Influence of nitrogen sources on ethanol production by Saccharomyces Spp in the presence of formic acid

Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars in the hydrolysates to bioethanol. The influence of different nitrogen sources supplemented media on bioethanol fermentation with Saccharomyces spp in the presence of formic acid was studied. The addition of ammonium sulphate and urea significantly increased cell number, glucose utilization, ethanol and glycerol production when compared with control media. It was observed that supplementation with nitrogen sources contributed assimilable nitrogen for the yeast strains growth when stressed with formic acid. The best concentration of nitrogen to be utilized by yeast was found to be 0.80 gN/L. The maximum cell numbers were 8.17± 0.23x 107 and 8.68± 0.16x 107 cells/mL for ammonium sulphate medium while control had the least of 4.00± 0.20x 107 and 4.97± 0.08x 107 cells/mL for S. cerevisiae NCYC2592 and S. arboricolus 2.3319 respectively. Ethanol accumulation increased with the consumption of glucose. The maximum ethanol production were 20.49 ± 1.24 and 19.74± 0.89 g/L using ammonium sulphate for S. cerevisiae NCYC2592 and S. arboricolus 2.3319 respectively. There was significant difference in ethanol production when the nitrogen sources were compared with the control medium (p< 0.05). The highest glycerol produced were 2.21 ± 0.04 and 3.11± 0.05 g/L using ammonium sulphate for S. cerevisiae NCYC2592 and S. arboricolus 2.3319 respectively. The conclusion was that yeast tolerance to formic acid and ethanol production could be achieved when fermentation medium is supplemented with nitrogen sources specifically ammonium sulphate.Keywords: Lignocellulose, inhibitors, Saccharomyces, fermentation, yeast, biofue

Relationship between soil contents and plasma levels of selenium, chromium and manganese in healthy adult Nigerians

The soil contents of trace elements selenium, chromium and manganese were measured to determine their impact on the plasma levels of 160 healthy adult Nigerians in five different experimental locations in Cross River and Akwa Ibom States, South - South Nigeria. The mean (±SD) soil selenium, chromium and manganese concentrations were 2.86 ± 3.97, 15.93 ± 3.35 and 90.33± 42.65 mg/kg, respectively. Manganese soil concentration was the highest and selenium soil concentration was the lowest in all the locations. The mean (±SD) plasma selenium, chromium and manganese concentrations were 0.006, 0.111 ± 0.031 and 0.028 ± 0.024 mg /1, respectively. There were no significant differences between the concentrations of the trace elements in the soil and the plasma levels as determined by t-test. Plasma levels of chromium and manganese according to the study were adequate but that of selenium was low.Keywords: Healthy adult Nigerians, trace elements, plasma level, soil contentAfrican Journal of Biotechnology Vol. 12(34), pp. 5339-534

Culture, tradition, and taboo: understanding the social shaping of fuel choices and cooking practices in Nigeria

Wood fuel remains the most widely used domestic fuel amongst resource poor groups in many low-income countries, despite the environmental and health problems associated with exposure to wood smoke. Studies on household air pollution concentrate predominately on socio-economic and behavioural factors and health with little emphasis on socio-cultural factors. The study contributes to the understanding of household air pollution (HAP) and wood fuel harvesting for domestic activities in low-income countries from a cultural perspective that draws on householders’ wood fuel selection and cooking practices in Ado Ekiti, Nigeria. In this paper, we explore how cultural norms influence households’ cooking practices, energy choices and perceptions of the causes of ill health and misfortune. The research draws on household surveys, participant observation and semi-structured interviews with householders of four different ethnic origins in nineteen villages. Key findings reveal low levels of awareness of HAP-related illness coupled with high levels of attachment to traditional biomass-fuelled cooking systems for a range of cultural and pragmatic reasons. It is argued that ‘ethnic-specific’ traditional norms and taboos provide a more important influence on fuel choice, wood fuel harvesting and cooking practices than the lived realities of exposure to household air pollution

Effect of Nutrient Runoff on the Water Microbiology and Quality of a Community Water Source: A Case Study of Orogodo River

The water microbiology and quality of Orogodo River were investigated at four stations during the wet and dry seasons. Results indicated decreased levels of BOD and COD and a reduced level of DO along the stations. The pH of the water was acidic ranging from 3.25 – 6.6. The TSS and TDS were high due to high siltation of the water. Low levels of zinc, lead, mercury and cadmium were recorded with high level of iron in stations 1, 2, 3 and in the tissues of the Tilapia fishes analyzed. The turbidity level decreased with increased temperature along the stations. Microbial analysis showed the presence of Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Stapylococcus aureus, Streptococcus faecalis, Shigella dysenteriae and Salmonella typhi. Streptococcus faecalis was the most prevalent organism isolated in both seasons. Keywords: Microbiology, Quality, Nutrient Runoff, Community Water Source, Orogodo River> Tropical Freshwater Biology Vol. 15 2006: pp. 71-8