MTCC Strains Research Articles

Analysis of the main bioactive compounds from Ocimum basilicum for their antimicrobial and antioxidant activity.

The interest in bioactives especially from botanicals to treat vancomycin-resistant enterococcal (VRE) infections is increased. Many species of Ocimum have a long history in folk medicinal and food industries. Nevertheless, their bioactive compounds remain unexplored. This study is aimed to assess the antimicrobial and antioxidant activity of basil leaf extract prepared using ethanol, methanol, and water. The ethanol and methanol extract have all the phytochemicals (alkaloids, flavonoids, phenolic compounds, tannins, saponins, quinones, carbohydrates, and proteins) except steroids and terpenoids. In addition to steroids and terpenoids, tannin was also absent in the aqueous extract. Total phenolic and flavonoid content was high in ethanol and followed by methanol and aqueous extract. Similarly, ethanol and methanol extract showed strong antimicrobial activity against VRE and MTCC strains at a concentration of 20mg/mL than aqueous extract. Among the 10 indicators, Staphylococcus aureus is highly susceptible to ethanol extract at a concentration of 8mg/mL and followed by other MTCC strains. Vancomycin-resistant enterococci pathogens were inhibited at the minimum inhibitory concentration of 14, 16, and 20mg/mL of ethanol, methanol, and aqueous extract. Further, on the basis of determining the absorbing material (nucleic acid and protein) at 260nm and scanning electron microscopic, it was confirmed that the loss of cell membrane integrity and cell membrane damage were the effective mechanisms of plant extract antimicrobial activity. All three solvents have shown remarkable antioxidant activity. Gas chromatography-mass spectrometry analysis of basil leaves ethanol extract identified 19 compounds with various therapeutic and food applications.

Bio-inspired green fabrication of silver nanoparticles (AgNPs) using aqueous leaves extract of Ipomoea carnea Jacq. To tackle multiple drug resistance MTCC bacterial strains

AgNPs are employed in several applications, and we used Ipomoea carnea aqueous leaves extract to enhance the metal nanoparticle synthesis process. This study suggested that aqueous extract from I. carnea leaves can reduce silver nitrate (AgNO3) and act as a stabilizing and capping agent. The specific Plasmon resonance (SPR) was found between 390-410 ​nm in a UV–Vis spectrophotometer. Field Emission Scanning Electron Microscope (FE-SEM) and X-ray diffraction (XRD) analysis confirm the size between 11.21-46.90 ​nm with spherical face-center-cubic (FCC) crystals. Additionally, the antibacterial activity of synthesized AgNPs was also evaluated against four standard bacterial pathogens i.e. Klebsiella pneumoniae (MTCC 432), Staphylococcus aureus (MTCC 1144), Streptococcus pneumoniae (MTCC 655), and Pseudomonas aeruginosa (MTCC 2474) and Brine shrimp lethality assay (BSLA) was used to check the toxicity. Synthesized AgNPs were found significantly effective against all MTCC strains with a 1359.03 ​ng/mL LC50 value.

Myco-Facilitated Biosynthesis of Nano-Silver From Wasp Nest Fungus, Paecilomyces variotii, and Its Antimicrobial Activity Against MTCC Strains.

The utility of fungi as stabilizing and reducing agents in the biogenic synthesis of silver nanoparticles is striking due to the production of large quantities of biomolecules of minute toxic residuals. During the current study, sunlight- and dark-assessed silver nanoparticles were synthesized from wasp nest fungus, Paecilomyces variotii, at different pHs. Synthesized silver nanoparticles (AgNPs) at 6 pH were found to be more prominent than at 7 and 8 pHs. AgNPs were within the 20- to 90-nm range and were polygonal and elongated in shape. FTIR spectra of light-mediated AgNPs showed diverse transmittance bands than the silver nanoparticles synthesized in the dark. The synthesized AgNPs were found with diverse antimicrobial activities against pathogenic MTCC bacterial strains, i.e., Staphylococcus aureus, Vibrio parahaemolyticus, Escherichia coli, Shewanella putrefaciens, and fungus, Candida albicans. Aqueous filtrate and filtrate-mediated AgNPs combined with methanol solvent extract of yeast extract manitol broth (YEMB) had more inhibitory effects on all bacteria and Candida albicans. Furthermore, the combined effect of AgNPs and methanol solvent extract from YEMB culture filtrate was found more effective against E. coli, while AgNPs combined with methanol solvent of aqueous filtrate had inhibitory effects on E. coli and Candida albicans.

Antibacterial Activity and Time-kill Assay of Terminalia catappa L. and Nigella sativa L. against Selected Human Pathogenic Bacteria

The current investigation aims to test the susceptibility of human pathogenic clinical isolates and MTCC strains to leaf and seed extracts of Terminalia catappa and Nigella sativa. Disc diffusion assay, micro dilution assay and minimum Bactericidal Concentration investigated the susceptibility of bacteria to the test extracts. The active extract was subjected to phytochemical screening, separation of the phytochemicals by Thin Layer Chromatography, bioactivity guided assay and Time- kill assay. Acetone and methanol extracts of T.catappa revealed, significant inhibition of clinical origin Staphylococcus aureus followed by Proteus vulgaris and the MTCC strains Staphylococcus aureus, Salmonella typhi, Pseudomonas aeroginosa and Bacillus subtilis. Nigella sativa inhibited the growth of clinical origin Staph.aureus and MTCC strain of Staph.aureus, Salmonella typhi and B.subtilis. Minimum inhibitory concentration for all the test bacteria was reported in the range of 5000μg/ml to 9 μg/ml in T. catappa extract. Most sensitive being the clinical isolate Staph. aureus and Proteus vulgaris. The bactericidal concentration for the test bacteria was found to be between 5000μg/ml and 625μg/ml. Phyto-chemical analysis of leaf extracts of T. catappa found to have dominated by polyphenols (Terpenoids, steroids, flavonoids, flavones, saponins and tannins) and N.sativa extracts recorded the presence of alkaloids, proteins and oils and fats. TLC profiling of the acetone extract revealed many antibacterial active bands. Bands having Retention factor 0.47 and 0.52 were active against the test bacteria. Time kill assay of the acetone extract of T. catappa were carried out for the first time. The extract exhibited dose dependent bactericidal and bacteriostatic activity against the clinical isolates.

Molecular characterization of indigenous entomopathogenic fungus Beauveria bassiana, isolate and its virulence to Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae)

A fungal culture was isolated with a view to evaluate its potentiality for an effective pest management programme. The fungal culture was characterized at molecular level by using rDNA ITS universal primer. The fungal culture was identified as Beauveria bassiana (Bals.) Vuill. and the ~ 550 bp rDNA-ITS sequence was submitted to the Gene bank and obtained accession number as KR855715. The biological parameters of KR855715 were compared with MTCC strains of Beauveria bassiana (Bals.) Vuill and evaluate its efficacy against sixth instar of Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae), a major stored grain pest of rice under laboratory condition at temperature 30 ± 1 °C and relative humidity 85–90 %. The biological parameters and efficacy of all these strains were tested at different concentrations viz.., 1 × 107to 1 × 109 conidia/ml. Among these strains, KR855715 showed the highest conidial density (8.13 × 107 conidia/ml) at concentration of 1 × 107 conidia/ml. However, the germination (83.68 %), and mortality (60.00 %) was found to be highest at concentration 1 × 109 conidia/ml.

Green synthesis of silver nanoparticles using methanol extract of Ipomoea carnea Jacq. to combat multidrug resistance bacterial pathogens

Silver nanoparticles (AgNPs) are employed in a wide range of applications; in this study, we improved the AgNPs manufacturing method using I. carnea methanol leaves extract. We noticed that phytochemicals from I. carnea are capable to reduce silver nitrate and can also act as a capping and stabilizing agent. Between 408 and 412 ​nm, UV–Vis spectrophotometer absorption spectra (SPR peaks) were discovered. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FE-SEM) analyses revealed that the synthesized AgNPs were spherical face-center-cubic (FCC) crystals with 32.99 ​nm average particle size. Furthermore, the antibacterial activity of AgNPs was screened against four bacterial pathogen strains, namely Streptococcus pneumoniae (MTCC 655), Staphylococcus aureus (MTCC 1144), Pseudomonas aeruginosa (MTCC 2474), and Klebsiella pneumoniae (MTCC 432), and toxicity was determined using the Brine shrimp lethality assay. With an LC50 value of 1600.66 ​ng/mL, synthesized AgNPs were shown to be very effective against all MTCC strains.

Antimicrobial and Antibiofilm Effect of Cranberry Extract on Streptococcus mutans and Lactobacillus acidophilus: An In Vitro Study.

ABSTRACTBackgroundNature has been a source of medicinal treatments since millennia and plant-based systems continue to play an essential role.AimTo study the antimicrobial and antibiofilm effect of cranberry on Streptococcus mutans and Lactobacillus acidophilus.Materials and methodsThe ethanolic extract of cranberry was tested against standard MTCC strains of S. mutans (MTCC 25175) and L. acidophilus (MTCC 8129) for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The time kill assay was performed to check the time-dependent bactericidal effect of the cranberry extract on microorganisms. Percentage of cell adhesion and biofilm inhibition of the dental microorganism at various doses of cranberry extract was measured by a spectrophotometer and biofilm morphology characteristics were observed under scanning electron microscopy. All the tests were carried out in triplicates. Data were computed in the SPSS software and mean/SD was determined. The results are presented in a descriptive manner; Kruskal–Wallis analysis of variance (ANOVA) and the Friedman's test were applied for comparative evaluation of the groups. p value <0.05 was considered statistically significant.ResultsThe results showed that MICs of cranberry extract against S. mutans and L. acidophilus are 12.5 mg/dL and 6.125 mg/dL, respectively, and MBCs are 25 mg/dL and 12.5 mg/dL, respectively. A significant decrease in the biofilm formation and cell adhesion of microorganisms at MIC (50%) and MBC (70%) was observed as compared to control as observed under a spectrophotometer and a scanning electron microscope.ConclusionThis study has identified bactericidal, bacteriostatic, and antibiofilm effects of cranberry extract against S. mutans and L. acidophilus in a time-dependent and dose-dependent manner.How to cite this articleSinghal R, Patil P, Siddibhavi M, et al. Antimicrobial and Antibiofilm Effect of Cranberry Extract on Streptococcus mutans and Lactobacillus acidophilus: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):11–15.

Antimicrobial activity and phytochemical screening of Ocimum americanum L extracts against pathogenic microorganisms

The aim of the present study is to assess the antimicrobial activities of various leaf extracts of Ocimum americanum were tested against pathogenic microorganisms. Preparation of different extracts viz., aqueous, acetone, ethyl acetate and methanol through soxhlet extraction method. Various extracts were investigated against MTCC strains of Bacillus cereus, Clostridium penfrigens, Klebsilla pnemoniae, Salmonella paratyphi, Candida albicans and Aspergillus niger by agar well diffusion and disc diffusion methods. Minimum inhibitory concentration (MIC), Minimum Bactericidal/Fungicindal Concentration (MBC/MFC) were determined through micro dilution method. Elucidation of phytochemicals and functional groups were observed by HPLC and FT-IR respectively. Ethyl acetate leaf extract of O.americanum showed significant antimicrobial activity against the all tested pathogens in agar well diffusion method in which B.cereus (17 mm) was observed high zone of inhibition. Whereas lowest inhibition was observed in aqueous extract against C.pentrigens (7 mm). The ranges of MIC values from 0.78 μg/ml to 50 μg/ml and MBC/MFC 1.56 μg/ml to 50 μg/ml were observed. Phytochemicals such as alkaloids, steroids, saponins, flavonoids, tannins, terepenes, phenolic compounds cardiac glycosides were detected. Saponinns, flavonoids, tannins, phenolic compounds were observed in only ethyl acetate leaf extracts. Functional group of the leaf extracts was exhibited by FTIR and HPLC analysis of the ethyl acetate leaf extract was elutated at six peaks. Based on the results we concluded that ethyl acetate leaf extract of O.americanum has proved to be potentially effective than the other extracts. Therefore, ethyl acetate leaf extract of O.americanum could act as antimicrobial agent and further studies are recommended for isolation of compounds and toxicological studies.

Lutein: A potential antibiofilm and antiquorum sensing molecule from green microalga Chlorella pyrenoidosa

The increasing resistance of Pseudomonas aeruginosa towards antimicrobial agents has been a major cause for the escalation of untreatable diabetic foot ulcer cases around the globe. This demands research towards alternative natural products that inhibit biofilm formation by P. aeruginosa. The study focuses on enhancing as well as understanding the anti-biofilm property of lutein from Chlorella pyrenoidosa against MTCC strain of P. aeruginosa PAO1. C. pyrenoidosa was subjected to nutrient starvation (N−, S− and P−) and their growth, biomass, chlorophyll pigments and total carotenoids were estimated. Lutein extracted from nutrient starved C. pyrenoidosa were quantified using High Performance Liquid Chromatography (HPLC) and also used for quantification of biofilm formation, cell surface hydrophobicity (CSH), extracellular polymeric substances (EPS) and pyocyanin degradation. The results showed 20 μg/mL concentration of lutein showed maximum inhibition and degradation of biofilm formation, pyocyanin production, Cell Surface Hydrophobicity Extracellular Polymeric Substances, when compared to other concentrations. Azithromycin was used as a standard drug to compare the efficiency of lutein as a potential antibiofilm compound. Docking studies confirmed the interaction of lutein with the four proteins – LasI, LasR, RhlI and RhlR, involved in the quorum sensing mechanism during biofilm formation. Among them, RhlI protein was found to strongly interact and LasI exhibiting the least interaction with lutein. Gene expression analyses of las and rhl genes in P. aeruginosa PAO1 revealed a significant down regulation of both the genes in the cultures treated with different concentrations of lutein. Therefore, it can be understood that lutein is an effective antibiofilm agent and can be used in combination with generic drugs that are used for treating diseases such as diabetic foot ulcers, which are ineffective due to high biofilm forming capability of P. aeruginosa and other bacterial species.

Correction: Differential desulfurization of dibenzothiophene by newly identified MTCC strains: Influence of Operon Array.

[This corrects the article DOI: 10.1371/journal.pone.0192536.].

Antimicrobial, antibiofilm, and microbial barrier properties of poly (ε-caprolactone)/cloisite 30B thin films.

Development of antibacterial and antibiofilm surfaces is in high demand. In this study, nanocomposite of Poly (ε-caprolactone)/Cloisite 30B was prepared by the solvent casting method. The membranes were characterised by SEM, AFM, and FTIR. Evaluation of water uptake, antimicrobial, antibiofilm, and microbial barrier properties demonstrated a significant antimicrobial and antibiofilm activity against MTCC strain of Staphylococcus haemolyticus and strong biofilm positive Staphylococcus epidermidis of clinical origin at low clay concentrations. These membranes acted as an excellent barrier to the penetration of microorganism. These nanocomposites can have promising applications in various fields including packaging.

Herbal Formulation Against Dental Caries Causing Microorganisms Using Extracts of Stevia Rebaudiana Leaves (A Natural Sweetner)

Stevia Rebaudiana leaves have functional and sensory properties superior to those of many other high-potency sweeteners. Dental caries is an infectious microbiological disease that affects almost every human. There is a linear correlation of sugar consumption with dental caries in populations worldwide. Present invention was directed to design and develop Stevia based polyherbal formulation with enhanced performance in oral care as Stevia inhibits the growth of dental caries causing microorganisms. In the present study, twelve pure isolates grown on Snyder agar medium and five MTCC strains i.e. Streptococcus mutans, Staphylococcus aureus, Curvularia lunata, Escherichia coli and Bacillus subtilis were screened for antimicrobial activity through agar well diffusion method. Metabolites from plant leaves were extracted using six different solvents and investigated for phytochemical properties. Few cultures were found to be belonging to Staphylococcus species, Bacillus sp., Clostridium sp., Neisseria sp., and Escherichia. coli. On the basis of maximum zone of inhibition produced against cultures, diethyl ether extracts of plant were effective against bacteria and fungi, followed by petroleum ether and chloroform and finally minimum inhibitory concentration and minimum bactericidal concentration of extracts were performed. The phytochemical screening of different extracts of Stevia showed the presence of various secondary metabolites. Herbal formulation prepared in diethyl ether extract displayed significant bioactivity against all twelve isolated cultures and standard cultures. The study holds importance as one needs to be familiarized with alternatives to sugar and type of food products that are available with substitute sweetening agents, as we have the responsibility to reduce the incidence of dental caries by emphasizing the role of sugars in caries formation. Keywords: Stevia rebaudiana, dental caries, herbal formulation, antimicrobial, phytochemical, snyder media.

Synthesis, Characterization and Biological Evaluation of Mononuclear Dichloro-bis[2-(2-chloro-6,7-substituted Quinolin-3-yl)-1H-benzo[d]imidazole]Co(II) Complexes

A series of Co(II) complexes 3 ¢ a-g of 2-(2-chloro-6,7-substituted quinolin-3-yl)-1 H -benzo[ d ]imidazole ligands 3a-g were prepared and characterized by various spectroscopic and physico-chemical methods viz . FT-IR, ESI mass, 1 H NMR, 13 C NMR and UV-Visible spectroscopy, Thermogravimetric analysis, Magnetic susceptibility, Molar conductance and Elemental analysis. The 2-(2-chloro-6,7-substituted quinolin-3-yl)-1 H -benzo[ d ]imidazole ligands 3a-g have been synthesized by cyclocondensation of benzene-1,2-diamine with 2-chloroquinoline-3-carbaldehydes by using ceric ammonium nitrate as a catalyst in presence of hydrogen peroxide as an oxidant. The structures of all ligands were confirmed by IR, Mass, UV-Visible, 1 H NMR and 13 C NMR spectroscopy. All ligands 3a-g and their Co(II) complexes 3 ¢ a-g were screened for their in vitro antimicrobial activity using twofold serial dilution technique against standard MTCC strains of two Gram-positive Staphylococcus aureus and Streptococcus pyogenes , two Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria and three Candida albicans , Aspergillus niger and Aspergillus clavatus fungus in comparison with standard drugs. All ligands 3a-g and complexes 3 ¢ a-g also evaluated for antimycobacterial activity against standard Mycobacterium tuberculosis H 37 Rv strain. DOI: http://dx.doi.org/10.17807/orbital.v7i2.530

Rhinacanthin production from hairy root cultures of Rhinacanthus nasutus (L.) Kurz

Rhinacanthus nasutus (L.) Kurz (family Acanthaceae) produces several important bioactive molecules. Its leaves and roots were widely used in traditional systems of medicine for the treatment of cancer and other serious diseases. In the present study, the contents of three potent natural naphthoquinone esters, rhinacanthin (RC)-C, RC-D, and RC-N, were evaluated in R. nasutus hairy root cultures. Hairy roots were induced from leaves, stems, and cotyledons following transformation with Agrobacterium rhizogenes (MTCC Strain No. 532). The highest frequency (73%) of hairy root induction was observed with cotyledons. Four media (½ Murashige and Skoog [MS], MS, Schenk and Hildebrandt medium, and Woody Plant Medium) were then compared for their effects on hairy root growth and RC production. The transgenic status of hairy roots was confirmed by PCR analysis and Southern hybridization analysis. A time course study revealed that the highest hairy root biomass (0.89 g/flask dry weight [DW]) and RC contents (RC-C, 3.8 mg/g DW; RC-D, 0.43 mg/g DW; and RC-N, 0.18 mg/g DW) were observed following culture on MS medium 6 wk after culture initiation. The root biomass (1.41 g DW/flask) and RC contents (RC-C, 4.4 mg/g DW; RC-D, 0.69 mg/g DW; and RC-N, 0.21 mg/g DW) were further increased by the use of 4% sucrose. The growth and RC production from hairy roots of R. nasutus demonstrated in the present study may offer an effective and reliable alternative for the exploitation of this medicinal plant.

A Cross Sectional Study on Prevalence of Antibiotic Resistance and Role of Efflux Pumps in Fluoroquinolone Resistance by using Efflux Pump Inhibitors in Isolated Cultures from Poultry, Dairy Farms and MTCC Strains from Reservoirs

Aims: Emergence of antibiotic resistance in bacterial strains has always remained a crucial concern. Mutations in antibiotic target sites, over expression of efflux pump are the major modes of development of bacterial antibiotic resistances. The present study was conducted to determine antibiotic resistance and role of efflux pumps in fluoroquinolone resistance by using efflux pump

Biodegradation and bioelectricity generation by Microbial Desalination Cell

This study highlights the application potential of Microbial Desalination Cell in effective bioremediation of dye house effluent by biodecolourisation of industrial dyes. The study showed, for the first time, that the dye house effluent could be used as an organic substrate in MDC, achieving biodecolourisation of effluent along with considerable desalination and power production. Utilization of these wastes in MDC can protect the environment from dye-containing wastewater contamination and the treated water can be reused for other purposes. Two bacterial strains, a novel isolate Bacillus subtilis moh3 and a MTCC strain Aeromonas hydrophila subsp. hydrophila 8049 were used for decolourisation of two model dyes-Malachite Green (C.I.42,000) and Sunset Yellow (C.I.15,985). Decolourisation of dyes by these cultures was studied in batch cultures and optimized the growth conditions. The same cultures when used in Microbial Desalination Cell, achieved complete biodecolourisation along with considerable desalination (62.2 ± 0.4% and 57.6 ± 0.2%) and power production.

Pharmaco-Phylogenetic Investigation of Micromeria biflora Benth and Citrus reticulata Blanco

Bacterial diseases, diarrhoea, cholera, typhoid and dysentery mainly originate through consumption of bacterial contaminated water. Comparative in-vitro antimicrobial activity of some essential oils (EOs) against a few water borne bacterial diseases are reported. The minimum inhibitory concentrations (MIC) of essential oil of Micromeria biflora Benth for Escherichia coli (ATCC-25922), E. coli (MTCC-723), Shigella dysenteriae (ATCC-23513) Salmonella typhimurium (MTCC-98) respectively was 0.172, 0.308, 0.178, 0.202 mg/ml but in case of Vibrio cholerae (MTCC-3906) the oil was found ineffective. The essential oil of Citrus reticulata Blanco had MIC against E. coli 2.60 mg/ml, V. cholerae 8.06 mg/ml, S. dysenteriae 2.99 mg/ml, S. typhimurium 5.18 mg/ml, but the oil has no efficacy against E. coli (MTCC). Further, due to synergistic activity, the oils were found to be more effective against MTCC strain of E. coli and V. cholerae at MIC of 0.15 and 0.14 mg/ml respectively. The phylogenetic evaluations of the pathogens were carried out with help of ClustalW computer program.

Comparative study on production of α-Amylase from Bacillus licheniformis strains

Alpha amylase (α-1, 4-glucan-glucanhydrolase, EC 3.2.1.1), an extracellular enzyme, degrades α, 1-4 glucosidic linkages of starch and related substrates in an endo-fashion producing oligosaccharides including maltose, glucose and alpha limit dextrin (7). The present study deals with the production and comparative study of production of α-amylase from two strains of Bacillus licheniformis, MTCC 2617 and 2618, by using four different substrates, starch, rice, wheat and ragi powder as carbon source by submerged fermentation. The effect of varying pH and incubation temperature, activator, inhibitor, and substrate concentration was investigated on the activity of α-amylase produced by MTCC strain 2618. The results shows that the production of the α-amylase by the B.licheniformis strain MTCC 2618, using four different substrates were found to be maximum (Starch 3.64 IU/ml/minutes, Rice powder 2.93 IU/ml/minutes, Wheat powder 2.67 IU/ml/minutes, Ragi powder 2.36 IU/ml/minutes) on comparing the enzyme production of two strains. It was also observed that the maximum production was found on the 3(rd) day (i.e. 72 hr) and characterization of crude enzyme revealed that optimum activity was at pH 7 and 37°C.

Production and Evaluation of Chitosan from Aspergillus Niger MTCC Strains.

Three different Aspergillus Niger MTCC strains (872, 1785 and 2208) were used for the production of chitosan. Multivariate growth mediums in varying incubation periods were analyzed for the production. The produced chitosan was characterized by its physical appearance, moisture content (by means of gravimetric method), percentage of ash and solubility (through the Association of Official Agricultural Chemists (AOAC) methods) and also the degree of deacetylation (with Infrared spectroscopy). The infrared (IR) spectrum of produced fungal chitosan shows strong similarity with the IR spectrum of commercial chitosan. Our experimental results concluded that the maximum yield of chitosan (26.1%) was obtained from Aspergillus niger MTCC 2208 grown in supplemented Potato Dextrose Broth (PDB) medium, incubated at 30°C for 120 h in 180 rpm. The antimicrobial activity of produced chitosan was tested against five bacteria by Disc diffusion technique, which confirmed that chitosan have minimal antimicrobial activity.

Comparative study on production of a-Amylase from Bacillus licheniformis strains

Alpha amylase (α-1, 4-glucan-glucanhydrolase, EC 3.2.1.1), an extracellular enzyme, degrades α, 1–4 glucosidic linkages of starch and related substrates in an endo-fashion producing oligosaccharides including maltose, glucose and alpha limit dextrin (7). The present study deals with the production and comparative study of production of α-amylase from two strains of Bacillus licheniformis, MTCC 2617 and 2618, by using four different substrates, starch, rice, wheat and ragi powder as carbon source by submerged fermentation. The effect of varying pH and incubation temperature, activator, inhibitor, and substrate concentration was investigated on the activity of α-amylase produced by MTCC strain 2618. The results shows that the production of the α-amylase by the B.licheniformis strain MTCC 2618, using four different substrates were found to be maximum (Starch 3.64 IU/ml/minutes, Rice powder 2.93 IU/ml/minutes, Wheat powder 2.67 IU/ml/minutes, Ragi powder 2.36 IU/ml/minutes) on comparing the enzyme production of two strains. It was also observed that the maximum production was found on the 3rd day (i.e. 72 hr) and characterization of crude enzyme revealed that optimum activity was at pH 7 and 37°C.