A medium was developed to obtain the maximum yield of raw starch-digesting amylase from Aspergillus carbonarius (Bainier) Thom IMI 366159 in submerged culture with raw starch as the sole carbon source. The amylase was puri®ed to apparent homogeneity by sucrose concentration and ion exchange chromatography on S-and Q-Sepharose (fast¯ow) columns. SDS-PAGE revealed two migrating protein bands corresponding to relative molecular masses of 31.6 and 32 KDa. The enzyme was optimally active at pH 6.0±7.0 and 40°C, was unin¯uenced across a relatively broad pH range of 3.0±9.0 and retained over 85% activity between 30 and 80°C after 20 min incubation. ), forming predominantly maltose and relatively smaller amounts of glucose.

Biosurfactant-producing Serratia marcescens NSK-1 strain was isolated from soil contaminated with petroleum products. The organism, when grown in mineral salts medium with sucrose as sole carbon source, produced a surface-active anthrone-positive glycolipid. The biosurfactant was partially purified by liquid-liquid partition chromatography in chloroform-methanol mixture (1:1) and silica gel chromatography. It reduced the surface tension of distilled water from 72 dynes/cm to 40 dynes/cm and exhibited good emulsification activity with some vegetable oils and hydrocarbons. The biosurfactant exhibited stable surface activity over a wide range of temperature (30-100°C), pH (2-12) and salt concentration. There was no significant toxic effect shown by the biosurfactant towards mice when tested using the World Health Organization guidelines.

The antimicrobial activity of aqueous and ethanolic extracts of leaves of Piper guineense was determined on some bacteria and fungi, namely, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Saccharomyces cerevisiae, using agar well diffusion method and minimum inhibitory concentration (MIC). The ethanolic extract was found to show more activity than the aqueous extract on all the isolates. The diameter of zones of inhibition for the ethanolic extract ranged between 2 and 12 mm, while that of aqueous extract ranged between 5 and 8 mm. The MIC of the ethanolic extract was from 2.5 to 10 mg/ml, while for aqueous extract, the MIC was 10 to 20 mg/ml. Escherichia coli was found to show the greatest sensitivity, while P. aeruginosa showed the least sensitivity of all the isolates. The phytochemical analysis carried out on P. guineense leaves revealed the presence of alkaloids, tannins, saponins, glycosides and flavonoids. The presence of these phytochemicals supports the use of this plant as antimicrobial agent. P. guineense can therefore be used as antimicrobial agent.

Background: Poultry droppings from poultry farms and rice husks obtained from rice milling process are generally considered as wastes and discarded in Nigeria. Although many studies have shown that microbial fuel cells (MFCs) can generate electricity from organic wastes, little or no study have examined MFCs for generating electricity from poultry droppings and rice husk as electrode material. Findings: Laboratory-scale double-chamber MFCs were inoculated with concentrations of poultry droppings wastewater and supplied with rice husk charcoal as anode and cathode electrodes for electricity generation. Power outputs and dissolved organic carbon (DOC) removal efficiencies were compared between MFCs using rice husk charcoal (RHCE) as electrode and those using carbon cloth (CCE) as electrodes. The RHCE-MFC 2 containing 477 mg L −1 dissolved organic carbon produced a volumetric power density of 6.9 ± 3.1 W m −3 which was higher than the control and the CCE-MFCs by a factor of 2 and achieved at DOC removal efficiencies of 40 ± 1.2%. Conclusions: The results suggest that poultry droppings wastewater is a feasible feedstock for generating electricity in MFCs. The findings also suggest that rice husk charcoal is a potentially useful electrode material in MFCs.

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