| Expressing lipase source | Substrate | Acyl acceptor | Yield | Reference |
|---|---|---|---|---|
| Serratia marcescens YXJ-1002 | Waste grease | Methanol | 97% | [183] |
| Rhizomucor miehei and Penicillium cyclopium | Soybean oil | Methanol | >95% | [184] |
| Fusarium heterosporum | Soybean oil | Methanol | 95% | [185] |
| Rhizomucor miehei (RML) | Soybean oil | Methanol | 83.14% | [186] |
| Microalgal oil | Methanol | >90% | [187] | |
| Thermomyces lanuginosus (Tll) | Waste cooking oil | Methanol | 82% | [176] |
| Rhizopus oryzae IFO4697 | Soybean oil | Methanol | 71% | [188] |
Table 1.7 Investigation of immobilized whole-cell biocatalysts to produce biodiesel.
| Lipase cell factory | Immobilized on | Substrate | Acyl acceptor | Yield | Reference |
|---|---|---|---|---|---|
| Rhizopus oryzae cells | Biomass support particles | Soybean oil | Methanol | 70%–83% | [197] |
| Mucor circinelloides | Poly-Urethane Foam | Sardine (Sardinella lemuru) oil | Methanol | NA | [198] |
| Mucor circinelloides URM 4182 | polyurethane support | Babassu oil | Ethanol | 98.1% | [199] |
| Rhizopus oryzae IFO4697 | biomass support particles | Oleic acid | Methanol | 90% | [200] |
| Soybean oil | Methanol | 72% | |||
| Rhizopus oryzae (ROL) | biomass support particles | Jatropha curcas oil | Methanol | 90% | [201] |
| Soybean oil | Methanol | 90% | [202] | ||
| Rhizopus oryzae 262 | Calcium alginate beads | waste cooking oil (sunflower oil) | Methanol | 84% | [203] |
| Rhizopus oryzae ATCC 34612 | biomass support particles | Cottonseed oil | Methanol | 27.9% | [204] |
| Pseudomonas fluorescens MTCC 103 | Sodium alginate | Jatropha oil | Methanol | 72% | [205] |
| Aspergillus niger | Biomass support particles | Palm oil | Methanol | >90% | [104] |
1.11 Recent Strategies to Improve Biodiesel Production
1.11.1 Combination of Lipases
Lipases from different sources or organisms possess different properties. Just like no ideal gas really exists, similarly, there is no ideal lipase that will be considered as absolutely perfect. Just one lipase cannot have all properties that are ideally required for optimal biodiesel production. But researchers are trying to find the best among the lot. Novel sources provide different features of lipase that can be good for biodiesel production. Some lipases are good at tolerating high temperatures, some may work at low temperature, some provide a good temperature range, some may have good catalytic activity, and some may have good hydrolytic activity. Raw material or substrate that is used for biodiesel production is very diverse in nature. Feedstock is mainly comprised of FFA, triglycerides, diglycerides, or monoglycerides, so it is difficult for one lipase to tackle all these things with best possibility. Likewise, every lipase has different alcohol inhibition capacity to tolerate it. So, all in all, these things make it very difficult for one lipase to be perfectly suitable to give best results. So, researchers have come with an idea to use combination of enzymes/lipases. One may be best at providing specific feature and other may be good at giving another specific feature and so on. This way combination of enzymes will provide many features that will be good for biodiesel production. A lot of combination of enzymes have been studied recently for biodiesel production. According to Li et al. [206], combined use of Lipozyme TL IM and Novozym 435 lipase resulted in 96.38% conversion of stilingia oil into FAME. Reaction conditions were methanol-to-oil molar ratio (6.1:4), temperature 20°C along with the use of co-solvent consisting of acetonitrile and t-butanol. At these conditions even after 30 cycles, there was no loss in lipase activity. Similarly, many investigations have been done and some of them are given in
