Characteristics and thermodynamics of α-amylase from thermophilic actinobacterium, Laceyella sacchari TSI-2

Valorization of Cocoa and Peach-Palm Wastes for the Production of Amylases by Pleurotus pulmonarius CCB19 and Its Application as an Additive in Commercial Detergents

In the context of agribusiness, the agricultural and livestock sectors generate a considerable quantity of waste on a daily basis. Solid-state fermentation (SSF) represents a potential alternative for mitigating the adverse effects of residue accumulation and for producing high-value products such as enzymes. Pleurotus pulmonarius is capable of producing a number of commercial enzymes, including amylases. Accordingly, the present study sought to produce, characterize, and apply amylases obtained from solid-state fermentation of cocoa and peach-palm waste by the fungus Pleurotus pulmonarius CCB19. The highest amylase production by P. pulmonarius was observed after 3 days of solid-state fermentation of the cocoa shells, with an activity of 83.90 U/gds. The physicochemical characterization of the crude amylase using the artificial neural network (ANN) revealed that the highest activity was observed at pH 9 and a temperature of 20 °C (120.7 U/gds). Furthermore, the amylase demonstrated stability in the majority of the tested conditions, maintaining up to 80% of its residual activity for up to 120 min of incubation. With regard to the impact of ions and reagents on enzymatic activity, a positive effect was observed in the presence of Co+ ions at concentrations of 1 and 5 mM, whereas Cu+ ions at 5 mM demonstrated an inhibitory effect. The addition of SDS and EDTA reagents did not affect the observed activity. Furthermore, the extract was tested in commercial detergent formulations and demonstrated enhanced compatibility (110%) and efficacy (270% with boiled detergent) in removing starch stains from fabrics with Ariel liquid detergent. In conclusion, amylase derived from the fungus Pleurotus pulmonarius CCB19 exhibited favorable properties that make it a suitable candidate for use as an additive in laundry detergent formulations.

The family Thermoactinomycetaceae: an emerging microbial resource with high application value

In recent years, interest has increased in the use of microorganisms to obtain additional valuable resources for green and sustainable development. Preliminary functional analyses have indicated that members of the family Thermoactinomycetaceae have good application potential for the production of novel specific enzymes, high-value bioactive compounds, novel secondary metabolites and the promotion of efficient biomass conversion. Therefore, they can be considered a new class of microbial resources with potentially high value. However, the lack of culture and culture-independent techniques coupled with the uncertain taxonomic status of the family Thermoactinomycetaceae, has made exploring these potential applications challenging. This paper reviews the distribution characteristics and functional properties of the family Thermoactinomycetaceae, providing a detailed interpretation of the potential application value of this group and proposing a set of systematic resource development strategies based on a combination of culture-dependent and culture-independent strategies to exploit its potential for resource applications.

Comparative study between the free and immobilized cells of Bacillus velezensis AMA2 P164707 and Bacillus atrophaeus AMA6 OP225343 for acidic β, α amylases production and applied experiment

Nowadays, acid-stable α-amylase demand is increasing in starch liquefaction processes. Four bacterial honey isolates, numbers 2 and 6 showed the highest amylase production on commercial starch as the sole medium component and were immobilized in alginate beads. The highest cell immobilization capacity was obtained by organisms' Bacillus velezensis AMA2 and Bacillus atrophaeus AMA6. Amylase production increases after the immobilization process from 78 to 232 U/mg and 71 to 216 U/mg for isolates numbers 2 and 6 respectively. The isolates were identified as Bacillus velezensis AMA2 and Bacillus atrophaeus AMA6, which produced β and α-amylases, respectively. They were able to retain 85 % and 53 % of their production after 7 cycles. The optimum temperature and pH for enzyme production shifted from 40 °C to 45 °C and the pHs 7 shifted to 6, after the immobilization. The immobilized cells for both isolates were more tolerant to the temperature elevation and the alkaline pHs than the free enzymes. Ca (NO3)2 stimulated the free and immobilized Bacillus velezensis AMA2 amylase production, and all other tested metals had adverse effects on both. The activation energy decreased after the immobilization process to 41.60 and 22.2-fold, respectively, and the t1/2 and D values increased. The enzymes showed high stability in the presence of different detergents.

Optimization and purification of a novel calcium-independent thermostable, α-amylase produced by Bacillus licheniformis UDS-5

Microbial amylases should essentially remain active at higher temperatures, and in the alkaline pH and a range of surfactants to be suitable as detergent additives. In the present study, a thermophilic amylase producing bacterium, Bacillus licheniformis UDS-5 was isolated from Unai hot water spring in Gujarat, India. It was identified as a potent amylase producer during starch plate-based screening process. Therefore, the physicochemical parameters influencing amylase production were optimized using Plackett-Burman design and Central Composite Design. The amylase was purified through ammonium sulfate precipitation, size exclusion and ion exchange chromatography, achieving the purification fold and yield to be 9.2 and 40.6%, respectively. The enzyme displayed robust stability and activity across a wide range of temperatures and pHs, with an increased half-life and reduced deactivation rate constant. The amylase exhibited optimal catalysis at 70 °C and pH 8. The kinetic studies revealed Km and Vmax values of 0.58 mg/mL and 2528 μmol/mL/min, respectively. Besides, the purified amylase displayed stability in the presence of various metal ions, surfactants, and chelators suggesting its potential for industrial applications, particularly in the detergent industry. Moreover, detergent application studies demonstrated its efficacy in enhancing washing performance. A comparative profile on washing efficiency of the studied amylase and the commercial amylase with various detergents pointed towards its possible future use as a detergent additive.

Expression optimization and characterization of a novel amylopullulanase from the thermophilic Cohnella sp. A01

Amylopullulanase (EC. 3.2.1.41/1) is an enzyme that hydrolyzes starch and pullulan, capable of breaking (4 → 1)-α and (6 → 1)-α bonds in starch. Here, the Amy1136 gene (2166 base pairs) from the thermophilic bacterium Cohnella sp. A01 was cloned into the expression vector pET-26b(+) and expressed in Escherichia coli BL21. The enzyme was purified using heat shock at 90 °C for 15 min. The expression optimization of Amy1136 was performed using Plackett-Burman and Box-Behnken design as follows: temperature of 26.7 °C, rotational speed of 180 rpm, and bacterial population of 1.25. The Amy1136 displayed the highest activity at a temperature of 50 °C (on pullulan) and a pH of 8.0 (on starch) and, also exhibited stability at high temperatures (90 °C) and over a range of pH values. Ag+ significantly increased enzyme activity, while Co2+ completely inhibited amylase activity. The enzyme was found to be calcium-independent. The kinetic parameters Km, Vmax, kcat, and kcat/Km for amylase activity were 2.4 mg/mL, 38.650 μmol min-1 mg-1, 38.1129 S-1, and 0.09269 S-1mg mL-1, respectively, and for pullulanase activity were 173.1 mg/mL, 59.337 μmol min-1 mg-1, 1.586 S-1, and 1.78338 S-1mg mL-1, respectively. The thermodynamic parameters Kin, t1/2, Ea#, ΔH#, ΔG# and ΔS# were calculated equal to 0.20 × 10-2 (m-1), 462.09 (min), 16.87 (kJ/mol), 14.18 (kJ/mol), 47.34 (kJ/mol) and 102.60 (Jmol K-1), respectively. The stability of Amy1136 under high temperature, acidic and alkaline pH, surfactants, organic solvents, and calcium independence, suggests its suitability for industrial applications.

Challenges and prospects of microbial α-amylases for industrial application: a review

α-Amylases are essential biocatalysts representing a billion-dollar market with significant long-term global demand. They have varied applications ranging from detergent, textile, and food sectors such as bakery to, more recently, biofuel industries. Microbial α-amylases have distinct advantages over their plant and animal counterparts owing to generally good activities and better stability at temperature and pH extremes. With the scope of applications expanding, the need for new and improved α-amylases is ever-growing. However, scaling up microbial α-amylase technology from the laboratory to industry for practical applications is impeded by several issues, ranging from mass transfer limitations, low enzyme yields, and energy-intensive product recovery that adds to high production costs. This review highlights the major challenges and prospects for the production of microbial α-amylases, considering the various avenues of industrial bioprocessing such as culture-independent approaches, nutrient optimization, bioreactor operations with design improvements, and product down-streaming approaches towards developing efficient α-amylases with high activity and recyclability. Since the sequence and structure of the enzyme play a crucial role in modulating its functional properties, we have also tried to analyze the structural composition of microbial α-amylase as a guide to its thermodynamic properties to identify the areas that can be targeted for enhancing the catalytic activity and thermostability of the enzyme through varied immobilization or selective enzyme engineering approaches. Also, the utilization of inexpensive and renewable substrates for enzyme production to isolate α-amylases with non-conventional applications has been briefly discussed.

Efficacy of the Fruit and Vegetable Peels as Substrates for the Growth and Production of α-Amylases in Marine Actinobacteria

Enzymes from haloalkaliphilic microorganisms have recently focused attention on their potential and suitability in various applications. In this study, the growth and production of extracellular amylases in the marine actinomycetes, using kitchen waste as the raw starch source, have been investigated. Actinobacteria were isolated from the seawater of the Kachhighadi Coast near Dwarika, Gujarat. Seven Actinobacterial isolates of pre-monsoon, monsoon, and post-monsoon seasons belonging to different strains of Nocardiopsis genera were screened and selected for amylase production. The amylase production was initially assessed on the solid media supplemented with the extracts of different fruits and vegetable peels as a substrate by agar plate assay. The strains Kh-2(13), Kh-2(1), and Kh-3(12) produced maximum amylase with potato peel as a substrate, while no significant differences were found with the media containing other peels. Nevertheless, all strains produced amylases at a significant level with other raw substrates as well. For the optimization of the growth and enzyme production, the selected two isolates Kh-2(13) and Kh-3(12) of the monsoon and winter seasons were cultivated in a liquid medium under the submerged fermentation conditions, with potato peel as a substrate. In both organisms, the optimum amylase production was observed in the stationary phase of growth. For amylase production, the effect of different physical and chemical parameters was evaluated. The optimum growth and amylase production was achieved in 2% inoculum size, at pH 8.0, 28℃, and 5% salt concentration. On the basis of the amylase production index (API) (a ratio of the amylase units and cell growth), both isolates produced significant amylase with the only extract of potato peels, without any other supplements. The trends further indicated that while additional complex sources, such as yeast extract and peptone can enhance the cell growth of the actinobacteria, the amylase production remained unaltered. The study projects the significance of waste raw materials for the production of enzymes in extremophilic microorganisms.

Solvent tolerant enzymes in extremophiles: Adaptations and applications

Non-aqueous enzymology has always drawn attention due to the wide range of unique possibilities in biocatalysis. In general, the enzymes do not or insignificantly catalyze substrate in the presence of solvents. This is due to the interfering interactions of the solvents between enzyme and water molecules at the interface. Therefore, information about solvent-stable enzymes is scarce. Yet, solvent-stable enzymes prove quite valuable in the present day biotechnology. The enzymatic hydrolysis of the substrates in solvents synthesizes commercially valuable products, such as peptides, esters, and other transesterification products. Extremophiles, the most valuable yet not extensively explored candidates, can be an excellent source to investigate this avenue. Due to inherent structural attributes, many extremozymes can catalyze and maintain stability in organic solvents. In the present review, we aim to consolidate information about the solvent-stable enzymes from various extremophilic microorganisms. Further, it would be interesting to learn about the mechanism adapted by these microorganisms to sustain solvent stress. Various approaches to protein engineering are used to enhance catalytic flexibility and stability and broaden biocatalysis's prospects under non-aqueous conditions. It also describes strategies to achieve optimal immobilization with minimum inhibition of the catalysis. The proposed review would significantly aid our understanding of non-aqueous enzymology.

Discovery of a New Microbial Origin Cold-Active Neopullulanase Capable for Effective Conversion of Pullulan to Panose

Panose is a type of functional sugar with diverse bioactivities. The enzymatic conversion bioprocess to produce high purity panose with high efficiency has become increasingly important. Here, a new neopullulanase (NPase), Amy117 from B. pseudofirmus 703, was identified and characterized. Amy117 presented the optimal activity at pH 7.0 and 30 °C, its activity is over 40% at 10 °C and over 80% at 20 °C, which is cold-active. The enzyme cleaved α-1, 4-glycosidic linkages of pullulan to generate panose as the only hydrolysis product, and degraded cyclodextrins (CDs) and starch to glucose and maltose, with an apparent preference for CDs. Furthermore, Amy117 can produce 72.7 mg/mL panose with a conversion yield of 91% (w/w) based on 80 mg/mL pullulan. The sequence and structure analysis showed that the low proportion of Arg, high proportion of Asn and Gln, and high α-helix levels in Amy117 may contribute to its cold-active properties. Root mean square deviation (RMSD) analysis also showed that Amy117 is more flexible than two mesophilic homologues. Hence, we discovered a new high-efficiency panose-producing NPase, which so far achieves the highest panose production and would be an ideal candidate in the food industry.

Utilization of starch effluent from a textile industry as a fungal growth supplement for enhanced α-amylase production for industrial application

Desizing process in textile industry produces large volume of starch effluent. This carbon-rich waste can be used for resource recovery, such as the production of industrially useful enzymes. The present work assesses the usability of starch effluent from textile industry as an additional carbon source for enhanced production of α-amylase during solid-state fermentation (SSF) of agro-wastes by Trichoderma reesei. A significant increase (p ≤ 0.05) in α-amylase activity (25.48 ± 1.12 U mL^-1) was observed with supplementation of starch effluent in SSF. Partial purification of α-amylase by 80% ammonium sulphate precipitation produced a yield of 58.39% enzyme with purification fold of 1.89. The enzyme was thermally stable at 40 °C with 90% residual activity after 5 h and 70% residual activity at 50 °C after 3 h. Using Michaelis-Menten kinetics analysis, the estimated K_m and V_max values for the partially purified α-amylase were found to be 2.55 mg mL^-1 and 53.47 U mg^-1, respectively. For the rapid assessment of the industrial application, desizing of the fabric was attempted. The cotton fabric was efficiently desized using α-amylase (at a concentration of 1% on the weight of fabric basis) at 80 °C. The present work demonstrates starch effluent from desizing process as a resource for the production of amylase. The amylase can further be used in the desizing process. With in-depth research, the work may lead to the development of a closed-loop, waste-recycling process for the textile industry.

Amylases from thermophilic bacteria: structure and function relationship

Amylases hydrolyze starch to diverse products including dextrins and progressively smaller polymers of glucose units. Thermally stable amylases account for nearly 25% of the enzyme market. This review highlights the structural attributes of the α-amylases from thermophilic bacteria. Heterologous expression of amylases in suitable hosts is discussed in detail. Further, specific value maximization approaches, such as protein engineering and immobilization of the amylases are discussed in order to improve its suitability for varied applications on a commercial scale. The review also takes into account of the immobilization of the amylases on nanomaterials to increase the stability and reusability of the enzymes. The function-based metagenomics would provide opportunities for searching amylases with novel characteristics. The review is expected to explore novel amylases for future potential applications.

Synergetic modification of waxy maize starch by dual-enzyme to lower the in vitro digestibility through modulating molecular structure and malto-oligosaccharide content

Cyclodextrinase (CDase) and cyclodextrin glucosyltransferase (CGTase) were synergistically used to provide a novel enzymatic method in lowing in vitro digestibility of waxy maize starch. The molecular structure, malto-oligosaccharide composition, and digestibility properties of the generated products were investigated. The molecular weight was reduced to 0.3 × 10⁵ g/mol and 0.2 × 10⁵ g/mol by simultaneous and sequential treatment with CDase and CGTase, while the highest proportion of chains with degree of polymerization (DP) < 13 was obtained by simultaneous treatment. The resistant starch contents were increased to 27.5% and 36.9% by simultaneous and sequential treatments respectively. Dual-enzyme treatment significantly promoted the content of malto-oligosaccharides (MOSs) by hydrolyzing cyclodextrins from CGTase with CDase. However, the replacement of cyclodextrins by MOSs did not obviously influence the digestibility of the products. The starch digestion kinetics further revealed the hydrolysis pattern of these two enzymes on the starch hydrolysate. It was proved that the starch digestibility could be lowered by modulating the molecular structure and beneficial MOSs content by this dual-enzyme treatment.

Comparative growth potential of thermophilic amylolytic Bacillus sp. on unconventional media food wastes and its industrial application

Amylases take part with vital role in industries such as food, fermentation; starch processing, textile and paper etc. Increasing amylases demand, high nutrient expenditure and environmental pollution have forced to utilize agro-industrial residues as a low-cost feedstock for enzyme production. In present study, three soil samples were collected from agro-industrial waste dumping areas in District Faisalabad. Ten thermophilic bacterial isolates were separated at 55 °C on the basis of colonial morphology, three isolates (F6, F11, F17) showed prominent zone of clearance applying iodine test on starch agar plates. Bacterial isolate F-11 showed highest amylase activity with DNS method and molecularly identified through 16S RNA sequencing as Bacillus sp. with Accession number MH917294. Four unconventional food wastes (banana, lemon, mango and potato) pretreated with 0.8% sulphuric acid concentrations taking 1000 g/L weight released the highest sugars contents and phenolic components. Maximum amylase activity i.e. 29.23 mg/ml was achieved in mango waste at, 40 °C, with pH 6.0 and 0.17% nitrogenous source adding 8% inoculum size (2 days old) using Response Surface Methodology (RSM) for optimization. Crude amylase confirmed its efficiency in starch hydrolysis that suggested it as potential candidate for application in starch industries.

Identification and characterization of novel thermostable α-amylase from Geobacillus sp. GS33

In this study, the heterologous expression and biochemical characterization of a thermostable α-amylase from Geobacillus sp. GS33 was investigated. The recombinant α-amylase was overexpressed in Escherichia coli BL21 (λDE) and purified via anion exchange and size-exclusion chromatography. The purified α-amylase had a molecular weight of about 60 kDa, and was active in a broad range of pH 3-10 and temperature (40-90 °C) with maximum activity at pH 7-8 and 60 °C. The enzyme retained 50% residual activity at 65 °C, but only 20% at 85 °C after 16 h. At pH 9 and pH 7, the residual activity at 65 °C was 50% and 30%, respectively. The enzyme was remarkably activated by Co²⁺, Ca²⁺, Mg²⁺, PMSF, DTT, and Triton X-100, but partially inhibited by Cu²⁺, methanol, hexane, ethanol, acetone, SDS, and Tween 20. A molecular phylogeny analysis showed that the enzyme's amino acid sequence had the closest connection with an α-amylase from Geobacillus thermoleovorans subsp. stromboliensis nov. 3D-structure-based amino acid sequence alignments revealed that the three catalytic residues (D217, E246, D314) and the four Ca²⁺ ion coordination residues (N143, E177, D186, H221) were conserved in α-amylase from Geobacillus sp. GS33. The temperature stability and neutral pH optimum suggest that the enzyme may be useful for industrial applications.

Catalytic and thermodynamic properties of an acidic α-amylase produced by the fungus Paecilomyces variotii ATHUM 8891

An extracellular acid stable α-amylase from Paecilomyces variotii ATHUM 8891 (PV8891 α-amylase) was purified to homogeneity applying ammonium sulfate fractionation, ion exchange and gel filtration chromatography and exhibited a reduced molecular weight of 75 kDa. The purified enzyme was optimally active at pH 5.0 and 60 °C and stable in acidic pH (3.0-6.0). K _m, v _max and k _cat for starch hydrolysis were found 1.1 g L^-1, 58.5 μmole min^-1 (mg protein)^-1, and 73.1 s^-1, respectively. Amylase activity was marginally enhanced by Ca²⁺ and Fe²⁺ ions while Cu²⁺ ions strongly inhibited it. Thermodynamic parameters determined for starch hydrolysis (Ε _α, ΔH*, ΔG*, ΔS*, Δ G E - S ∗ and Δ G E - T ∗ ) suggests an effective capacity of PV8891 α-amylase towards starch hydrolysis. Thermal stability of PV8891 α-amylase was assessed at different temperatures (30-80 ^οC). Thermodynamic parameters ( E a d , ΔH*, ΔG*, ΔS*) as well as the integral activity of a continuous system for starch hydrolysis by the PV8891 α-amylase revealed satisfactory thermostability up to 60 °C. The acidic nature and its satisfactory performance at temperatures lower than the industrially used amylases may represent potential applications of PV8891 α-amylase in starch processing industry.

Biochemical, thermodynamic and structural characteristics of a biotechnologically compatible alkaline protease from a haloalkaliphilic, Nocardiopsis dassonvillei OK-18

This report describes purification strategies, biochemical properties and thermodynamic analysis of an alkaline serine protease from a marine actinomycete, Nocardiopsis dassonvillei strain OK-18. The solvent tolerance, broad thermal-pH stability, favourable kinetics and thermodynamics suggest stability of the enzymatic reaction. The enzyme was active in the range of pH 7-12 and 37-90 °C, optimally at pH 9 and 70 °C. The deactivation rate constant (Kd), half-life (t½), enthalpy (ΔH*), entropy (ΔS*), activation energy (E) and change in free energy (ΔG*) suggested stability and spontaneity of the reaction. β-Sheets as revealed by the Circular dichroism (CD) spectroscopy, were the major elements in the secondary structure of the enzyme, while Fourier-transform infrared spectroscopy (FTIR) indicated the presence of amide I and amide II. Based on the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis, the amino acid sequence had only 38% similarity with other proteases of Nocardiopsis strains, suggesting its novelty. The Ramachandran Plot revealed the location of the amino acid residues in the most favored region. The blood de-staining, gelatin hydrolysis, silver recovery and deproteinization of crab shells established the biotechnological potential of the enzyme.

The complete genome sequence of the thermophilic bacterium Laceyella sacchari FBKL4.010 reveals the basis for tetramethylpyrazine biosynthesis in Moutai-flavor Daqu

The genus Laceyella consists of a thermophilic filamentous bacteria. The pure isolate of Laceyella sacchari FBKL4.010 was isolated from Moutai‐flavor Daqu, Guizhou Province, China. In this study, the whole genome was sequenced and analyzed. The complete genome consists of one 3,374,379‐bp circular chromosome with 3,145 coding sequences (CDSs), seven clustered regularly interspaced short palindromic repeat (CRISPR) regions of 12 CRISPRs. Moreover, we identified that the genome contains genes encoding key enzymes such as proteases, peptidases, and acetolactate synthase (ALS) of the tetramethylpyrazine metabolic pathway. Metabolic pathways relevant to tetramethylpyrazine synthesis were also reconstructed based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) PATHWAY database. Annotation and syntenic analyses using antiSMASH 4.0 also revealed the presence of two gene clusters in this strain that differ from known tetramethylpyrazine synthesis clusters, with one encoding amino acid dehydrogenase (ADH) and the other encoding transaminase in tetramethylpyrazine metabolism. The results of this study provide flavor and genomic references for further research on the flavor‐producing functions of strain FBKL4.010 in the Moutai liquor‐making process.

Optimization of aqueous two-phase partitioning of Aureobasidium pullulans α-amylase via response surface methodology and investigation of its thermodynamic and kinetic properties

Industrial enzymes such as α-amylase must be thermostable and also easily purified/concentrated. Hence, aqueous two-phase partitioning systems (ATPS) was exploited for the partitioning of α-amylase from Aureobasidium pullulans due to its numerous advantages over conventional purification strategy. A. pullulans α-amylase was partially purified using ATPS via response surface methodology (RSM). The potentials of the ATPS-purified enzyme for possible industrial application such as resistance to thermal inactivation was investigated in comparison with the crude enzyme. PEG-6000 was the polymer of choice for ATPS as it resulted in higher purification factor (PF), %yield (Y), and partition coefficient (PC). At optimum levels (% w/v) of 20, 12 and 7.5 for PEG-6000, sodium citrate and sodium chloride respectively, maximum PF, Y and PC of 4.2, 88%, and 9.9 respectively were obtained. The response model validation and reliability were established based on the closeness between the experimented and predicted values. The kinetic and thermodynamic parameters such as Q₁₀, t_1/2, k_d, D - value, E_d, [Formula: see text] [Formula: see text] of the ATPS-purified α-amylase indicated that it was thermostable at 50 to 60 °C compared to the crude α-amylase. A thermodynamically stable and ATPS-purified α-amylase from A. pullulans has properties easily applicable for most industrial processes.

Optimization and partial characterization of ca-independent α-amylase from Bacillus amyloliquefaciens BH1

Strain Bacillus amyloliquefaciens BH1 was evaluated for the generation of α-amylase. Culture conditions and medium components were optimized by a statistical approach for the optimal generation of α-amylase with response surface methodology (RSM) method. The Plackett-Burman (PB) design was executed to select the fermentation variables and Central composite design (CCD) for optimizing significant factors influencing production. The optimum levels for highest generation of α-amylase activity (198.26 ± 3.54 U/mL) were measured. A 1.69-fold improve generation was acquired in comparison with the non-optimized. Partial characterization of the α-amylase indicated optimal pH and temperature at 7.0 and 40 °C, respectively. Crude α-amylase maintained a constant pH range 5.0-8.0 and 30-70 °C. The α-amylase was independent of Ca²⁺, and the activity was inhibited by Fe³⁺, Co²⁺, Cu²⁺, and Hg²⁺. The thermo and pH stability of the α-amylase indicate its extensive application in the food and pharmaceutical industries.

Optimization, Purification, and Starch Stain Wash Application of Two New α-Amylases Extracted from Leaves and Stems of Pergularia tomentosa

A continuous research is attempted to fulfil the highest industrial demands of natural amylases presenting special properties. New α-amylases extracted from stems and leaves of Pergularia tomentosa, which is widespread and growing spontaneously in Tunisia, were studied by the means of their activities optimization and purification. Some similarities were recorded for the two identified enzymes: (i) the highest amylase activity showed a promoted thermal stability at 50°C; (ii) the starch substrate at 1% enhanced the enzyme activity; (iii) the two α-amylases seem to be calcium-independent; (iv) Zn2+, Cu2+, and Ag2+ were considered as important inhibitors of the enzyme activity. Following the increased gradient of elution on Mono Q-Sepharose column, an increase in the specific activity of 11.82-fold and 10.92-fold was recorded, respectively, for leaves and stems with the presence of different peaks on the purification profiles. Pergularia amylases activities were stable and compatible with the tested commercial detergents. The combination of plant amylase and detergent allowed us to enhance the wash performance with an increase of 35.24 and 42.56%, respectively, for stems and leaves amylases. Characterized amylases were reported to have a promoted potential for their implication notably in detergent industry as well as biotechnological sector.

Production and Partial Characterization of α-Amylase Enzyme from Bacillus sp. BCC 01-50 and Potential Applications

Amylase is an industrially important enzyme and applied in many industrial processes such as saccharification of starchy materials, food, pharmaceutical, detergent, and textile industries. This research work deals with the optimization of fermentation conditions for α-amylase production from thermophilic bacterial strain Bacillus sp. BCC 01-50 and characterization of crude amylase. The time profile of bacterial growth and amylase production was investigated in synthetic medium and maximum enzyme titer was observed after 60 h. In addition, effects of different carbon sources were tested as a substrate for amylase production and molasses was found to be the best. Various organic and inorganic compounds, potassium nitrate, ammonium chloride, sodium nitrate, urea, yeast extract, tryptone, beef extract, and peptone, were used and beef extract was found to be the best among the nitrogen sources used. Temperature, pH, agitation speed, and size of inoculum were also optimized. Highest enzyme activity was obtained when the strain was cultured in molasses medium for 60 h in shaking incubator (150 rpm) at 50°C and pH 8. Crude amylase showed maximal activity at pH 9 and 65°C. Enzyme remained stable in alkaline pH range 9-10 and 60-70°C. Crude amylase showed great potential for its application in detergent industry and saccharification of starchy materials.