Rhizoclonium grande Bioethanol in Biofuel Production by Transesterification of Jatropha curcas Oil

Abstract

There is a need for an alternative sustainable fuel based on renewable sources and efficient carbon dioxide scrubbers. Alkyl esters prepared by transesterification of vegetable oils from various plants have been evaluated. In this work the potential of sustainable macroalgae bioethanol in biofuel production by transesterification of Jatropha curcas oil was assessed. Rhizoclonium grande macroalgae was collected from Shimoni shores in Kwale, Shelly beach in Mombasa, Jamvi la Wageni in Mtongwe Likoni, English point near Kenya Marine and Fisheries Research Institute (KMFRI) Mombasa, dried and processed to obtain 5.36% ± 0.355% v/w bioethanol using Aspergilus niger for hydrolysis and Saccharomyces cerevisiae for fermentation. J. curcas seeds were collected from contracted farmers of Energy Africa in Shimba hills, Coast region. Oil from the seeds was machine cold pressed and solvent extracted using n-hexane giving 44% -53%v/w yield. The physicochemical properties of the J. curcas oil were investigated. Transesterification of J. curcas oil was carried out using bioethanol from the algae with 63% -70% FAEE yield. Characterisation of the bioethanol and ethyl esters was done using GC-MS. Physicochemical and fuel properties of the biofuel were investigated at Technical University of Mombasa (TUM), Jomo Kenyatta University of Agriculture and Technology (JKUAT), Government Chemist and Kenya Pipeline Laboratories in Mombasa. There was significant difference in physicochemical and fuel properties observed in density, calorific value, kinematic viscosity, pour point and cloud point between the Jatropha oil and Jatropha fatty acid ethyl esters (JAT FAEE) samples. No significant difference observed in the physicochemical and fuel properties between the JAT FAEE and standard biodiesel samples. This was according to statistical analysis of data done

Effect of Rhizoclonium grande Saturated Fatty Acid Ethyl Esters on Physicochemical and Fuel Properties of Jatropha curcas Biofuel

“…Jatropha ethyl esters from all the sample sites had physicochemical and fuel properties [17] acceptable by ASTM D 6751 (Table 4 ). The mean values obtained are comparable with those obtained for Jatropha curcas methyl esters from various publications [15,29] and were comparable to the ASTM standard biodiesel B100 [30] (Table 4) showing that they were within the specifications.…”

“…J. curcas oil (JO) was extracted using fabricated cold oil press and n-hexane as the solvent and also industrial blender for grinding [17]. The oil was allowed to settle then filtered using vacuum filtration.…”

“…Dry ethanol prepared from Rhizoclonium grande L. biomass was used for transesterification [17,23]. Dry potassium hydroxide was reacted with the bioethanol to produce the ethoxide ions mixture in a ratio of 1: 10.…”

“…The percentage yield of the ethyl esters from five different fields was found to be 59.0 ± 2.16% [17]. The relatively lower yield values of alkyl esters compared to methyl esters [27] could be attributed to incomplete separation and isolation of ethyl esters, glycerol and soap, though it may be more desirable to make ethyl esters because ethanol can be derived from renewable sources [17,25].…”

“…The final step involves deprotonating the catalyst, thus regenerating the active species, which is now able to react with a second molecule of the alcohol, starting another catalytic cycle [16]. Transesterification of triglycerides using ethanol from Rhizoclonium grande can be used which is more sustainable and cheaper than synthetic methanol [17]. Diglycerides and monoglycerides are converted by the same mechanism to a mixture of alkyl esters and glycerol.…”