Biomethane and biobutanol production from oil palm wastes: opportunities and challenges of sustainable bioenergy pathways for developing nations

Driven by increasing energy demand fueled by industrialization and population growth, the search for sustainable fuel alternatives has focused on biomass, such as oil palm waste (OPW), which is abundant in tropical countries. This review examines two major bioenergy pathways from OPW: Biomethane and biobutanol. Biomethane, produced from palm oil mill effluent (POME) through anaerobic digestion, presents a viable substitute for natural gas and addresses critical waste management. In contrast, biobutanol is a high-value liquid biofuel produced from lignocellulosic waste such as palm fronds and trunks through acetone-butanol-ethanol (ABE) fermentation. The review compares the technical maturity and economic implications of these two processes. The analysis indicates that while biomethane production is technologically mature (TRL 7–9) and compatible with existing infrastructure, its scaling is often constrained by high capital costs for upgrading and complex logistics. Meanwhile, the commercial viability of biobutanol remains limited by expensive feedstock pretreatment, low fermentation yields, and energy-intensive recovery, rendering widespread production currently uneconomical. Based on this comparative assessment, this review proposes a dual-track strategy by deploying biomethane as a decentralized, immediate solution for energy security, while positioning biobutanol as a long-term, high-potential pathway dependent on future technological advancements. This integrated approach could offer a pragmatic roadmap for the optimal valorization of OPW in developing nations.