Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development

Most of the present studies on micro-algae development focused on enhanced biomass productivity with limited information on the effects of growth modes and nutrients availability on the expected biofuel critical performance properties as well as development of sustainable technologies for micro-alga...

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Main Authors: Folayan Adewale Johnson, Bilal Patel
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025019437
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author Folayan Adewale Johnson
Bilal Patel
author_facet Folayan Adewale Johnson
Bilal Patel
author_sort Folayan Adewale Johnson
collection DOAJ
description Most of the present studies on micro-algae development focused on enhanced biomass productivity with limited information on the effects of growth modes and nutrients availability on the expected biofuel critical performance properties as well as development of sustainable technologies for micro-algae energy production.In this study, the biofuel properties of mixotrophic chlorella vulgaris micro-algae biomass that was synthesized by a nickel-doped calcium oxide heterogeneous catalytic transesterification process were investigated under standard laboratory procedures. The Ni-CaO solid catalyst was prepared by co-precipitation of calcium oxide (CaO) with hydrated nickel nitrate dopant (Ni (NO3)2.6H20 (nickel (II) nitrate hexahydrate). Carbon IV Oxide solvent in its supercritical states (SCCO2) was used for triacylglycerols (TAGs) extraction. Advanced structural and analytical spectroscopic techniques including SEM and XRD, GC-MSD and FTIR were used for catalyst, extracted lipids and biodiesel characterizations respectively.A lipid content of 47.60 ± 2.31 % which consists majorly of long chain mono-unsaturated fatty acids with few poly-unsaturated molecules was obtained from the SFE process. Interestingly, the Ni-CaO catalyst has superior catalytic power with a glyceride conversion efficiency of 98.6 % due to replacement of ca2+ with nickel transition metal ions in the CaO lattice which enhances better catalytic performance by increased active surface area and improved catalytic activities. The biodiesel has lower density and kinematic viscosity values of 0.858 g/cm3 at 15 °C and 3.61mm2/s at 40 °C. This promotes efficient fuel-air mixture and better atomization and combustion characteristics. Finally, the ester biofuel has higher cetane index and heating values of 55.6 and of 41.12 MJ/Kg respectively due to higher proportion of long chain and MUFAs in its ester structure. This inevitably promotes better ignition quality, lower fuel consumption, enhances superior fuel combustion and performance characteristics and reduced particulate matter emissions.
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spelling doaj-art-d2fd0b6ddfd64b01b02bc6a1456450ec2025-08-20T02:20:54ZengElsevierResults in Engineering2590-12302025-09-012710587210.1016/j.rineng.2025.105872Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel developmentFolayan Adewale Johnson0Bilal Patel1Corresponding author.; Department of Chemical and Materials Engineering, College of Science and Engineering, University of South Africa, Florida Science Campus, Johannesburg, South AfricaDepartment of Chemical and Materials Engineering, College of Science and Engineering, University of South Africa, Florida Science Campus, Johannesburg, South AfricaMost of the present studies on micro-algae development focused on enhanced biomass productivity with limited information on the effects of growth modes and nutrients availability on the expected biofuel critical performance properties as well as development of sustainable technologies for micro-algae energy production.In this study, the biofuel properties of mixotrophic chlorella vulgaris micro-algae biomass that was synthesized by a nickel-doped calcium oxide heterogeneous catalytic transesterification process were investigated under standard laboratory procedures. The Ni-CaO solid catalyst was prepared by co-precipitation of calcium oxide (CaO) with hydrated nickel nitrate dopant (Ni (NO3)2.6H20 (nickel (II) nitrate hexahydrate). Carbon IV Oxide solvent in its supercritical states (SCCO2) was used for triacylglycerols (TAGs) extraction. Advanced structural and analytical spectroscopic techniques including SEM and XRD, GC-MSD and FTIR were used for catalyst, extracted lipids and biodiesel characterizations respectively.A lipid content of 47.60 ± 2.31 % which consists majorly of long chain mono-unsaturated fatty acids with few poly-unsaturated molecules was obtained from the SFE process. Interestingly, the Ni-CaO catalyst has superior catalytic power with a glyceride conversion efficiency of 98.6 % due to replacement of ca2+ with nickel transition metal ions in the CaO lattice which enhances better catalytic performance by increased active surface area and improved catalytic activities. The biodiesel has lower density and kinematic viscosity values of 0.858 g/cm3 at 15 °C and 3.61mm2/s at 40 °C. This promotes efficient fuel-air mixture and better atomization and combustion characteristics. Finally, the ester biofuel has higher cetane index and heating values of 55.6 and of 41.12 MJ/Kg respectively due to higher proportion of long chain and MUFAs in its ester structure. This inevitably promotes better ignition quality, lower fuel consumption, enhances superior fuel combustion and performance characteristics and reduced particulate matter emissions.http://www.sciencedirect.com/science/article/pii/S2590123025019437Chlorella micro-algaeMixotrophic-cultureNi-CaO catalystTransesterification reactionSupercritical CO2Biofuel properties
spellingShingle Folayan Adewale Johnson
Bilal Patel
Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
Results in Engineering
Chlorella micro-algae
Mixotrophic-culture
Ni-CaO catalyst
Transesterification reaction
Supercritical CO2
Biofuel properties
title Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
title_full Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
title_fullStr Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
title_full_unstemmed Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
title_short Novel mixotrophic micro-algae oil biodiesel in sustainable clean fuel development
title_sort novel mixotrophic micro algae oil biodiesel in sustainable clean fuel development
topic Chlorella micro-algae
Mixotrophic-culture
Ni-CaO catalyst
Transesterification reaction
Supercritical CO2
Biofuel properties
url http://www.sciencedirect.com/science/article/pii/S2590123025019437
work_keys_str_mv AT folayanadewalejohnson novelmixotrophicmicroalgaeoilbiodieselinsustainablecleanfueldevelopment
AT bilalpatel novelmixotrophicmicroalgaeoilbiodieselinsustainablecleanfueldevelopment