Eriola Betiku

METHANOLYSIS OPTIMIZATION OF SESAME (SESAMUM INDICUM) OIL TO BIODIESEL AND FUEL QUALITY CHARACTERIZATION

Statistical approach was employed to optimize biodiesel production from sesame oil in this work. Precisely, response surface methodology was applied, and the effects of four variables, viz. reaction temperature, catalyst amount, reaction time, and methanol/oil molar ratio, and their reciprocal interactions were determined. Central composite rotatable design was used to generate a total of 30 individual experiments, which were designed to study the effects of these variables during alkali-catalyzed methanolysis of sesame oil. A statistical model predicted the highest conversion yield of sesame biodiesel to be 99.71% at the following optimized variable conditions: reaction temperature of 63°C, catalyst amount of 1.04 wt.%, and methanol/oil molar ratio of 6.24, with a reaction time of 51.09 min. Using these variables under experimental condition in four independent replicates, an actual biodiesel yield of 98.36% was accomplished. The fuel properties of biodiesel produced were found to be within the ASTM D6751 and DIN EN 14214 biodiesel specifications.

A home made kit for plasmid DNA mini-preparation

Many methods have been used to isolate plasmid DNA, but some of them are time consuming especially when extracting a large number of samples. Here, we developed a rapid protocol for plasmid DNA extraction based on the alkaline lysis method of plasmid preparation (extraction at pH 8.0). Using this new method, a good plasmid preparation can be made in approximately one hour. The plasmids are suitable for any subsequent molecular applications in the laboratory. By applying the recommendations to avoid contaminations and to maximize the plasmid yield and quality during extraction, this protocol could be a valuable reference especially when analyzing a large number of samples. (African Journal of Biotechnology: 2003 2(4): 87)

A comparative study of the hydrolysis of gamma irradiated lignocelluloses

The effect of high-dose irradiation as a pretreatment method on two common lignocellulosic materials; hardwood (Khaya senegalensis) and softwood (Triplochiton scleroxylon) were investigated by assessing the potential of cellulase enzyme derived from Aspergillus flavus Linn isolate NSPR 101 to hydrolyse the materials. The irradiation strongly affected the materials, causing the enzymatic hydrolysis to increase by more than 3 fold. Maximum digestibility occurred in softwood at 40kGy dosage of irradiation, while in hardwood it was at 90kGy dosage. The results also showed that, at the same dosage levels (p < 0.05), hardwood was hydrolysed significantly better compared to the softwood.

Sorrel ( Hibiscus sabdariffa ) Seed Oil Extraction Optimization and Quality Characterization

Aims: This study was aimed at separating seed oil from sorrel (Hibiscus sabdariffa ) oilseeds using application of solvent extraction method. The process was optimized using response surface methodology and the quality of the seed oil was determined. Methodology: Optimization of oil extraction from the oilseeds using response surface methodology was carried out. The effects of three independent factors (extraction time, solvent volume and sample weight) and their respective interactions on the response, oil yield, were investigated. A total of 17 experimental runs were generated using BoxBehnken design. The extracted seed oil was characterized to determine its quality. Results: A quadratic polynomial was obtained to predict the oil yield and the ANOVA test showed the developed model to be significant ( P < 0.05). A statistical model predicted the maximum seed oil yield to be 18.25% at the optimal condition of sample weight, 22g, solvent volume, 157 ml and time, 2 h. The optimized condition was validated with the actual oil yield of 17.85%, which was well within the range predicted. The seed oil analysis showed the physical state of the oil to be liquid/yellow-greenish in colour, specific gravity 0.886 ± 0.026, viscosity (at 40oC) 15.40 cP, p-anisidine value 6.31, Totox number 16.31, %FFA 0.40 ± 0.01, acid value 0.80 ± 0.01 mg KOH.g oil

Auto-hydrolysis of lignocellulosics under extremely low sulphuric acid and high temperature conditions in batch reactor

Batch reactors were employed to investigate the kinetics of cellulose hydrolysis under extremely low acid (ELA) and high temperature condition. The sawdust was pretreated by Autohydrolysis prior to the batch reaction. The maximum yield of glucose obtained from the batch reactor experiment was about 70% for the pretreated sawdust, this occurred at 210 and 220°C. The maximum glucose yield from the untreated sawdust was much lower at these temperatures, about 55%. The maximum yields of glucose from the lignocellulosics were obtained between 15th and 20th minutes after which gradual decrease was observed.

Fermentation parameter optimization of microbial oxalic acid production from cashew apple juice

The potential of cashew apple juice (CAJ) as a carbon source for oxalic acid (OA) production via fermentation process was investigated in this study. The effects and interactions of CAJ concentration, time, pH, NaNO3 concentration and methanol concentration on OA production were determined in a central composite design (CCD) and the process was modelled and optimized using response surface methodology (RSM). The results showed that OA fermentation can be described significantly (p < 0.05) by a quadratic model giving regression coefficient (R2) of 0.9964. NaNO3 concentration was the most significant positive variable while methanol was not a significant variable. A maximum OA concentration of 122.68 g/l could be obtained using the optimum levels of CAJ of 150.0 g/l, pH of 5.4, time of 7.31 days, NaNO3 of 2 g/l and methanol of 1% volume. The production of OA was found to increase from 106.75 to 122.68 g/l using the statistically design optimization. This study revealed that CAJ could serve as an inexpensive and abundant feedstock for fermentative OA production, the resulting model could be used in the design of a typical pilot plant for a scale up production.

Media Evaluation of Bioethanol Production from Cassava Starch Hydrolysate Using Saccharomyces cerevisiae

Nine different media containing three different nitrogen sources, concentration of carbon source (cassava starch hydrolysate), and the pH were run in shake flasks to produce bioethanol using Saccharomyces cerevisiae. Analysis of variance of the results from the shake flask showed that there was no significant difference (P > 0.05) in the maximum concentration of ethanol (Pt) produced from the media. From the bioreactor studies, similar kinetic parameters, including Pt of 48.16 g/L with theoretical yield (Yetoh) of 92% and Pt of 47.13 g/L with Yetoh of 92%, were recorded from 100 g/L carbon source in the complex and minimal media, respectively.

Enzymatic hydrolysis optimization of sweet potato (Ipomoea batatas) peel using a statistical approach

In this work, two-step enzymatic hydrolysis of sweet potato peel was optimized. The effects of time, enzyme dose and temperature on glucose concentration were investigated. The Box-Behnken design was applied and a total of 17 experimental runs were generated for each step. For the liquefaction step, an ANOVA test showed the quadratic model obtained to be significant (p < 0.05). The statistical model predicted the maximum glucose concentration to be 126.66 g/L at a temperature of 56.4 oC, α-amylase dose 1% (v/v) and time 60 min. A quadratic model was also obtained for the saccharification step and the model was also significant (p < 0.05). The statistical model for the second step predicted the maximum glucose concentration to be 178.39 g/L, established at the temperature of 45 oC, glucoamylase dose 1% (v/v) and time 60 min. The optimized liquefaction and saccharification conditions were validated with the actual glucose concentrations of 126.03 and 176.89 g/L, respectively.

Comparison of Artificial Neural Network and Response Surface Methodology Performance on Fermentation Parameters Optimization of Bioconversion of Cashew Apple Juice to Gluconic Acid

Abstract The study examined the impact and interactions of cashew apple juice (CAJ) concentration, pH, NaNO3 concentration, inoculum size and time on gluconic acid (GA) production in a central composite design (CCD). The fermentation process and parameters involved were modeled and optimized using artificial neural network (ANN) and response surface methodology (RSM). The ANN model established the optimum levels as CAJ of 250 g/l, pH of 4.21, NaNO3 of 1.51 g/l, inoculum size of 2.87% volume and time of 24.41 h with an actual GA of 249.99 g/l. The optimum levels predicted by RSM model for the five independent variables were CAJ of 249 g/l, pH of 4.6, NaNO3 of 2.29 g/l, inoculum size of 3.95% volume, and time of 38.9 h with an actual GA of 246.34 g/l. The ANN model was superior to the RSM model in predicting GA production. The study demonstrated that CAJ could serve as the sole carbon source for GA production.

Optimization of Sweet Potato Starch Hydrolyzate Production and Its Potential Utilization as Substrate for Citric Acid Production

Aims: The aims of this work was optimization of two -step enzymatic hydrolysis of sweet potato starch using statistical approach and subsequent utilization of the hydrolyzate obtained for citric acid production. Methodology: Box Behnken design was used in this s tudy to generate a total of 17 individual experiments for each step of the hydrolysis (liquefaction and saccharification steps). These were designed to study the effect of temperature, time and pH on the sweet potato starch hydrolyzate (SPSH) concentration . The optimization was carried out using response surface methodology (RSM). The SPSH obtained was used to culture Aspergillus nigerfor citric acid production. Results:A statistically significant quadratic regression model (P<