applications in food and pharmaceuticals fields. Hence, a LAB strain, GCNRC_GA15, was isolated from Egyptian goat cheese, and molecularly identified as Lactiplantibacillus plantarum. This strain showed a wide antimicrobial spectrum, which was found to be of proteineous nature, suggesting that L. plantarum GCNRC_GA15 is a bacteriocin-producer. This bacteriocin (bacteriocin GA15) was partially purified using cation exchange, and hydrophobic interaction chromatography. Tricine SDS-PAGE analysis for the fraction showing bacteriocin activity has estimated the molecular mass to be 4369 Da. Furthermore, amino acid sequencing of this peptide has detected 34 amino acids, and comparing its amino acid sequence with those of some pediocin-like bacteriocins revealed that bacteriocin GA15 has the conserved sequence (YYGNGV/L) in its N-terminal region which identified bacteriocin GA15 as a pediocin-like bacteriocin. Bacteriocin GA15 showed good heat and pH stabilities, and its activity was enhanced after treatment with Tween 80 or Triton X-100. Bacteriocin production medium was statistically optimized using the Plackett-Burman and Central Composite designs. As a result, bacteriocin production increased from 800 to 12,800 AU/ml using the optimized medium in comparison with result recorded for the un-optimized medium.

The ancient koji mold (Aspergillus oryzae) as a modern biotechnological tool

Aspergillus oryzae (A. oryzae) is a filamentous micro-fungus that is used from centuries in fermentation of different foods in many countries all over the world. This valuable fungus is also a rich source of many bioactive secondary metabolites. Moreover, A. oryzae has a prestigious secretory system that allows it to secrete high concentrations of proteins into its culturing medium, which support its use as biotechnological tool in veterinary, food, pharmaceutical, and industrial fields. This review aims to highlight the significance of this valuable fungus in food industry, showing its generosity in production of nutritional and bioactive metabolites that enrich food fermented by it. Also, using A. oryzae as a biotechnological tool in the field of enzymes production was described. Furthermore, domestication, functional genomics, and contributions of A. oryzae in functional production of human pharmaceutical proteins were presented. Finally, future prospects in order to get more benefits from A. oryzae were discussed.

Characterization of Aspergillus niger MK981235 xylanase with extraction of anti-hepatotoxic, antioxidant, hypocholesterolemic and prebiotic Corchorus olitorius stems xylooligosaccharides

The object of this study was to utilize agro-industrial waste Corchorus olitorius stems (molokhia stems, MS) as substrate, for Aspergillus niger MK981235 xylanase production and as source of biologically active xylooligosaccharides (XOS). This study succeeded in utilization of Aspergillus niger MK981235 xylanase under different saccharification conditions designed by central composite design (CCD) for extraction of 15 biologically active XOS (anti-hepatotoxic, antioxidant, hypocholesterolemic and prebiotic) with different monosaccharides constituents composition and percent. A. niger MK981235 xylanase showed the highest activity 6.60 U·ml^-1 at 50 °C with 1.5% xylan. The kinetics included K_m and V_max were determined to be 6.67 mg·ml^-1 and 20 μmol·ml^-1·min^-1, respectively. Moreover, A. niger MK981235 xylanase thermodynamics E_a (activation energy) and E_d (activation energy of denaturation) were determined to be 21.95 and 39.51 KJ·mol^-1, respectively. The highest prebiotic effect (growth promation) was exerted by the central MS XOS on Lactobacillus plantarum and Lactobacillus rhamnosus (125 and 135.3%, respectively). Also, the central MS XOS, exerted the highest cholesterol reduction and antioxidant activities 74.7 and 92%, respectively, showed remarkable in vivo protective role against the hepatic toxicity of lithium carbonate evaluated by changes in body weight, liver function markers (AST, ALT, Alb, total bilirubin) and tissue makers (MDA and GSH).

Physiochemical, kinetic and thermodynamic studies on Aspergillus wewitschiae MN056175 inulinase with extraction of prebiotic and antioxidant Cynara scolymus leaves fructo-oligosaccharides

Utilization of agricultural wastes as cheap natural resources for production of bioactive products is currently attracting global attention. For this purpose, this study focused on isolation of Aspergillus wewitschiae MN056175 as promising producer of inulinase, then investigating physiochemical, kinetics and thermodynamics of the obtained inulinase, and its ability to extract bioactive fructo-oligosaccharides (FOS) from Cynara scolymus leaves (artichoke leaves, AL). A. wewitschiae MN056175 inulinase gave the maximum activity at temperature 60 °C and inulin concentration 1%. The kinetics including K_m and V_max were determined to be 105.26 mg·ml^-1 and 83.33 μmol·ml^-1·min^-1, respectively. The thermodynamics including, E_a (activation energy) and E_d (activation energy for denaturation) were determined to be 21.82 and 73.21 kJ·mol^-1, K_d, T_1/2, D-value, ΔH°, ΔG° and ΔS° at 40, 50 and 60 °C which indicated the stability of A. wewitschiae MN056175 inulinase. Moreover, this inulinase was capable of hydrolyzing Cynara scolymus leaves into reducing sugar and 15 FOS with different DP, total carbohydrate, and protein content under different conditions designed by central composite design (CCD). The 15 AL FOS showed different high antioxidant and prebiotic activities. Central FOS with probiotic bacteria exhibited significant antimicrobial activity against tested gram positive bacteria in a way higher than those recorded against gram negative bacteria.

Thermodynamics enhancement of Alternaria tenuissima KM651985 laccase by covalent coupling to polysaccharides and its applications

This study full filed in enhancement of catalytic, thermodynamics and storage stability of Alternaria tenuissima KM651985 laccase by conjugation to sodium periodate oxidized starch. The starch conjugated A. tenuissima KM651985 laccase was active over a wide range of temperatures and pHs with the highest activity at 60 °C and 4, respectively. The thermal stability of conjugated A. tenuissima KM651985 laccase was indicated by, high T_1/2 values (half life) 1076.16, 382.42 and 191.23 min at 50, 60 and 70 °C, respectively, low K_d (denaturation rate constant) 6.44 × 10^-4, 18.13 × 10^-4 and 36.25 × 10^-4 min^-1 at the same temperatures, high D-values (decimal reduction time) 3575.56, 1270.61 and 635.38 min at the same temperatures. Also, the thermal stability of conjugated A. tenuissima KM651985 laccase was emphasized by high ΔH_d (enthalpy), high ΔG_d (free energy) and low ΔS_d (entropy). The conjugated A. tenuissima KM651985 laccase showed high effectiveness in dyes decolorization of Remazol Brilliant Blue R (RBBR) and Malachite Green (MG). Moreover, the addition of conjugated A. tenuissima KM651985 laccase with hemicellulolytic enzymes cocktail improved the saccharification of corn cobs, rice straw, corn cobs leaves and water hyacinth with the highest reducing sugar production 847.44 ± 19.17 mg from corn cops.

Improvement of Aspergillus flavus saponin hydrolase thermal stability and productivity via immobilization on a novel carrier based on sugarcane bagasse

Soyasapogenol B (SB) is known to have many biological activities such as hepatoprotective, anti-inflammatory, anti-mutagenic, antiviral and anticancer activities. Enzymatic conversion of soyasaponins to SB was carried out using saponin hydrolase (SH) extracted from Aspergillus flavus. The partially purified enzyme was immobilized on different carriers by physical adsorption, covalent binding or entrapment. Among the investigated carriers, Eupergit C and sugarcane bagasse (SCB) activated by DIC and NHS were the most suitable two carriers for immobilization (the immobilized forms recovered 46.5 and 37.1% of the loaded enzyme activity, respectively). Under optimized immobilization conditions, immobilized SH on Eupergit C and on activated SBC recovered 87.7 and 83.3% of its original activity, respectively. Compared to free SH, immobilized SH on Eupergit C and on activated SCB showed higher optimum pH, activation energy, half-lives and lower deactivation constant rate. Also, their SB productivities were improved by 2.3- and 2.2-folds compared to free SH (87.7 and 83.3 vs. 37.5%, respectively). Hence, being SCB more sustainable and an inexpensive material, it can be considered a good alternative to Eupergit C as a support for SH immobilization. SH immobilization on industrially applicable and inexpensive carrier is necessary to improve SB yield and reduce its production cost. The chemical structure of SCB and the resulting cellulose derivatives were studied by ATR-IR spectroscopy. The thermal analysis technique was used to study the chemical treatment of SCB and coupling with the enzyme. This technique confirmed the removal of lignin and hemicellulose by chemical treatment of SCB.

Purification, physicochemical and thermodynamic studies of antifungal chitinase with production of bioactive chitosan-oligosaccharide from newly isolated Aspergillus griseoaurantiacus KX010988

In our search for chitinase and chitosanase producer from unconventional sources, the marine-derived fungus Aspergillus griseoaurantiacus KX010988 was obviously the best producer of the highest chitinase and chitosanase activities by solid state fermentation of potato shells. Chitinase was purified in three steps involving ammonium sulphate precipitation, DEAE-cellulose ion-exchange chromatography and Sephacryl S-300 gel chromatography. 12.55 fold increase in purity with a recovery of 17.6 was obtained. The molecular mass of the purified chitinase was found to be 130kDa. It was optimally active at pH 4.5 and 40°C. K_m and V_max values were 0.22mgmL^-1 and 19.6μmolemin^-1mg^-1 respectively. Mn²⁺ and Zn²⁺ ions lead to increased chitinase activity. While Fe²⁺and Cu²⁺ions strongly inhibited the chitinase activity. The thermodynamics of pure chitinase including activation energy for thermal denaturation (E_a,d), change of free energy (ΔG_d), enthalpy(ΔH_d), entropy(ΔS_d) and half life values (T_1/2) at 40, 50 and 60°C were determined. Chitinase showed antifungal activity against pathogenic fungus Fusarium solani. Chitosanase was partially purified by acetone precipitation (50-75%) v/v concentration. The hydrolytic products of moderate molecular weight of chitosan by chitosanase were analyzed by thin layer chromatography (TLC) after 12 and 24h respectively. Chitosan-oligosaccharides showed good antibacterial and antioxidant activities.

Hepatic succinic dehydrogenase in marasmic Egyptian infants

In a group of 15 marasmic infants, the activity of the liver enzyme "succinic dehydrogenase" (SDH) was studied. This was compared with the activity of that enzyme in the livers of 10 normal infants, taken as controls. Histologic changes were found in only one third of the marasmic cases studied while abnormal liver functions were noted in two thirds of them and diminished SDH activity in all of them. The presence of diminished activity of SDH in 100% of the cases may explain the discrepancy between the occurrence of histologic hepatic changes in about 33% only and the occurrence of disturbed liver functions in about 66% of the cases.

Histopathology and histochemistry of the kidney in marasmic Egyptian children

Percutaneous renal biopsy was done in 15 infants and children with third degree marasmus and in five normal controls. All the cases were free from infection. Histopathological changes as shown in sections stained with hematoxylin and cosin include patchy areas of colloid degeneration and thickening of the walls of some blood vessels in 10 out of 15 marasmic cases. Some proximal convoluted tubules appeared small or atrophic, others are somewhat dilated with decreased thickness of their walls, while others showed necrotic changes. The distal convoluted tubules in the medulla appeared vacuolated and distorted. The activity of the enzyme succinic dehydrogenase (SDH) is markedly inhibited especially in the distal convoluted tubules in all the patients studied.

Intrinsic innervation of the urinary bladder of kangaroo and albino rats

A comparative study of the intrinsic innervation in desert rodents (kangaroo rats) and others (albino rats) was carried out in an attempt to understand the functional anatomy of the bladder in these animals which are known to sustain severe water restraint. The bladder of the albino rat was innervated by predominantly thin nerves, more numerous beaded endings and few ganglia. That of the kangaroo rat had more numerous thick nerves (pre-ganglionic), large verve trunks, and ganglia which were extensively distributed in the wall. These findings indicate that the bladder of the albino rat depends mainly on the intrinsic innervation and facilatory micturition reflexes, while that of the kangaroo rat is intrinsically regulated, depending on a short neuron system. It was concluded that all the structural differences found might be essential for constant urine retention.