Recent improvements to ensure sustainability of biodiesel production

A systematic literature review was conducted to investigate the recent contributions to the improvements in biodiesel production. One hundred and ninety-eight research papers were collected through different search engines such as google scholar and Elsevier. The findings were analyzed to identify the improvements and the gaps in the research and what has been currently investigated in biodiesel production, namely, the improvements in the feedstock and the catalyst used. A rising interest in non-edible feedstock has been detected, and several articles have successfully proven some non-edible crops as potential feedstock for biodiesel production. While this is an essential milestone in improving biodiesel production, no literature has been reported on enhancing the availability of these crops, thus ensuring the sustainability of biodiesel production. Most crops used are grown seasonally or in different distant parts of the countries, posing a risk in the sustainability of producing biodiesel from them since their unavailability may result in an inability to produce sufficient biodiesel to meet the world's growing energy demands. The type of catalyst used in biodiesel production has drawn interest, with some studies reporting on none catalyzed transesterification process for biodiesel production and using a non-expensive and environmentally friendly catalyst such as mussel shell catalyst.