James Ogbonna | University of Nigeria, Nsukka (original) (raw)

Papers by James Ogbonna

Cassava starch Garri Fufu Cassava flour Cassava starch Family/cottage processors Wastes are scatt... more Cassava starch Garri Fufu Cassava flour Cassava starch Family/cottage processors Wastes are scattered and used for animal feed Many cassava flour and cassava starch companies. Many with capacity of more than 5 t/day and generate average of 495kg wastes per tonne These wastes can be economically converted to bio-ethanol Cassava Processing Wastes Peels 250-300 kg/t Dust 30 kg/t Fibers 20~40 kg Cassava flour Cassava starch Peels 250~300 kg/t Pulp 400 kg/t

Vegetos, Jun 17, 2021

Bioconversion of food crops to bioethanol has generated numerous issues, necessitating the need f... more Bioconversion of food crops to bioethanol has generated numerous issues, necessitating the need for alternative feedstock. Pawpaw seeds (PS) were pretreated by different methods, dried and ground into flour. The flours were saccharified using crude amylase from Aspergillus niger and the reducing sugar produced was evaluated. Optimum conditions for ethanol production from the pawpaw seeds were determined. Seeds pretreated with sulphuric acid produced the highest amount of sugar (8.07 g/10 g PS), followed by seeds boiled in water (7.31 g/10 g PS). PS pretreated with sodium hydroxide produced 4.83 g/10 g PS. The optimum pH and temperature for amylase activity were 4.0 and 50 °C respectively, while the optimum substrate concentration for hydrolysis was 8 g/10 g PS flour. Increase in glucose concentration from 0.1 to 0.3 (g/100 ml) resulted in increase in the fermentable sugar production from 6.56 to 9.64 g/10g PS. The percentage yeast extract and peptone which gave the maximal fermentable sugar production from PS were 0.1% and 0.4%, respectively. The maximum ethanol concentration (4.33% v/v) produced by simultaneous saccharification and fermentation of pawpaw seed was obtained after 12 h of fermentation. These results indicate that pawpaw seeds, a food waste can be converted into ethanol within 12 h of fermentations through simultaneous saccharification and fermentation.

Biotechnology Advances, Mar 1, 2023

日本生物工学会大会講演要旨集, Aug 25, 2013

Energy and Power Engineering, 2018

A total of 500 thermotolerant fermenting yeast isolates (100 from palm-wine and 400 from spoilt f... more A total of 500 thermotolerant fermenting yeast isolates (100 from palm-wine and 400 from spoilt fruits) were screened for ethanol production at high temperatures. The best isolate that produced up to 4% ethanol from 10% glucose at 45˚C was selected for further experiments. The optimum pH for ethanol production by the isolate was pH 6 at both 30˚C and 42˚C. The isolate was identified as Pichia kudriavzevii base on the 18s ribosomal DNA. Ethanol production from 200 g/L cassava pulp using Simultaneous Saccharification and Fermentation (SSF) method at 30˚C and 42˚C by the isolate was investigated. At 30˚C, an ethanol concentration of 30 g/L was produced. This represents an ethanol yield of 0.15 g/g of cassava pulp and 58.8% of the theoretical yield. However at 42˚C, the concentration of ethanol produced increased to 42 g/L representing an ethanol yield of 0.21 g/g of cassava pulp and 82.4% of the theoretical yield. The isolate produced slightly higher ethanol than the two typed strains NCYC 587 and NCYC 2791 at 42˚C. This isolate has a good potential to be used for commercial bioethanol production since it can produce ethanol at 45˚C without a significant drop in ethanol yield.

Photosynthetic microorganisms can be engineered to produce pharmaceuticals, chemical intermediate... more Photosynthetic microorganisms can be engineered to produce pharmaceuticals, chemical intermediates, and clean energy (e.g., hydrogen). They also fix atmospheric carbon dioxide--an important consideration as increased levels of carbon dioxide are linked to global warming. As a first step in the photobioreactor design, the authors investigated the relative significance of the exponential and the linear growth rates during light-limited batch cultivation of photosynthetic cells using various types and sizes of photobioreactors. They also developed a mathematical model that could explain the existence of the various growth phases during the light-limited batch cultivation. Because the cost of electricity is high, use of solar energy is obviously desirable, because it is abundant and free. However, an appropriate method for harvesting the solar energy and distributing the light inside the photobioreactor is required. A light collection device consisting of Fresnel lenses is used to collect the solar light, which is then distributed inside the reactor through the optical fibers. Because the position of the sun changes continuously, the device is equipped with a light-tracking sensor so that the lenses rotate with the position of the sun. Because of diurnal and seasonal changes in the sunlight intensity, however, high volumetric productivity is difficult to achieve if only solar energy is used for reactor illumination. For maximum productivity, therefore, the solar light should be supplemented with an artificial light source at night and on cloudy days.

Biofuels, Jan 30, 2019

Three thermotolerant yeasts capable of producing more than 7 g/L of ethanol from 30 g/L xylose we... more Three thermotolerant yeasts capable of producing more than 7 g/L of ethanol from 30 g/L xylose were isolated. Molecular identification using ribosomal DNA internal transcribed spacer showed that isolates Pa27 and Pi131 were strains of Pichia kudriavzevii while Ma9 was a strain of Candida tropicalis. Under optimal conditions, Pa27, Ma9 and Pi131 produced maximum ethanol yields (g ethanol/g xylose) of 0.35 ± 0.002, 0.35 ± 0.007 and 0.39 ± 0.002, respectively. At a fermentation temperature of 42 C, the maximum ethanol yields (g ethanol/g xylose) were 0.21 ± 0.005, 0.22 ± 0.005 and 0.23 ± 0.006 after 96 hours for Pa27, Ma9 and Pi131, respectively. The isolates co-fermented glucose and xylose to ethanol, and the presence of a small amount of glucose improved the xylose utilization rate. Pa27 was the best strain for fermentation of a mixture of xylose and glucose. At the optimum ratio of glucose to xylose (4:6 to 5:5), ethanol yield by Pa27 decreased from 0.43 to 0.35 when the temperature was increased from 30 to 42 C. It is notable that even at 42 C, all the three isolates fermented a mixture of xylose and glucose with ethanol yields higher than 0.33 g ethanol/g sugar.

日本醗酵工学会大会講演要旨集, Nov 2, 1987

Journal of Sustainable Bioenergy Systems, 2018

Microalgae with high oil productivities are most desired in biodiesel production. Chlorella lewin... more Microalgae with high oil productivities are most desired in biodiesel production. Chlorella lewinii SUB3545914, was isolated and assessed for its growth rates, lipid productivities and fatty acid profiles under heterotrophic cultivation. The alga was isolated after enrichment in BG-11 medium (pH = 7.3) under a light intensity of approximately 17.5 µE•m −2 •s −1 at 30˚C ± 2˚C. In addition to morphology, polymerase chain reaction (PCR) and metagenomics were used for isolate identification. The DNA was sequenced and multiple sequence alignment of the BLASTED results revealed 95% similarity to Chlorella lewinii. Maximum growth (3.15 ± 0.06 g•L −1), lipid content (44.0%) and lipid volumetric productivities (118.80 ± 3.02 mg•L −1 •day −1) in glucose supplemented media were more appreciable in comparison with the glycerol counterparts. Similarly, the highest growth (2.03 ± 0.68 g•L −1), lipid content (31.47%) and lipid productivities (47.21 ± 2.08 mg•L −1 •day −1) in glycerol supplemented media were more than those got under autotrophic cultivation. Chlorophyll contents did not vary remarkably in heterotrophic cultures. The major fatty acids obtained by Gas Chromatography Mass Spectrometry (GC-MS) were oleic and Octadecanoic acids for all the culture conditions. Chlorella lewinii is appropriate for accumulating lipids for biodiesel under heterotrophic cultivation on glucose because of high lipid volumetric productivities.

Journal of Advances in Biology & Biotechnology

Polycyclic aromatic hydrocarbons are chemical substances that are produced from natural sources s... more Polycyclic aromatic hydrocarbons are chemical substances that are produced from natural sources such as volcanic eruptions and from anthropogenic sources such as incomplete combustion of fuels such as coal, oil, gas and waste materials. They are mostly implicated among numerous toxic compounds in the ecological system. Exposure of such organic pollutants in an environment can endanger animals, plants, microbial, soil, and aquatic lives. Human beings are at a high risk of developing cancers due to pollutants exposure. The existence of such pollutants in the surroundings can endanger microbial life by affecting cell growth, shape and metabolic process, alters genetic composition and membranes of microbial cells. The major routes of microbial degradation of organic pollutants are via growth and co-metabolism. The processes enable microorganisms to metabolize toxic compounds in the cells milieu, so as to transform contaminants into harmless forms such as carbon dioxide and water. Biorem...

Bio-Research

The crude oil degradation potential of bacterial isolates from three contaminated sites in Nigeri... more The crude oil degradation potential of bacterial isolates from three contaminated sites in Nigeria were investigated. Seven bacterial isolates namely Pseudomonas aeruginosa strain W15, Pseudomonas aeruginosa strain N3R, Serratia marcescens strain N4, Providencia vermicola strain W8, Serratia marcescens strain W13, Pseudomonas aeruginosa strain W11 and Pseudomonas protegens strain P7 were isolated and identified using molecular methods. Isolates N4, N3 and W13 showed higher % total petroleum hydrocarbon (TPH) degradation of 79.26%, 78.96% and 78.69% respectively than W15, P7, W8 and W11 with % TPH degradation of 68.96%, 62.14%, 59.75% and 59.00% respectively. W13 showed the fastest degradation rate with 78.72% within the first 14 days of incubation; however, after the 14th day, there was no progressive change in % TPH. W11 showed degradation of wider range of hydrocarbon components originally in the crude oil as well as the complete degradation of most intermediates formed. The isola...

Biosafety and Bioethics in Biotechnology, 2022

Asian Journal of Biotechnology and Bioresource Technology, 2022

Aims: To isolate fungi capable of simultaneous production of amylase and cellulase Study Design: ... more Aims: To isolate fungi capable of simultaneous production of amylase and cellulase Study Design: The experiment was carried out in aseptic conditions, data were subjected to one way Analysis of Variance (ANOVA) and the means were separated using Least Significance Deference (LSD). Place and Duration of Study: Department of Microbiology, University of Nigeria, Nsukka, Enugu State, Nigeria, between August 2010 and July 2013. Methodology: Plantain peels and infected bark of the stump of a tree were collected for fungi isolation. A 1 g sample each was weighed separately and added to 10 ml distilled water, 1 ml of each of the diluents was plated out on Emerson’s yeast phosphate soluble starch (YPSs) medium. After growth, colonies were picked and subcultured several times for purity. The isolates were characterized and identified based on colony morphology and microscopic examination. They were later screened for amylase and cellulase activities by growing them on various concentrations ...

Biotechnology and Applied Biochemistry, 2021

Effects of carbon source, nitrogen source, and alternatingly submerging the cells and exposing to... more Effects of carbon source, nitrogen source, and alternatingly submerging the cells and exposing to gaseous oxygen on pigment production by Talaromyces purpurogenus LC128689, as well as pH, temperature, and UV stability of the pigments were investigated. Although fructose supported higher cell growth, a mixture of glucose and glycerol resulted in higher pigment production. Out of the organic and inorganic nitrogen sources investigated, peptone gave the highest cell concentration (7.2 ± 1.1 g/L) and pigment production (p ≤ 0 .05). The cells were then immobilized in loofa sponge and cultivated under alternating liquid phase–air phase (ALAP) system whereby the cells were alternatingly submerged and exposed to gaseous oxygen. After 20 days of cultivation, the concentrations of the red, orange, and yellow pigments were 30.15 AU500 nm, 15 AU460 nm, and 6.25 AU400 nm, respectively. In comparison with submerged culture in flasks, the red and orange pigments were 100% and 50% higher (p ≤ 0.05)...