Table 2
Various generations of biofuel with processing technology.
| Generation | Biomass used | Processing methodology | Generated fuel | Ref. |
|---|---|---|---|---|
| 1st | Food crops, edible oil/animal fats | Transesterification – Thermochemical processing | Bioethanol, biodiesel. | [16, 18] |
| 2nd | Waste cooking oil, rice/wheat straw, non-edible oils | Pre-treatment – Chemical, biological, physical, fermentation and thermochemical processing | Syngas, biobutanol, biodiesel. | [23, 27] |
| 3rd | Algae and microorganisms | Cultivation – Extraction – Fermentation – Thermochemical processing | Methane, bioethanol, biobutanol, syngas, biodiesel. | [33, 34, 39] |
| 4th | Algae and microorganisms | Metabolic engineering of algae capable of absorbing biomass – Cultivating – Fermentation – Thermochemical processing | Biodiesel, methane, biobutanol, bioethanol. | [45–47] |