Isolation and characterization of a novel thermostable α-amylase from Korean pine seeds

Antimicrobial therapeutic protein extraction from fruit waste and recent trends in their utilization against infections

Fruits are a very good source of various nutrients that can boost overall human health. In these days, the recovery of therapeutic compounds from different fruit wastes is trending in research, which might not only minimize the waste problem but also encounter a higher demand for various enzymes that could have antimicrobial properties against infectious diseases. The goal of this review is to focus on the recovery of therapeutic enzymes from fruit wastes and its present-day tendency for utilization. Here we discussed different parts of fruit waste, such as pulp, pomace, seed, kernel, peel, etc., that produce therapeutic enzymes like amylase, cellulose, lipase, laccase, pectinase, etc. These bioactive enzymes are present in different parts of fruit and could be used as therapeutics against various infectious diseases. This article provides a thorough knowledge compilation of therapeutic enzyme isolation from fruit waste on a single platform, distinctly informative, and significant review work on the topic that is envisioned to encourage further research ideas in these areas that are still under-explored. This paper explains the various aspects of enzyme isolation from fruit and vegetable waste and their biotherapeutic potential that could provide new insights into the development of biotherapeutics and attract the attention of researchers to enhance translational research magnitude further.

Metagenomic views on taxonomic and functional profiles of the Himalayan Tsomgo cold lake and unveiling its deterzome potential

Cold habitat is considered a potential source for detergent industry enzymes. This study aims at the metagenomic investigation of Tsomgo lake for taxonomic and functional annotation, unveiling the deterzome potential of the residing microbiota at this site. The present investigation revealed molecular profiling of microbial community structure and functional potential of the high-altitude Tsomgo lake samples of two different temperatures, harvested during March and August. Bacteria were found to be the most dominant phyla, with traces of genomic pieces of evidence belonging to archaea, viruses, and eukaryotes. Proteobacteria and Actinobacteria were noted to be the most abundant bacterial phyla in the cold lake. In-depth metagenomic investigation of the cold aquatic habitat revealed novel genes encoding detergent enzymes, amylase, protease, and lipase. Further, metagenome-assembled genomes (MAGs) belonging to the psychrophilic bacterium, Arthrobacter alpinus, were constructed from the metagenomic data. The annotation depicted the presence of detergent enzymes and genes for low-temperature adaptation in Arthrobacter alpinus. Psychrophilic microbial isolates were screened for lipase, protease, and amylase activities to further strengthen the metagenomic findings. A novel strain of Acinetobacter sp. was identified with the dual enzymatic activity of protease and amylase. The bacterial isolates exhibited hydrolyzing activity at low temperatures. This metagenomic study divulged novel genomic resources for detergent industry enzymes, and the bacterial isolates secreting cold-active amylase, lipase, and protease enzymes. The findings manifest that Tsomgo lake is a potential bioresource of cold-active enzymes, vital for various industrial applications.

Plant growth-promoting properties of bacterial endophytes isolated from roots of Thymus vulgaris L. and investigate their role as biofertilizers to enhance the essential oil contents

The main objective of the current study was to improve the essential oil contents of Thymus vulgaris L. using bio-inoculation with bacterial endophytes. Therefore, out of fourteen endophytic bacterial isolates obtained from roots of T. vulgaris, five isolates were selected based on the highest nitrogen-fixation and phosphate solubilization activity and identified as: Bacillus haynesii T9r, Citrobacter farmeri T10r, Bacillus licheniformis T11r, Bacillus velezensis T12r, and Bacillus velezensis T13r. These five strains have been recorded as ammonia, hydrogen cyanide (HCN), siderophores, and indole-3-acetic acid (IAA) producers. These strains have the efficacy to fix-nitrogen by reduction of acetylene with values of 82.133±1.4-346.6±1.4 n-mole-C₂H₄/ml/24 h. The IAA, gibberellic acid, abscisic acid, benzyl, kinten, and ziaten production were confirmed using HPLC. Two strains of T11r and T13r showed the highest plant growth-promoting properties and were selected for bio-inoculation of T. vulgaris individually or in a consortium with different mineral fertilization doses (0, 50, 75, and 100%) under field conditions. The highest growth performance was attained with the endophytic consortium (T11r+T13r) in the presence of 100% mineral fertilization. The GC-MS analysis of thyme oil contents showed the presence of 23 various compounds with varying percentages and the thymol fraction represented the highest percentages (39.1%) in the presence of the bacterial consortium.

Artificial AmyR::XlnR transcription factor induces α-amylase production in response to non-edible xylan-containing hemicellulosic biomass

Filamentous fungi belonging to the Aspergillus genus are one of the most favored microorganisms for industrial enzyme production because they can secrete large amounts of proteins into the culture medium. α-Amylase, an enzyme produced by Aspergillus species, is important for food and industrial applications. The production of α-amylase is induced by starch, mainly obtained from the edible biomass; however, the increasing demand for foods is limiting the application of the latter. Therefore, it is expected that using the non-edible biomass, such as rice straw, could improve the competition for industrial application starch containing resources. The transcription factor AmyR activates the transcription of amylolytic enzyme genes, while the transcription factor XlnR activates the transcription of xylanolytic enzyme genes in response to xylose. In this study, we aimed to construct an artificial AmyR::XlnR transcription factor (AXTF) by replacing the DNA-binding domain (1-159 amino acids) of XlnR with that (1-68 aa) of AmyR, which is capable of inducing amylolytic enzyme production in response to xylan-containing hemicellulosic biomass. The chimeric transcription factor AXTF was constructed and expressed using the gapA promoter in the amyR-deficient mutant strain SA1. When the AXTF strain was cultured in the minimal medium containing xylose as the carbon source, the amyB, amyF, agdB, and agdE transcription levels were 41.1-, 11.3-, 37.9-, and 23.7-fold higher, respectively, than those of the wild-type strain. The α-amylase and α-glucosidase activities in the culture supernatant of the AXTF strain grown with xylose for 48 h were 696.6 and 536.1 U/mL, respectively, while these activities were not detected in the culture supernatant of the wild-type and SA1 strains. When rice straw hydrolysate was used as a carbon source, the α-amylase and α-glucosidase activities were 590.2 and 362.7 U/mL, respectively. Thus, we successfully generated an Aspergillus nidulans strain showing amylolytic enzyme production in response to non-edible xylan-containing hemicellulosic biomass by transforming it with the chimeric transcription factor AXTF. Furthermore, the use of genes encoding engineered transcription factors is advantageous because introducing such genes into an industrial Aspergillus strain has similar simultaneous effects on multiple amylase genes controlled by AmyR.

Production, characterization and application of thermostable, alkaline α-amylase (AA11) from Bacillus cereus strain SP-CH11 isolated from Chilika Lake

An alkaliphile bacterial strain designated as CH11 was isolated from the sediments of Chilika Lake, Odisha. The isolate showed stupendous growth and production of α-amylase at pH 10.0. Through 16S rRNA gene based molecular technique this isolate was identified as Bacillus cereus strain SP-CH11 having GenBank Accession No. KT992791. Homogenous ~55 kDa extracellular α-amylase was extracted with 241.304, 26.26 and 3.2-fold acceleration in specific activity, purification fold and yield respectively. The alkaline α-amylase AA11 was further characterized. At pH 9.0 the purified enzyme AA11 was highly stable while retaining 88-100% functional viability at temperature range from 35 to 65 °C, confirming its thermostability nature. It showed stability with powdered and liquid detergents at 7 mg/mL and 100-fold dilutions respectively. AA11 efficiently removed the starch stain from cotton fabrics. The findings of this study indicate that the isolate CH11 is a source of novel alkaline α-amylase that has promising application in food and detergent 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.

Insights into the functionality of endophytic actinobacteria with a focus on their biosynthetic potential and secondary metabolites production

Endophytic actinobacteria play an important role in growth promotion and development of host plant by producing enormous quantities of novel bioactive natural products. In the present investigation, 169 endophytic actinobacteria were isolated from endospheric tissues of Rhynchotoechum ellipticum. Based on their antimicrobial potential, 81 strains were identified by 16rRNA gene analysis, which were taxonomically grouped into 15 genera. All identified strains were screened for their plant growth promoting attributes and, for the presence of modular polyketide synthases (PKSI, PKSII and nonribosomal peptide synthetase (NRPS) gene clusters to correlate the biosynthetic genes with their functional properties. Expression studies and antioxidant potential for four representative strains were evaluated using qRT-PCR and DPPH assay respectively. Additionally, six antibiotics (erythromycin, ketoconazole, fluconazole, chloramphenicol, rifampicin and miconazole) and nine phenolic compounds (catechin, kaempferol, chebulagic acid, chlorogenic acid, Asiatic acid, ferulic acid, arjunic acid, gallic acid and boswellic acid) were detected and quantified using UHPLC-QqQ_LIT-MS/MS. Furthermore, three strains (BPSAC77, 121 and 101) showed the presence of the anticancerous compound paclitaxel which was reported for the first time from endophytic actinobacteria. This study provides a holistic picture, that endophytic actinobacteria are rich bacterial resource for bioactive natural products, which has a great prospective in agriculture and pharmaceutical industries.

Extraction, partial purification and characterization of amylase from parthenocarpic date (Phoenix dactylifera): effect on cake quality

BACKGROUND

Phoenix dactylifera L. plays an important role in social, economic and ecological Tunisian sectors. Some date palms produce parthenocarpic fruit named Sish. The objective of the present study was to extract biomolecules from parthenocarpic fruit by producing value-added products from the fruits.

RESULTS

The extraction of amylolytic activity from parthenocarpic fruit (AmyPF) was optimized using Box-Behnken design (BBD). Partial purification of about 250-fold with an activity yield of 47% was achieved. The amylase exhibited a specific activity of 80 U mg^-1 protein. The optimum pH and temperature for enzyme activity were 5 and 55 °C respectively. The enzyme was highly active over a wide range of pH (5-10), and significant stabilization was observed at 60 °C. The purified enzyme belongs to the exo type of amylases. Given the economic and industrial relevance of amylases used in the food industry, three different concentrations of AmyPF (0.007, 0.014 and 0.018 U g^-1 ) were incorporated into a cake formulation, resulting in a decrease in density, moisture retention and water activity and an increase in hardness.

CONCLUSION

The beneficial effect of AmyPF on the technological characteristics of cakes was confirmed by sensory evaluation. © 2017 Society of Chemical Industry.

Phytohormone production endowed with antagonistic potential and plant growth promoting abilities of culturable endophytic bacteria isolated from Clerodendrum colebrookianum Walp

In this study, culturable endophytic bacterial isolates obtained from an ethnomedicinal plant Clerodendrum colebrookianum Walp., were assessed for their diversity, in vitro screening for their plant growth promoting (PGP) activities and to use them as inoculant for in vivo PGP activities with biocontrol potential. Totally, 73 isolates were recovered from different tissues of C. colebrookianum were identified by 16S rRNA gene sequencing and phylogenetically analyzed by using BOX-PCR fingerprinting. Out of 73 isolates, 52 exhibited varying extents of antagonistic potential were selected for screening for various PGP traits. Concerning the PGP activities, the percentage of isolates positive for P-solubilisation, indolic compounds production, siderophore and ammonia production were 84.6, 92.3, 78.8 and 98.0 respectively. All isolates were positive for the production of hydrocyanic acid (HCN) and 86.5%, 84.6% and 90.3% of isolates showed significant cellulase, amylase and protease production respectively. Further, the top 10 bacterial isolates based on a bonitur scale with multiple PGP activities were screened for root surface colonization and biofilm formation ability. Out of selected 10 isolates, 9 showed significant potential for root surface colonization on tomato roots. Isolate BPSAC6 identified as Bacillus sp. was most efficient in biofilm formation as assessed with respect to the intensity of crystal violet, which further showed their potential to withstand various biotic and abiotic stresses. Furthermore, Bacillus sp. strain BPSAC6 showed a significant increase in shoot and root height as well as fresh weight after 45 and 60 d of inoculation with tomato seedlings. Additionally, biosynthetic potential of antagonistic isolate was detection by using PKSI, PKSII and NRPS biosynthetic genes. Two isolates Pseudomonas psychrotolerans and Labrys wisconsinensis were reported first time as an endophyte. At last, first time an endophytic bacterial strain Bacillus sp. BPSAC6 was reported to produce altogether three phytohormones (IAA, Kinetin and 6-Benzyladenine). This study is the first report that bacteria isolated from C. colebrookianum has biocontrol as well as PGP abilities endowed with phytohormones production and can be used for the preparation of bioinoculant for plant growth promotion.

Isolation and characterisation of a novel alpha-amylase from the extreme haloarchaeon Haloterrigena turkmenica

An extracellular halophilic alpha-amylase (AmyA) was produced by the haloarchaeon Haloterrigena turkmenica grown in medium enriched with 0.2% (w/v) starch. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) analyses showed a major band at 66.0kDa and a peak of 54.0kDa, respectively. Analysis of tryptic fragments of the protein present in the major SDS-PAGE band by nano-LC-ESI-MS/MS led to identification of the alpha-amylase catalytic region, encoded by the htur2110 gene, as the protein possessing the described activity. Optimal values for activity were 55°C, pH 8.5 and 2M NaCl, and high thermostability was showed at 55°C and 3M NaCl. AmyA activity was enhanced by Triton X-100 and was not influenced by n-hexane and chloroform. Starch hydrolysis produced different oligomers with maltose as the smallest end-product. The efficiency of AmyA in degrading starch contained in agronomic residues was tested in grape cane chosen as model substrate. Preliminary results showed that starch was degraded making the enzyme a potential candidate for utilization of agro-industrial waste in fuel and chemicals production. AmyA is one of the few investigated amylases produced by haloarchaea, and the first alpha-amylase described among microorganisms belonging to the genus Haloterrigena.

Cow dung is an ideal fermentation medium for amylase production in solid-state fermentation by Bacillus cereus

Amylase production by Bacillus cereus IND4 was investigated by solid state fermentation (SSF) using cow dung substrate. The SSF conditions were optimized by using one-variable-at-a-time approach and two level full factorial design. Two level full factorial design demonstrated that moisture, pH, fructose, yeast extract and ammonium sulphate have significantly influenced enzyme production (p < 0.05). A central composite design was employed to investigate the optimum concentration of these variables affecting amylase production. Maximal amylase production of 464 units/ml of enzyme was observed in the presence of 100% moisture, 0.1% fructose and 0.01% ammonium sulphate. The enzyme production increased three fold compared to the original medium. The optimum pH and temperature for the activity of amylase were found to be 8.0 and 50 °C, respectively. This enzyme was highly stable at wide pH range (7.0-9.0) and showed 32% enzyme activity after initial denaturation at 50 °C for 1 h. This is the first detailed report on the production of amylase by microorganisms using cow dung as the low cost medium.

Molecular Identification of a Newly Isolated Bacillus subtilis BI19 and Optimization of Production Conditions for Enhanced Production of Extracellular Amylase

A study was carried out with a newly isolated bacterial strain yielding extracellular amylase. The phylogenetic tree constructed on the basis of 16S rDNA gene sequences revealed this strain as clustered with the closest members of Bacillus sp. and identified as Bacillus subtilis BI19. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Rice flour (1.25%) as a cheap natural carbon source was found to induce amylase production mostly. A combination of peptone and tryptone as organic and ammonium sulfate as inorganic nitrogen sources gave highest yield. Maximum production was obtained after 24 h of incubation at 37 °C with an initial medium pH 8.0. Addition of surfactants like Tween 80 (0.25 g/L) and sodium lauryl sulfate (0.2 g/L) resulted in 28% and 15% increase in enzyme production, respectively. Amylase production was 3.06 times higher when optimized production conditions were used. Optimum reaction temperature and pH for crude amylase activity were 50 °C and 6.0, respectively. The crude enzyme showed activity and stability over a fair range of temperature and pH. These results suggest that B. subtilis BI19 could be exploited for production of amylase at relatively low cost and time.

Optimization of processing parameters for extraction of amylase enzyme from dragon (Hylocereus polyrhizus) peel using response surface methodology

The main goal of this study was to investigate the effect of extraction conditions on the enzymatic properties of thermoacidic amylase enzyme derived from dragon peel. The studied extraction variables were the buffer-to-sample (B/S) ratio (1:2 to 1:6, w/w), temperature (-18°C to 25°), mixing time (60 to 180 seconds), and the pH of the buffer (2.0 to 8.0). The results indicate that the enzyme extraction conditions exhibited the least significant (P < 0.05) effect on temperature stability. Conversely, the extraction conditions had the most significant (P < 0.05) effect on the specific activity and pH stability. The results also reveal that the main effect of the B/S ratio, followed by its interaction with the pH of the buffer, was significant (P < 0.05) among most of the response variables studied. The optimum extraction condition caused the amylase to achieve high enzyme activity (648.4 U), specific activity (14.2 U/mg), temperature stability (88.4%), pH stability (85.2%), surfactant agent stability (87.2%), and storage stability (90.3%).

Purification and characterization of thermostable α-amylase from thermophilic Anoxybacillus flavithermus

This study reports on the purification and characterization of thermostable α-amylase (α-1-4 D-glucan glucanohydrolase EC 3.2.1.1) from a newly isolated Anoxybacillus flavithermus. A. flavithermus was used, which was isolated from hot water springs of Ömer, Afyonkarahisar, Turkey. The gram-positive, spore-forming, motile, moderately thermophilic bacteria were found to be a strain of A. flavithermus analysed by 16S rRNA comparison. The optimal conditions for bacterial growth were determined to be at 20 thh, 55 °C and pH 6.0. Maximum α-amylase activity was obtained at 55 °C at pH 7.0 after 24h of incubation. Thermostable α-amylase from A. flavithermus was purified by 70% (NH4)2SO4 and ion-exchange chromatography (5.2-fold; 65.8% yield). The molecular weight of α-amylase was 60 kDa, as estimated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The α-amylase hydrolyzed soluble starch at 55 °C with Km: 0.005 mM and Vmax: 3.5 μmol min(-1).

Production and partial characterization of extracellular amylase enzyme from Bacillus amyloliquefaciens P-001

Amylases are one of the most important enzymes in present-day biotechnology. The present study was concerned with the production and partial characterization of extracellular amylase from Bacillus amyloliquefaciens P-001. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Enzyme production was induced by a variety of starchy substrate but corn flour was found to be a suitable natural source for maximum production. Tryptone and ammonium nitrate (0.2%) as nitrogen sources gave higher yield compared to other nitrogen sources. Maximum enzyme production was obtained after 48 hrs of incubation in a fermentation medium with initial pH 9.0 at 42°C under continuous agitation at 150 rpm. The size of inoculum was also optimized which was found to be 1% (v/v). Enzyme production was 2.43 times higher after optimizing the production conditions as compared to the basal media. Studies on crude amylase revealed that optimum pH, temperature and reaction time of enzyme activity was 6.5, 60°C and 40 minutes respectively. About 73% of the activity retained after heating the crude enzyme solution at 50°C for 30 min. The enzyme was activated by Ca²⁺ (relative activity 146.25%). It was strongly inhibited by Mn²⁺, Zn²⁺ and Cu²⁺, but less affected by Mg²⁺ and Fe²⁺.

Purification and characterization of an amylase from Opuntiaficus-indica seeds

BACKGROUND

In Tunisia, prickly pear fruit grow spontaneously; it is consumed as fresh fruit, juice or jam. When the fruit is used for juice production, the seeds are discarded and go to waste. Our study aimed to extract biomolecules from seeds by producing value-added products from the fruits.

RESULTS

An amylase from Opuntia ficus-indica seeds was extracted and purified to homogeneity. An increase in specific activity of 113-fold was observed. The apparent molecular mass of the enzyme is 64 kDa. The optimum pH and temperature for enzyme activity were pH 5 and 60 °C, respectively. Under these conditions, the specific activity is 245.5 U mg(-1) . The enzyme was activated by Co(2+) and Mg(2+) (relative activity 117% and 113% respectively) at lower ion concentrations. It was strongly inhibited by Mn(2+) and Fe(2+) . Cu(2+) inhibited totally the activity of this enzyme, but Ca(2+) has an inhibitory effect which increases with ion concentration.

CONCLUSION

The extracted enzyme belongs to the exo type of amylases and is classified as a β-cyclodextrin glycosyltransferase since it generates mainly β-cyclodextrin from starch. It exhibits high thermal stability and a broad range of pH stability, making it a promising prospect for industrial and food applications.