Investigation of the Effect of Initial Biomass on Nitrate and Phosphate Removal from Synthetic Wastewater by Selected Bacteria Isolates

Although nitrogen and phosphorus are important nutrients to the existence of living organisms, their presence in excessive amounts in wastewater could have detrimental effects to humans and other living organisms.  The present investigation was aimed at ascertaining the effect of initial biomass concentration on the nutrient removal efficiency of four bacterial species in synthetic wastewater under shaking flasks conditions. Four different initial biomasses [2.91 x 108 cfu/mL, 5.82 x 108 cfu/mL, 8.73 x 108 cfu/mL and 1.16 x 109 cfu/mL (Klebsiella sp.); 6.31 x 108 cfu/mL, 1.26 x 109 cfu/mL, 1.89 x 109 cfu/mL and 2.52 x 109 cfu/mL (Pseudomonas sp.); 1.75 x 108 cfu/mL, 3.49 x 108 cfu/mL, 5.24 x 108 cfu/mL and 6.98 x 108 cfu/mL (Lysinibacillus sp.), and 7.1 x 108 cfu/mL, 1.42 x 109 cfu/mL, 2.13 x 109 cfu/mL and 2.84 x 109 cfu/mL (Staphylococcus sp.)] were used for the study. For nutrient removal studies, the respective initial biomasses of the test isolates were inoculated into flasks containing the wastewater media. Aliquot samples were taken at the beginning of the study and every 24 h for 96 h for the estimation of growth rate, pH, phosphate and nitrate concentrations in the wastewater, using standard methods. The results revealed only slight phosphate decreases in the wastewater after the expiration of incubation. All the test isolates showed significant nitrate removal ability except the Lysinibacillus sp. After 96 h incubation 68.36 to 90.67 %, 91.80 to 95.29 %, 3.20 to 11.48 % and 86.77 to 94.33 % of nitrate was removed in the presence of the Klebsiella sp., Pseudomonas sp., Lysinibacillus sp. and Staphylococcus sp., respectively. The study was able to reveal the phosphate and nitrate removal ability of the isolates at the different initial biomasses used for the investigation. Keywords: Bacteria, wastewater, nutrient removal, phosphate, nitrat

Remediation of polluted wastewater effluents: hydrocarbon removal

The onset of the industrial revolution has led to a surge in the quantity of hazardous compounds that are released into the environment. These hazardous pollutants consist of a variety of hydrocarbons and other organic compounds that pose serious risks to humans, animals and the environment. The presence of hydrocarbons in wastewater effluents is due to a variety of sources, which include oil spillage, pesticides, urban storm water discharges and automobile oil. The removal of hydrocarbons from wastewater before discharge into receiving water bodies from wastewater effluents entails a variety of processes, with the most common processes being phytoremediation, bioremediation and chemical remediation. Phytoremediation is a cost effective method of reducing risk to human and ecosystem health posed by contaminated water. It entails the use of plants for the removal of contaminants and could involve mechanisms such as phytodegradation, rhizodegradation, rhizofiltration, phyto extraction, phytovolatilization, hydraulic control and phytostabilization. On the other hand, bioremediation is the use of microorganisms to breakdown or degrade pollutants in a contaminated site. The technology is low cost and has a generally high public acceptance. It consists of biostimulation (addition of nutrients to indigenous microorganisms) and bioaugmentation (addition of hydrocarbon degrading microorganisms). In the case of chemical remediation, it involves the use of chemicals for the treatment of contaminated sites. Substances, such as dispersants and solidifiers are used in chemical remediation. This study was aimed at reviewing the sources, impacts and remediation processes for hydrocarbon polluted wastewater effluents. This review was able to describe the sources and impacts of hydrocarbon polluted wastewater effluents and the various methods of treatment

Assessment of bacterial and fungal spoilage of some Nigerian

fermented and unfermented food

Screening of traditionally used Tanzanian medicinal plants for antifungal activity

Kisangau DP, Hosea KM, Lyaruu HVM, et al. Screening of traditionally used Tanzanian medicinal plants for antifungal activity. PHARMACEUTICAL BIOLOGY. 2009;47(8):708-716.Fungal infections represent a significant cause of morbidity and mortality especially in immunocompromised patients in the world today. Dichloromethane (DM) and aqueous (W) extracts of nine plants used traditionally for the treatment of fungal infections in Bukoba rural district in Tanzania were screened for antifungal activity against Candida albicans, Cryptococcus neoformans, and Aspergillus niger using agar well and disk diffusion methods. Dichloromethane extracts of Capparis erythrocorpos [CE] Isert (Capparaceae), Cussonia arborea [CA] Hochst. Ex A. Rich (Araliaceae), Drocaena steudneri [DS] Engl. (Dracaenaceae), Lannea schimperi [LS] (A. Rich) Engl. (Anacardiaceae), Rouvolfia vomitoria [RV] Afz (Apocynaceae), and Sapium ellipticum [SE] (Krauss) Pax (Euphorbiaceae) showed activity against all three fungi. Extracts of Rumex usambarensis [RU] (Dammer) Dammer (Polygonaceae) and Zehneria scabro [ZS] (L.f.) Sond. (Cucurbitaceae) had an activity limited to only one or two of the test organisms. Rhoicissus tridentata [RT] (L.Q Wild & Drum (Vitaceae) was the only plant without activity. Fractions of the active extracts CE, CA, DS, LS, and SE exhibited higher antifungal activity against one or more of the three fungi. Four compounds isolated from S. ellipticum also exhibited antifungal activity against one or more of the three fungi. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs), determined using the microplate assay method, ranged between 0.4 and 50.0 mu g/mL for crude extracts, 1.6 and 50.0 mu g/mL for semi-purified fractions, and 0.12 and 1.0 mu g/mL for pure compounds, as compared to 0.016-1.5 mu g/mL for fluconazole. We confirm the potential of traditionally used plants as a source of new drugs for treatment of fungal infections