Immobilization of lipase and biodiesel production from fishery and animal processing waste
Bibliographic record
Abstract
Biodiesel (BD) is conventionally produced by the transesterification of vegetable oils or animal fats with a monohydric alcohol and base catalyst, and known for its many technical and environmental advantages over petrodiesel. However, these oils are not economically viable feedstock due to their value as edible oils. Alternative, inexpensive feedstocks with minimal to no food value such as the large quantities of fishery and animal processing by-products which are often discarded as waste were explored in this project. Lipase was investigated as an alternative to chemical catalyst due to the tolerance of the former to a wide variety of feedstocks and simpler post-production processes among other advantages. Approximately 23.32-61.53% (on dry weight basis) of salmon skin oil (SSO) was recovered by the various solvent extraction systems evaluated. The quality of SSO stored at 25, 4, -18, and -80oC were assessed over time (1- 45 days) with respect to changes in the fatty acid profile, free fatty acid (FFA) content, peroxide value, and thiobarbituric acid reactive substances. A Fourier transform infrared (FTIR) spectroscopic method was assessed as an alternative to the conventional AOCS titrimetric method for the determination of FFA content. With modifications, the new method was found to be capable of responding linearly to oleic acid (0-6.5%) addition, producing a FFA calibration equation with a S.D. of ±0.014% FFA. Based on the results from the initial assessment of the effects of temperature (25-65oC), oil:alcohol molar ratio (1:1-1:6), alcohol type (ethanol/methanol), and time (8-120 h) on Lipozyme®-IM-catalyzed transesterification of the recovered SSO, a commercial blend of yellow grease and rendered animal fat, and olive oil to fatty acid ethyl ester (FAEE) for use as BD, the process was considered for optimization. In three experiments, the linear, quadratic, and bilinear effects of the reaction variables on FAEE yield were assessed with response surface methodology (RSM) based on central composite rotatable design (CCRD). In each experiment, second-order polynomial models fitted to FAEE yield provided response surfaces at the various reaction times (8-48 h). These models were generally significant and produced reliable and stable predictions. The optimum conditions were found to be close to the centre point of the reaction variables. A high performance liquid chromatography unit equipped with a size exclusion column, and a refractive index detector was used for the simultaneous separation, identification, and quantitation of the reaction components; FAEE, unreacted triacylglycerol, residual diacyl- and monoacylglycerol, and alcohol as well as FFA. The transesterified oils were also tested for various fuel properties. To expand the uses of lipase recovered from fish processing discards to include catalyst for BD production, lipase from crude preparations of delipidated grey mullet (Mugil cephalus) viscera were isolated on para-aminobenzamidine agarose and immobilized on octyl Sepharose CL-4B (o-Sep). A signal in the amide I absorption region of the FTIR spectrum was attributed to the protein layer on o-Sep. Immobilized grey mullet lipase (GMLi) had a 10°C higher optimum temperature compared to the free enzyme (GML) for the hydrolysis of para-nitrophenyl palmitate. Immobilization lowered the enthalpy of activation (ÎH*), and free energy of activation (ÎG*) by more than 313 and 1315 cal/mol, respectively, while it enhanced the reusability, thermal, storage, and organic solvent stabilities of GML.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".