Asian Journal of Microbiology and Biotechnology
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EVALUATION OF ACTIVITY AND MASS SPECTROMETRIC CHARACTERIZATION OF TWO PARTIALLY PURIFIED THERMO-TOLERANT LIPASE FRACTIONS FROM THE FUNGAL CULTURE OF Aspergillus niger GN1
No full textFungal infestations of groundnut seeds were screened for thermo-tolerant lipases with stability over a wide pH range and temperature, desirable for industrial applications. DNA sequencing of ITS 1, 5.8S and ITS 2 regions indicated the isolate closer to Aspergillus niger with 99% identity and therefore designated as A. niger GN1 in this study. The pellet obtained from culture extract subjected to 65% ammonium sulphate precipitation was suspended in Tris-buffer and assayed for lipase activity. Two fractions of lipase (1 and 2) could be extracted at pH 4 and pH 9 respectively. Both lipase 1 and 2 fractions were characterized by LC-MS/MS spectroscopic analysis. The relative and residual activities of the enzyme fractions were high in the temperature range of 60 – 80°C and over a pH of 4 & 8 for lipase 1 and 2-6 for lipase 2 fractions. LC-MS/MS confirmed the presence of Lipase 1 (~32 kDa) and Lipase 2 (~30 kDa) fractions with 4 and 2 unique peptides respectively
FAST FOOD PACKING WASTE IN JORDAN: OPPORTUNITIES FOR SUSTAINABILITY
No full textSustainable waste management requires innovative ways to reduce the carbon footprint and make use of the renewable resources available. Packaging although necessary, gives rise to waste which forms 34% of Jordan’s solid wastes. It adds to the environmental degradation and requires urgent action. In order to reduce the carbon foot print of fast food packaging waste in Jordan an innovative, sustainable and green solution is the ‘green banana’ project. The idea is to use the abundantly available leaves of banana and fig trees for food wrapping, serving, packaging and presentation in fast food outlets in Jordan. The first point of focus of the “leafy” initiative will be the local fast food outlets in Amman that use non-biodegradable plastic and polystyrene food containers and serve typical fast foods like ‘shawerma’, ‘homus’, ‘foul’, ‘falafel’ and other sandwiches. The aim is to bring awareness to the fast food industry in Jordan of the energy conservation and cost saving attributes of adopting this leafy solution for food serving and packaging. The purpose is also to initiate a policy change of banning single use plastic and polystyrene containers for fast food in Jordan
PHYSICOCHEMICAL AND MICROBIOLOGICAL FEATURES OF THE STORED CITRIC ACID TREATED ORANGES IN NIGERIA
No full textIn Nigeria, poor post-harvest handling of agricultural products contributes to increasing spoilage of oranges; hence, the need for the present strategy to enhance its shelf-life. The study evaluates, the physicochemical and microbiological features of peeled and unpeeled oranges, treated with different concentrations of citric acid and stored under room (hawking) and refrigeration temperatures for 16 days. Citric acid treatment of oranges showed significant effect (P≤0.05) on the acidity and enterobacterial count while the nature of samples significantly affected the pH, brix, total bacterial, yeasts and enterobacterial counts. Furthermore, the storage temperature significantly affected all the parameters. The spoilage organisms were identified as Aspergillus niger, Macrophomina species, Bacillus subtilis and Chryseomonas luteola. The citric acid improved the shelf-life of oranges sold in Nigerian open markets, from 10 to 15 days (unpeeled) and from 2 to 3 days (peeled) at hawking temperature. Two strains of Aspergillus niger and one species of Macrophomina were isolated from spoilt oranges and both demonstrated ability to produce pectinase, but the A. niger strains were better. The optimal temperature of pectinases from the A. niger strains was 50oC and optimum pH range of 4-5, while that from Macrophomina species was 40oC and pH 9 respectively. The crude pectinases from the Aspergillus niger strains and Macrophomina species were activated by Ag3+ and Na+, whereas Fe3+ inhibited the enzymes from all three fungal sources. A 2-minute infusion of oranges in citric acid solution is recommended for shelf life elongation of oranges hawked at ambient temperature in open markets. Moreover, based on their optimal pH, pectinases from A. niger will be a good raw material in the industrial production of wine, vegetables, purees and pastes, while the alkaline pectinases from Macrophomina sp. will be useful in waste treatment
PURIFICATION AND CHARACTERIZATION OF EXTRACELLULAR LIPASE ENZYME FROM Aspergillus costaricaensis CBS115574
No full textIn the present study, the lipase of alkaline nature obtained from the previously isolated strain Aspergillus costaricaensis CBS115574 was characterized and purified out using ammonium sulfate precipitation and chromatographic techniques on Diethylaminoethyl A-50 and Sephadex G-100. The purified lipase has the molecular weight of ~50 kDa which was determined by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Zymography by using the phenol red along with the purification fold of 6.63 and specific activity of 31.73 IU/mg after the gel filtration chromatography. Lipase was found to be stabilized at the pH 7 (122.68 IU/g/min) and at the temperature of 80ºC (141.36 IU/g/min) with its optimal activity at pH 8 and temperature 50ºC. The Km and Vmax value for extracellular lipase were reported to be 29.62 mM and 74.07 IU/ml with their higher tolerance to glycerol (organic solvent), tween 80 (detergent), Ethylene diamine tetra acetic acid (activator & inhibitor), hydrogen peroxide (oxidizing & reducing agent) and sodium chloride (metal ions) with lipase activity of 106.74 IU/g/min, 84.53 IU/g/min, 108.06 IU/g/min, 97.17 IU/g/min and 118.7 IU/g/min. The above results suggested that A. costaricaensis CBS115574 lipase found a suitable position for application in different types of industries
SOLID STATE FERMENTATION MEDIA OPTIMIZATION FOR PRODUCTION OF α-Amylase BY Aspergillus sydowii IMI 502692
No full textAspergillus sydowii IMI 502692 isolated from cassava processing agro-enterprise waste dump site was cultivated by Solid-State Fermentation of cassava root fibre (5 g) buffered with basal medium (20 ml) made up of % (w/v): CaCl2.2H2O, 0.05 g, (NH4)2SO4, l g; KH2PO4, 0.3 g; MgSO4.7H2O; 0.05 g. The culture condition for α-amylase production by A. sydowii IMI 502692 was optimized. Organic nitrogen (cow blood meal) gave maximum α-amylase yield (1.462 Uml-1) while the effect of varying concentration of cow blood meal shows that 0.3% (w/v) was optimum for α-amylase production with 1.602 Uml-1 Tween 20 0.5% (v/v) induced amylase production most with the activity of 1.626 Uml-1. The initial based medium pH of 6.0 gave maximum enhancement of α-amylase activity (2.050 Uml-1). Sulphate salts of Ca2+ and Mn2+ 5 mM induced α-amylase production while that of Sr2+, Fe2+, Zn2+ and N12+ repressed the enzyme production. α-Amylase production kinetics in solid-state fermentation of the buffered cassava root fibre revealed an optimum α-amylase activity (1.910 Uml-1) occurring at day 3 with a corresponding culture pH of 3.645 Biomass accumulation rose from day 1 (0.010 g) and progressed through the period of fermentation to day 5 (0.303 g)
In vitro REGENERATION OF SOME ETHIOPIAN MAIZE (Zea mays L.) LINES AND VARIETIES FROM IMMATURE EMBRYOS THROUGH CALLUS INDUCTION
No full textMaize is an important food crop in Ethiopia. Among major factors contributing to the low productivity of maize in Ethiopia include, absence of improved varieties and significant yield reduction due to high incidences of biotic and abiotic stresses. Success in genetic transformation requires efficient in vitro regeneration protocols. However, inadequate information is available on in vitro regeneration of maize varieties/lines developed for Ethiopian climate. Therefore, this study was initiated to optimize the in vitro regeneration protocols for some inbred lines and open pollinated maize varieties from immature embryos. Immature embryos evaluated for their ability to form callus were cultured in N6 medium and incubated at room temperature in dark to initiate callus. Embryogenic calli were transferred from callus maintenance medium to embryo maturation medium supplemented with 2 mg/l glycine, 1 mg/l NAA and different levels of sucrose (55, 60, 65 or 70 g/l). Matured somatic embryos were subcultured in shoot regeneration medium consisting of MS medium supplemented with 2 mg/l glycine, 2% sucrose and different levels (0, 0.1, 0.2 and 0.3 mg/l) of BAP. Roots were induced by subculturing individual shoots on half strength MS medium supplemented with 2 mg/l glycine, 2% sucrose and different levels (0, 0.1, 0.2 and 0.3 mg/l) of NAA. Immature embryos harvested in between 16-20 days after pollination, depending on the variety responded better than early harvested immature embryos for average callus induction. Better plant regeneration was obtained at basal (hormone free) MS medium. Better root formation was at 0.1 mg/l NAA with average of 2.82- 4.50 roots per shoot. Regenerated plantlets were successfully acclimatized in greenhouse and field conditions with survival rates of 83.7% and 75.6% respectively. This study established a regeneration scheme for maize lines/ varieties via somatic embryogenesis from immature embryos and high performing maize verities/ lines were identified
MOLECULAR METHODS FOR DIAGNOSING Candida INFECTION: A COMPARATIVE STUDY AND REVIEW OF LITERATURE
No full textIn current time, invasive fungal infections have become a major threat for the immunocompromised hospitalised patients. Also, healthy individuals are much prone to the commensal yeasts of the oral cavity. Different surveys and studies have recorded increased rate of Candida albicans and non-albicans such as of C. glabrata, C. tropicalis, C. guilliermondii, C. dubliniensis, C. parapsilosis and C. krusei in local and systemic fungal infections. Thus, a rapid and correct identification of different Candida species plays an important role in diagnosis and antifungal therapy against candidiasis. The conventional diagnostic methods, such as histopathology and culture which are based on morphological and physiological attributes are low in sensitivity and also not very accurate. Development and standardisation of various molecular techniques (both PCR and non-PCR based) have proved to be promising approach for correct and quicker identification of Candida species. More and more technical development in these methods can bring their widespread clinical use with much more ease in coming days. The purpose of this review is to highlight the value, limitations and current state of different molecular approaches utilized for species level identification in Candida diagnostics
EFFECT OF pH STABILITY ON ALPHA AMYLASE EXTRACTED FROM Aspergillus niger ON STARCH FROM LOCAL RICE IN GHANA
No full textBackground: Alpha-amylases are one class of the amylase enzymes extensively synthesized in plants, animals, and microbes. They have been generally used in many industrial applications in a wide range of industrial processes such as food, pharmaceutical and detergent industries.
Due to their high catalytic and thermos stability property according to Yadav, fungal amylases are effectively applied in a wide range of industrial processes. These enzymes are affected by pH, temperature and/or substrates concentration.
Aim: This study aimed at determining the stability of alpha amylase from Aspergillus niger with varied pH conditions.
Methods: The kinetic stability of the enzyme was measured by determining its half-life (t1/2) and inactivation rate constant (kd) where pH was varied from 4.5 to 8.5 along with temperature from 50°C to 90°C. The inactivation rate constant was determined from the equation while the t1/2 was determined from=.
Results: The activation energy of inactivation was determined from the Arrhenius plot of inactivation. The protein concentration was estimated to be 2.57mg/ml by the Biuret method. The amylase isolated was thermos table with an optimum temperature of 70°C, optimum pH of 6.5 and an optimum substrate concentration of 0.26%. The Km was 0.13% while the Vmax was 1.0×10-4g/ml. The kd values ranges from 0.0780 to 0.0814 min-1 while the t1/2 values ranges from 8.51 to 8.78min and the results observed for pH 4.5, 6.5, 7.0, and 8.5 are 4.821 x102J/mol, 9.342 x102J/mol, 28.025 x102J/mol and -9.362x102 J/mol respectively.
Conclusion: The stability of the enzyme is decreased by pH variation in the order pH 8.5 < pH 4.5 < pH 6.5 < pH 7.0 showing that the enzyme is stable in alkaline and acidic medium than in a neutral pH. The optimum substrate at which the reaction rate is independent of the substrate concentration was determined to be 0.26% (0.0026 g/ml
THE EFFECT OF CATECHIN, TANNIC AND GALLIC ACIDS ON BIOFILM FORMATION IN Escherichia coli DEPENDS ON THE MEDIUM COMPOSITION
No full textCatechin, tannic and gallic acids belong to the most abundant nutritional plant polyphenols capable of modulating physiology of gut bacteria. The described modulation patterns vary from prebiotic/protective to anti-biofilm/antibacterial. Adequate interpretation of observed effects requires investigation of contributing factors. Apparently, applied dose and composition of the cultivation medium might be both essential for switching between planktonic and biofilm lifestyles. The aim of the present study was to study the effects of broad concentration range of catechin, tannic and gallic acids on pharmacodynamical parameters and biofilm formation in Escherichia coli BW25113 in minimal media M9 supplemented with glucose and LB broth. Here we showed the distinct modes of mass biofilm formation (BF) in Escherichia coli BW25113 in LB broth and M9 supplemented with glucose in the presence of polyphenols. BF was inhibited by 4 mg/ml catechin, tannic and gallic acids in LB, while in M9 tannic acid induced BF which correlated with no minimal biofilm prevention concentration (MBPC) found for tannic acid, while for gallic acid MBPC was 4 mg/ml. In both media minimal inhibitory concentrations (MICs) for tannic and gallic acids were 1 and 4 mg/ml, respectively, while minimal bactericidal concentration (MBC) was only found for gallic acid (4 mg/ml) in LB broth. In certain cases, the amount of cells undergoing biofilm formation was altered. Calculation of specific biofilm formation revealed absence of inhibiting effects for gallic acid, however stimulation by tannic acid was still present in both media
DIVERSITY OF MICROBES VIS-A-VIS Bacillus thuringiensis IN RICE FIELD SOILS OF NRRI, INDIA
No full textDifferent microbiome and Bacillus thuringiensis diversity and dynamics of field soils of sole rain fed rice, and deep/shallow water rice-fish cultivation systems of National Rice Research Institute was assessed to enrich knowledge on functionalities of active microbial guilds of aforementioned micro-ecologies. Diversity and dynamics (x105 cfu/g soil, approx.) of microbial guilds viz. heterotrophs (1.04-7.87), spore formers (0.37-0.99), Gram negative bacteria (0.87-9.44), asymbiotic N2 fixers (0.10-0.17), nitrifiers (0.04-0.38), denitrifiers (0.09-0.38), spore crystal formers (0.003-0.02), actinobacteria (0.004-0.005) and fungi (0.003-0.01), as well as, indices (0.07-0.19 x 10-2) of spore-crystal forming bacteria i.e. Bacillus thuringiensis (Bt) were highly diverse in rain fed rice and deep/shallow water rice-fish farming field soils. Four spore-crystal forming bacterial isolates viz. TB426 and 432 of rice field, and TB436 of deep water rice-fish and TB442 of shallow water rice-fish farming field soils were diverse in phenotypic characters, antibiotic/salt (6–11% NaCl) tolerance, crystal composition (bipyramidal but variable sizes) etc. The Bt isolates (Bts) had 62.10-76.87 kbp genomic DNA (gDNA) and single plasmid (24.33- 42.50 kbp). The Bts (TB 426/432) had 12-14 cellular proteins (9.88-540.7 kDa). Phenotypic identities of TB426 and 432 were Bacillus thuringiensis (Bt) var. galleriae, TB436 was Bt var. thompsoni/coreanensis and TB442 was Bt var. dendrolimus/sotto. The results proved structural and functional diversity of Bt population in NRRI rice soils of different micro-ecologies. The resident Bt with different toxin composition would be potent natural biocide and can be exploited for suppression of different rice field pests to sustain productivity