Biodiesel production from rice bran oil using immobilized lipase biocatalyst | |
| Author | Nantaprapa Nantiyakul |
| Call Number | AIT Thesis no.FB-07-10 |
| Subject(s) | Rice oil Biodiesel fuels Lipase |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. FB-07-10 |
| Abstract | Biodiesel or fatty acid methyl esters (FAME) can be produced by transesterification of triglycerides with methanol in the presence of different catalysts (chemicals and enzymes). Lipase-catalyzed mcthanolysis offers an environmentally friendly method for the biodiesel production. In this study, methyl esters were produced by transesteritication of various types of rice bran oil (commercial refined,-partially refined, crude, high acid, and waste cooking rice bran oil) using immobilized lipase as a catalyst. Parameters like enzyme pretreatment, types of catalyst, types of rice bran oil, methanol content, incubation time, and methods of methanolysis that affect methyl ester formation were analyzed. The highest FAME content of 84.84±1.37% was obtained from methanolysis of commercial refined rice bran oil in the presence of pretreated Novozyme 435 5% by wt. in tert-butanol and the subsequent substrate (RBO). The best molar ratio of methanol to oil was 4.5: 1. The optimal incubation time for the reaction was 24 hours at 50 °C. Stability of the enzyme was retained at more than 80% FAME content after six batches of reuse. Moreover, waste cooking rice bran oil also produced FAME content as high as 82.14+3.12%. This indicated that it can be used effectively as substrate for biodicsel production. Alkali-catalyzed methanolysis of rice bran oil produced 95.55±2.15% FAME content, which was significantly higher than that of lipase process. High free fatty acid content in crude rice bran oil however decreased FAME formation in alkali-catalyzed methanolysis to 1.17±0.42%. The water requirement for washing and the environmental impacts of the alkali-catalyzed process need to be taken into account. A bioreactor was used to scale up the biodiesel production of lipase-catalyzed methanolysis. Maximum FAME contents from 500 g RBO batch for lipase-catalyzed methanolysis and alkalicatalyzed methanolysis were 77.62±0.11% and 95.30±0.07% respectively. In addition, better mixing characteristic of bioreactor for lipase-catalyzed process is required for obtaining higher FAME content. Property analysis showed that transesteritication reaction improved properties and characteristics of the obtained biodiesel as compared with the untreated oil. Both lipase- and alkali-catalyzed process produced similar biodiesel properties. Density at 15°C was 883 kg/m³. Viscosity at 40 °C ranked between 4.7-5.0 cSt. Flash point was more than 102.5 °C. There was no sulphur content in the produced biodiesel. Carbon residue was between 0.02-0.05% wt. No water and sediment were found. No corrosion occurred in the copper strip corrosion test. Acid number of alkali-catalysis biodiesel was 0.17 mg KOH/g while it was "nil" for lipase-catalysis biodiesel. Pour point was in the range of 3-6 °C. All of these properties were as per biodicsel specifications. Hence, lipase- and alkali-catalyzed methanolysis successfully produced biodiesel that can be used effectively in diesel engines. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. FB-07-10 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Rakshit, Sudip Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Dutta, Animesh; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |