Background
Lipase is an important microbial enzyme and biocatalyst in biodiesel production. The study investigated fuel properties of biodiesel produced from palm oil (PO) using lipase immobilized on Irvingia gabonensis and calcium alginate.
Results
Biodiesel yield from PO using free and immobilized lipases was highest at 35 °C and pH 7, with product yield using calcium alginate-immobilized lipase, CAIL (94.42, 96.9%) higher than using Irvingia gabonensis-immobilized lipase, IGIL (92.54, 95.8%). Biodiesel produced using immobilized lipases had similar pour point, cloud point, and kinematic viscosity, and they possessed improved fuel properties compared to free lipase biodiesel in terms of densities at 15 °C and flash point. Pour points, flash point, and kinematic viscosity of biodiesel produced using CAIL and IGIL met American and European Standards but density at 15 °C and cloud points are below both standards. CAIL and IGIL biodiesel had similar fatty acid methyl ester (FAME) compounds and consisted more of unsaturated fatty acids (hexadecanoate, 9-octadecenoate, octadecanoate, dodecanoate, and 9,12-octadeca-dienoate) than obtained in biodiesel from free lipase. IGIL and CAIL were re-used in 8 and 12 cycles respectively, with > 90% biodiesel yield achieved in four and 11 cycles.
Conclusions
The study showed that lipase immobilized on Irvingia gabenensis and calcium alginate and used in biodiesel production retained high enzyme activity and biodiesel yield in repeated cycles.
Background: Antibiotic resistance and dearth of novel compounds from natural sources warrants the need to search other environments for potential antibiotic-producing microbial species. The study investigated isolation and identification of antibiotic-producing fungi from pharmaceutical waste sludge. Results: Seven hundred and ninety-seven isolates obtained from sludge of seven pharmaceutical industries in Sango Ota, Ogun State using several growth media, with mould isolates highest (696). Isolated species were from genera Aspergillus (28.55%), Penicillium (18.35%), Trichoderma (13.44%), Rhizopus (10.21%) and Geotrichum (4.01%), and Stachybotrys (0.13%). The CFS of strains named Geotrichum candidum OMON-1, Talaromyces pinophilus OKHAIN-12, and Penicillium citrinum PETER-OOA1 had high reproducible bioactivity against Staphylococcus aureus (32 ± 0.12 mm) and Klebsiella pneumoniae (29 ± 0.12 mm) while P. citrinum MASTER-RAA2 had activity against K. pneumoniae only. Active metabolites were successfully extracted using Diaion HP-20 and methanol:iso-propanol:acetone (6:3:1 v/ v). Antibacterial-active fractions of fungal extract successfully eluted with 40-60% NaCl on ion-exchange chromatography using a cation column. Conclusions: The study successfully screened antibiotic-producing fungal species from pharmaceutical waste storage facilities. Study also showed that similar species from same toxic environment could potentially produce different metabolites.
Environmental implications and the tendency of heavy metals to accumulate in selected tissues of plants and animals, as well as their overall potential to be toxic even at relatively minor levels of exposure, are a source of concern. The use of cheap and effective biological means for heavy metal remediation has been advocated. This study examines the biosorption and bioaccumulation of ferrous ion by Aspergillus terreus (A. terreus) and Trichoderma viride (T. viride) in a batch system. The effects of some important parameters, such as initial metal concentration, temperature and inoculum concentration on biosorption capacity were examined. Langmuir, Freudlinch, Temkin and Dubinin-Radushkevich models were applied to explain the biosorption isotherms of Fe(II) onto the biosorbents. The process fitted well into pseudo first order kinetic model and was best explained by the Langmuir isotherm with maximum absorption capacity of 6.33 and 7.50 mg/g for A. terreus and T. viride, respectively. The calculated thermodynamic parameters (ΔG W , ΔH W and ΔS W ) showed that the biosorption of the ferrous ion to the organisms is feasible, spontaneous and exothermic in nature at low temperature.
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