ABSTRACT T T T The modelling of he modelling of he modelling of he modelling of batch batch batch batch production production production production of of of of citric acid from corn starch hydrolysate using Aspergillus niger ATCC 9142 citric acid from corn starch hydrolysate using Aspergillus niger ATCC 9142 citric acid from corn starch hydrolysate using Aspergillus niger ATCC 9142 citric acid from corn starch hydrolysate using Aspergillus niger ATCC 9142 was carried out was carried out was carried out was carried out in this work in this work in this work in this work. The annual production rate of citric acid stands at about 1.4 to 1.5 million tons and its demand estimated to be growing at a rate of about 3.5 to 4.0% annually [3]. Satisfying this demand through chemical or synthetic production of citric acid has been demonstrated to be unsustainable [4, large proportion of the world's demand for citric acid is satisfied through biotechnological means submerged fermentation of sugar containing substrates appears to be the most economical way of producing citric acid by Aspergillus niger In trying to study and understand the dynamic behaviour of a process, it is important to formulate dynamic models of such processes. These models upon calibration and validation will provide insights Results of simulating respectively. Results of simulating respectively. Results of simulating respectively. Results of simulating the production of citric acid wa the production of citric acid wa the production of citric acid wa the production of citric acid was a growth associated process. Optimum pH, initial sugar s a growth associated process. Optimum pH, initial sugar s a growth associated process. Optimum pH, initial sugar s a growth associated process. Optimum pH, initial sugar concentration and temperature for citric acid production concentration and temperature for citric acid production concentration and temperature for citric acid production concentration and temperature for citric acid production o o o obtained btained btained btained we we we were re re re5. is present in essentially all plants and in . It is a constituent of and it is abundant in most citrus fruits such as oranges, tangerines, lemon, berries, lime a metabolic product formed in the citric citric acid stands at and its demand is estimated to be growing at a rate of about 3.5 to 4.0% Satisfying this demand through chemical or synthetic production of citric acid has been ble [4,5]. Hence, a large proportion of the world's demand for citric acid through biotechnological means. Presently, submerged fermentation of sugar containing substrates appears to be the most economical way of rgillus niger [6,7].In trying to study and understand the dynamic behaviour of a process, it is important to formulate dynamic models of such processes. These models upon calibration and validation will provide insights as to how the process functions, changes in operating procedure and how amenable it is to control [8,9].The usefulness of a dynamic mathe...

This work presents the results of the determination of concentrations of the trace metals Ni, Zn, Mn, Pb, Cd, Cr, Co, Cu, and Fe in eggs from farms in Southern Nigeria. The mean concentrations (mg g À1 fresh weight) ranged from 0.6 to 1.2 for Ni, 3.1 to 8.9 for Zn, 0.45 to 0.65 for Mn, 0.4 to 1.2 for Pb, <0.09 to 0.3 for Cr, 0.1 to 0.3 for Cd, 0.26 to 0.34 for Co, 0.9 to 1.2 for Cu and 19.5 to 24.0 for Fe. The concentrations and estimated dietary intakes of these metals were below the respective statutory limits. The Target Hazard Quotient (THQ) values for the individual metals in all zones are less than 1, i.e., within safe levels. The combined THQ values for the different zones were greater than 1but less than 2, with a significant contribution of cobalt.

Additives such as low molecular weight alcohols, trace metals, phytate, lipids etc have been reported to stimulate Additives such as low molecular weight alcohols, trace metals, phytate, lipids etc have been reported to stimulate Additives such as low molecular weight alcohols, trace metals, phytate, lipids etc have been reported to stimulate Additives such as low molecular weight alcohols, trace metals, phytate, lipids etc have been reported to stimulate

This study investigated the heavy metal content and microbial composition of rhizosphere of Panicum maximum obtained from some auto mechanic workshops in Benin City, Nigeria. The grass was uprooted and soil sample was taken from its rhizosphere. The sample were labeled appropriately and immediately transported into a polythene bag covered with aluminium foil papers. It was then taken to the laboratory for heavy metals and microbial assay. The results showed that average plant density of Panicum maximum per 100m 2 of sampled subplots in the mechanic workshops was 8.50 in Ikpoba-Okha and 9