Assessment of the Potentials of Production of Bioethanol Using Cyperus esculentusL. (Tigernut) Residue by Simultaneous Saccharification and Fermentation
Background: The substitution of the use of fossil fuels with fuels from renewable energy sources has been widely advocated. Bioethanol is one of the fuels used by automobiles in the transport sector as the sole fuel or blended with fossil fuels in different ratio.
The Aim of the Study: The aim was to assess the potentials of tiger nut residue as feedstock in bioethanol production.
Materials and Methods: Bioethanol was produced by fermentation, using three different slurry concentrations of the residue to water ratio of 1:15, 1:20 and 1:30, by the use of co-culture of Aspergillus niger and Saccharomyces cerevisiae and the co-culture of A. niger, Bacillus subtilis and S. cerevisiae. The concentration of the produced bioethanol was obtained using spectrophotometer using chromium VI reagents.
Results: In the first set-up (using A. niger and S. cerevisiae), the highest percentage mean concentration of 1.16% of the produced bioethanol was recorded in day 3 of the 1:30 (residue to water) slurry ratio and the lowest of 0.11% in day 1 of 1:15 slurry ratio. No significant difference (p<.05) was observed in the percentage mean concentrations produced across the three slurries in the all the days, and also across the days in the 1:20 and 1:30 slurry ratios. The pH also decreases as the time of the fermentation increases. In the second set-up, the highest percentage mean concentration of 0.33% was obtained on day 5 of 1:15 slurry and the lowest of 0.14% on day 1 of 1:20. A significant difference (p<.05) was observed across the slurries in day 4 and 5, but none was observed on day 1, 2 and 3.
Conclusion: The results obtained indicate that bioethanol can be produced using Tigernut residue by simultaneous saccharification and fermentation.
Copper nanoparticles were synthesized by the reduction method using copper (II) sulfate with the reducing agent (ascorbic) acid in aqueous mandarin (Citrus reticulata) peel extract characterisation, and protective polyvinyl alcohol (PVA, Mw = 85000 g/mol). The morphology and structure of the synthesized copper nanoparticles ranged from 10 – 40 nm by Dynamic Light Scattering (DLS), transmission Electronic Microscope (TEM) and Field Emission Scanning Electron Microscopy (FE – SEM). It can be controlled during synthesis by varying the reaction temperature, pH and relative ratio of copper sulfate to the surfactant. These synthesized copper nanoparticles were found to be effective in controlling the growth of pathogens viz. Corticiumsalmonicola and Phanerochaetesalmon color. The antifungal activities of copper nanoparticles were enhanced by increasing their concentration and copper nanoparticles recorded higher events than those of copper sulfate.
The study investigates microbial deteriogens of lubricating oils used on industrial generators. Total heterotrophic bacterial and total fungal counts were determined using the spread plate method. Bacterial isolates were screened for the utilization of lubricating oil and the rate of biodeterioration was determined by monitoring the optical density and pH of medium containing specific bacterial isolates from lubricating oil. Physico-chemical characteristics of lubricating oil were determined following standard procedures and petroleum hydrocarbon profile was determined using Gas Chromatography. Bacterial counts of used and unused samples ranged from 5.55 log cfu/ml to 7.83 log cfu/ml and from 4.64 log cfu/ml to 4.86 log cfu/ml respectively while fungal counts ranged from 6.60 log cfu/ml to 8.04 log cfu/ml and from 0 log cfu/ml to 7.32 log cfu/ml respectively. Bacterial isolates identified in the study include; Micrococcus sp, Citrobacter sp., Bacillus sp., Serratia sp., Corynebacterium sp., Staphylococcus sp., Shigella sp., while the fungal genera isolated include; Penicillium, Aspergillus, Fusarium, Cryptosporium, Candida and Saccharomyces species. Screen test for the utilization of used and unused oil samples by bacterial isolates showed that all isolates utilized the lubricating oil. Results further revealed that there was a consistent and significant (P < 0.05) increase in optical density and a fluctuation in pH during deterioration monitoring. Petroleum hydrocarbon profile analysis after 28 days of study revealed lower concentrations of hydrocarbon components in the used oil samples compared to the unused samples, this confirm the fact that isolated organisms may have utilized the lubricating oil as a source of carbon and energy thereby affecting its quality and performance.
Petroleum hydrocarbon oil contaminated soils were excavated from a gas station from Nicosia Cyprus, Turkey and subjected to fungal isolation/analysis. During the fungal essay, Aspergillus nigar, Penicellum notatum and Mucorales were isolated and identified. Aspergillus nigar was selected and cultivated for lipase enzyme production due to its role in lipase production. The produced lipase enzyme was immobilized and the number of lipases recovered after purification was 85.1%. The purified enzymes that were supported by physical adsorption which resulted in high (85%) yield showed high stability than free lipase, encouraged transesterification in this study. Pretreatment evaluation of groundnut powder showed high cellulose yield (82.3% and 87%) and high lignin removal of 75%, 88% respectively for lipase enzyme accessibility and ethanol production. Transesterification involving purified lipases and groundnut shell fermented ethanol yielded Methyl ester which represents the organic biodiesel with a C18 number showing a minimum level of lubricity for friction reduction between surfaces when a car is on motion and has specific gravity 0.95 ul, density 15.5°c, and calorific value of 43.2 MJ. Kg.
Lipases are the enzymes that cleave carboxylic ester bonds and are produced by many living organisms like bacteria, fungi, plants and animals. These are the family of hydrolases. Their action is to hydrolyze triglycerides into monoglycerides, diglycerides, glycerol and fatty acids. As the lipases can perform several reactions like esterification, interesterification and transesterification they are widely used in leather, textile, cosmetic, detergent, fine chemistry, cellulose, pulp, paper, medical, effluent treatment, biodiesel production, food and pharmaceutical industries. These enzymes are low cost and easy to produce because of several sources and new technological developments in purification methods. The present paper discusses the various lipase sources, isolation, characterization and purification methods along with their applications.