Natural honey is one of the most widely sought products due to its unique properties, which are attributed to the influence of the different groups of substances it contains. Honey is used for nutritional, medicinal and industrial purposes and it is an important commodity in the international market; serving as foreign exchange earner for many countries. In Nigeria, honey production (beekeeping) has the potential to develop as a prime agro-horticultural and forest-based industry which can be a major foreign exchange earner if international standards are met. The precise chemical composition and physical properties of natural honeys differ according to the plant species on which the bees forage. Differences in climatic conditions and vegetations are also important factors that can affect the various properties of honey. North-eastern Nigeria consists of humid, semi arid and arid climates with varying agricultural activities and blossoms from different types of vegetations, which can influence the natural composition and properties of honey. Thus, analysis of the biochemical composition of 18 honey samples obtained from different locations in the northeast sub-region of Nigeria was carried out to ascertain their qualities. Moisture and ash contents of the samples had average values of 16.00 ± 2.19 g/100 g and 0.47 ± 0.09 g/100 g, respectively. The protein contents ranged between 0.35 and 1.08g/100 g with a mean of 0.67 ± 0.25 g/100 g while fat content lied between 0.10 and 0.50 g/100 g with a mean of 0.29 ± 0.11 g/100 g. Total carbohydrate contents and Energy values showed average values of 82.30 ± 2.03 g/100 g and 1,401.33 ± 33.71 KJ/100 g, respectively. Fructose contents gave an average of 38.94 ± 0.90 g/100 g, while glucose contents had a mean value of 31.65 ± 2.79 g/100 g. The sucrose contents of the honey samples had a mean value of 1.84 ± 0.79 g/100 g. Total polyphenol and vitamin C contents showed mean values of 65.31 ± 19.50 mg Gallic Acid Equivalent (GAE)/100 g and 21.15 ± 3.99 mg/100 g, respectively. The results of this study indicate that the samples compare favorably with samples in many parts of the world and also fall within the limits of international standards.

The uptake and reduction of Cr(VI) by Aspergillus niger and A. parasiticus was studied in this journal. After 96 hours of growth, the culture solutions spiked with an initial dichromate concentration of 20 mg/l, were completely decolorized and had residual Cr(VI) concentrations of only 0.74 ± 0.55 and 1.69 ± 0.29 mg/l in A. niger and A. parasiticus cultures representing Cr(VI) removal of 96.3% and 91.6%, respectively. In the A. niger culture, significantly (P < 0.01) lower Cr(VI) concentrations were observed within 72 hours of growth compared to those of A. parasiticus, but in both cultures complete removal was almost achieved by 144 hours of growth. The rate of Cr(VI) removal was 0.21 ± 0.09 mgl -1 hr -1 and 0.20 ± 0.07 mgl -1 hr -1 for A. niger and A. parasiticus, respectively. Cellular concentrations of Cr(VI) in the two fungi increased significantly (P < 0.05 -0.001) with increasing concentrations of the dichromate treatments. Although tannic acid as sole source of carbon and energy gave significantly lower Cr(VI) removal than glucose (P < 0.001) and acetate (P < 0.01), it supported the removal of about 85.0% and 68.8% of the metal ion by A. niger and A. parasiticus, respectively. The active mycelia of both fungi showed significantly (P < 0.001) higher Cr(VI) removal than inactivated mycelia after incubation at 30°C for 72 hours. Incubation of cell -free extracts of both fungi with NADH at 30°C for 2 hours showed Cr(VI) reduction of 68.0% and 55.5% for A. niger and A. parasiticus, respectively. These findings suggest that uptake and metabolic reduction may be the process by which the two fungi are able to tolerate the toxic effects of hexavalent chromium. However, Cr removal via uptake by the two fungal biomass was observed to be in the range of 0.5 -1.78% only, for all the concentrations applied, which is insignificant when compared with the initial Cr concentration in the culture medium. The results obtained through this investigation indicate the possibility of treating waste effluents containing hexavalent chromium using Aspergillus niger and A. parasiticus.

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