Production of Bioethanol from Pretreated Compost Substrate Using Thermophilic bacteria

Bioethanol is an organic biofuel that is obtained from lignocellulosic biomass, a renewable substrate that through a process of numerous unit operations could be converted in an ethanol solution with high purity grade. This study investigated the production of bio-ethanol from pretreated compost substrate using thermophilic bacteria, addressing the growing need for sustainable biofuel alternatives. Soil samples were collected from three locations within Ekiti State University, Nigeria, and bacteria were isolated using serial dilution and pour plate methods. Compost samples from piggery, chicken, and palm kernel sources underwent a 10-day aerobic pretreatment process at 37°C to enhance substrate accessibility. Bacterial isolates were used to ferment pretreated compost. Glucose fermentation experiments were conducted to assess ethanol production potential. Results showed successful isolation of bacteria with colony-forming units ranging from 104 to 106 CFU/g. This study highlights the use of locally sourced thermophilic bacteria for fermenting pretreated compost for bio-ethanol production. The approach shows promise for valorizing organic waste streams while producing renewable energy. However, further optimization of pretreatment and fermentation processes, along with scale-up studies are required. The GC-MS analysis showed that bio-ethanol concentrationsin chicken compost were highest at 75%, piggery compost consistently around 73% and palm kernel compost ranged from 35% to 53%. The FT-IR spectrum of palm kernel compost revealed key functional groups, indicating the presence of organic compounds and decomposed materials.