Production of β-glucanase enzyme from Penicillium oxalicum and Penicillium citrinum

Two Penicillium species namely, Penicillium oxalicum and Penicillium citrinum cultivated by solid surface fermentation method using rice bran homogenized with 0.5% (w/v) (NH4)2SO4 solution as nitrogen source and Whatman no. 1 filter paper (WFP1) as substrate for β-glucanase enzyme production medium were found to show a dense growth. Studies on the enzyme, using soluble cellulose (SC) and methyl cellulose (MC) as cellulose-glucan source and Somogyi titrimetric method, revealed optimum temperature for enzyme activity from the Penicillium species, ranging from 50 to 55°C and thermostability of up to 70°C after 15 to 30 min incubation in sodium phosphate buffer. It was found that the metal ions (0.5 to 5.0 M) namely: Zn2+, Cu2+ and Hg2+ did not enhance β-glucanase activity. Cu2+ ions reduced the enzyme activity slightly, Zn2+ ions had no effect, while Hg2+ completely inhibited β-glucanase activity. β-Glucanase can be produced from some fungal species locally using the abundant agricultural wastes (such as rice bran) as substrates.Key words: Fermentation, methylcellulose, metal inhibitors, soluble cellulose, Penicillium species

Antibacterial effects of Balanites aegyptiaca L. Drel. and Moringa oleifera Lam. on Salmonella typhi

The aqueous and organic leaves extracts of Balanites aegyptiaca and Moringa oleifera traditionally used for the treatment of infectious disease were tested for their activity against Salmonella typhiisolated from blood clot culture using the disc diffusion method. Extracts of B. aegyptiaca demonstrated higher activity (16 mm zone of inhibition) than those of Moringa oleifera (8 mm zone ofinhibition) at 100 mg/ml. Of the three solvents used, ethanolic extracts of both plants demonstrated the highest activity, while the aqueous extracts showed the least activity at 100 mg/ml. The activities ofthese plant extracts were comparable to those of antibiotics, ciprofloxacin, cotrimoxazole and chloramphenicol, commonly used for treating typhoid fever. The antibacterial activity appears toincrease when extracts of the two plants were used in combination at 100 mg/ml each (18 mm zone of inhibition). Preliminary phytochemical screening showed that both plant extracts contains saponins,tannins and phenols while only M. oleifera possesses alkaloids and B. aegyptiaca possesses anthraquinones. The antibacterial activities of the extracts on S. typhi was reasonably stable when treated at 4, 30, 60 and 100oC for 1 h, however it reduces significantly when the pH was altered towards alkalinity

Antimicrobial and toxicological activities of five medicinal plant species from Cameroon Traditional Medicine

<p>Abstract</p> <p>Background</p> <p>Infectious diseases caused by multiresistant microbial strains are on the increase. Fighting these diseases with natural products may be more efficacious. The aim of this study was to investigate the <it>in vitro </it>antimicrobial activity of methanolic, ethylacetate (EtOAc) and hexanic fractions of five Cameroonian medicinal plants (<it>Piptadeniastum africana</it>, <it>Cissus aralioides, Hileria latifolia, Phyllanthus muellerianus </it>and <it>Gladiolus gregasius) </it>against 10 pathogenic microorganisms of the urogenital and gastrointestinal tracts.</p> <p>Methods</p> <p>The fractions were screened for their chemical composition and <it>in vivo </it>acute toxicity was carried out on the most active extracts in order to assess their inhibitory selectivity.</p> <p>The agar well-diffusion and the micro dilution methods were used for the determination of the inhibition diameters (ID) and Minimum inhibitory concentrations (MIC) respectively on 8 bacterial species including two Gram positive species (<it>Staphylococcus aureus, Enterococcus faecalis)</it>, and six Gram negative <it>(Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Shigella flexneri, Salmonella typhi) </it>and two fungal isolates (<it>Candida albicans, Candida krusei)</it>. The chemical composition was done according to Harbone (1976), the acute toxicity evaluation according to WHO protocol and the hepatic as well as serum parameters measured to assess liver and kidney functions.</p> <p>Results</p> <p>The chemical components of each plant's extract varied according to the solvent used, and they were found to contain alkaloids, flavonoids, polyphenols, triterpens, sterols, tannins, coumarins, glycosides, cardiac glycosides and reducing sugars. The methanolic and ethylacetate extracts of <it>Phyllanthus muellerianus </it>and <it>Piptadeniastum africana </it>presented the highest antimicrobial activities against all tested microorganisms with ID varying from 8 to 26 mm and MIC from 2.5 to 0.31 mg/ml. The <it>in vivo </it>acute toxicity study carried out on the methanolic extracts of <it>Phyllanthus muellerianus </it>and <it>Piptadeniastrum africana </it>indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs.</p> <p>Conclusion</p> <p>These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents.</p> <p>Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine</p

Effect of Dettol&#174 on viability of some microorganisms associated with nosocomial infections

The efficacy of the liquid disinfectant Dettol® against nosocomial Staphylococcus aureus, Escherichia coli and Candida albicans was investigated. Use dilutions of the disinfectant were not immediatelylethal to the microorganisms, with the survival curves exhibiting an initial shoulder before exponential order of death. Tap water adversely affected the death rates and the decimal reduction times (DRT). The usefulness of the product and the implications of the adverse effect of tap water on the activity were discussed

In vitro assessment of antibacterial activity of bark extracts of Khaya senegalensis

In vitro antibacterial activity of aqueous, ethanol and acetone extracts of Khaya senegalensis were tested against Staphylococcus aureus, Streptococcus pyogenes, Salmonella typhi, Shigella dysenteriae, Klebsiella pneumoniae and Pseudomonas aeruginosa isolated from clinical specimen. The acetone extracts showed higher antibacterial activity compared to the aqueous and ethanol extracts. The minimum inhibitory concentration of acetone extracts was in the range of 6.5 to 12.5 mg/ml whilethe minimum bactericidal concentration ranges between 6.5 to 25.0 mg/ml. The antibacterial activity of the extracts was not significantly affected by heating at 100o C for 1 h but the activity was lost at pH 8.0

Efficacy of low-pressure foam cleaning compared to conventional cleaning methods in the removal of bacteria from surfaces associated with convenience food

BACKGROUND: Food borne illnesses and food poisoning are cause for concern globally. The diseases are often caused by food contamination with pathogenic bacteria due largely to poor sanitary habits or storage conditions. OBJECTIVES: Prevalence of some bacteria on cleaned and sanitised food contact surfaces from eight convenience food plants in Gauteng (South Africa) was investigated with the view to evaluate the efficacy of the cleaning methods used with such food contact surfaces METHODS: The microbial load of eight convenience food manufacturing plants was determined by sampling stainless steel food contact surfaces after they had been cleaned and sanitised at the end of a day's shift. Samples were analysed for Total Plate Count (TPC), Escherichia coli, Salmonella species, Staphylococcus aureus and Listeria species. RESULTS: Results showed that 59 % of the total areas sampled for TPC failed to comply with the legal requirements for surfaces, according to the Foodstuffs, Cosmetics and Disinfectants Act (< 100 cfu.cm(−2)). S. aureus and Salmonella were not detected, but Listeria was detected in 23 % and E. coli in 1.3 % of the samples. Fifty percent (50 %) of the plants applied conventional cleaning methods for cleaning and sanitation and 50 % used the low-pressure foam (LPF) method. There was significant difference (P ≤ 0.05) between the mean TPC values of the conventional cleaning method (14 358.82) compared to that of LPF method (2 386.51) but no significant difference (P > 0.05) in terms of Listeria species isolates obtained from both cleaning methods. The LPF method proved to be the superior cleaning option for lowering TPC counts. CONCLUSION: Regardless of cleaning method used, pathogens continued to flourish on various surfaces, including dry stainless steel, posing a contamination hazard for a considerable period depending on the contamination level and type of pathogen. Intensive training for proper chemical usage and strict procedural compliance among workers for efficient cleaning procedures is recommended