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Like many countries, Indonesia generates large quantities of food waste. Food waste is poorly managed due to inadequate treatment practices, which has a harmful impact on the environment. This paper demonstrates the high potential for food waste valorization in Indonesia and outlines the optimal valorization pathways to inform future decision-making surrounding the management of this waste. This paper also compares various conversion technologies for transforming food waste into liquid, solid, and gaseous biofuels. The challenges and opportunities for wider implementation are also considered, including the integration of supply chains and the logistics of food waste management, the technological feasibility, and the persistent behaviors surrounding food waste and energy in Indonesia. The economic and environmental benefits, the perspectives of improved food waste management practices and sustainable fuels, as well as the policy landscape surrounding waste and sustainable energy are also explored. The challenges of scalability and commercialization are also highlighted in this paper. This review demonstrates the best pathways from food waste valorization to bioenergy, including biogas or biodiesel integrated with a black soldier fly larvae (BSFL) composting system. Despite the scale of resources in Indonesia, the pathways and technologies for processing food waste are lacking. Further in-depth studies are required to demonstrate the sustainability and feasibility of food waste transformation into bioenergy to realize its high value.

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Marine biomass (such as wild seaweed Gracilaria verrucosa) is highly abundant in Indonesia and has been highlighted as a potential biomass resource for bioenergy production. Furthermore, agro-industrial waste (such as tofu dregs/TD which arises from large scale production in the country) is rich in carbohydrates and proteins, and is therefore considered a viable feedstock for production of high-value added products. This study aimed to investigate the co-digestion of wild seaweed G. verrucosa (WGv) with TD and its impacts on biogas and methane production. The biochemical methane potential (BMP) test was operated for 28 days at temperature of 37 o C. The co-digestion of WGv with TD at 90:10 and 80:20 ratios significantly increased the specific methane potential (SMP), giving an average of 98 LCH4/kgVS and 120 L CH4/kgVS, respectively. Addition of co-digestion substrates promoted co-metabolism in the digesters, increasing the ability of the microorganism to effectively digest the organic matter present in the feedstock's mixture. The washing pre-treatment reduced the concentration of inorganic compounds and salts within the wild seaweed G. verucosa, leading to an improvement in biogas and methane yield. The mass balance illustrated that this process configuration led to a reduction in the quantity of digestate to be managed (i.e. dewatering, transport, and land/soil application). This will subsequently reduce the cost and energy requirements for sludge management, estimated at 37%. Therefore, the co-digestion of WGv with TD and the application of a washing pre-treatment stage prior to AD can positively enhance biogas and methane production. Indepth investigation for optimal valorisation using AD technology is highly essential.

Production of biogas from lignocellulosic biomass by anaerobic digestion (AD) has attracted much interest. Oil palm empty fruit bunches (OPEFB), one of lignocellulosic biomass, is highly abundant in Indonesia and has potential as feedstock for bioenergy production such as biogas or methane. Yet, pre-treatments are needed to improve biogas production due to its complex crystalline structures. Chemical pre-treatments with acid or alkaline solution were reported to increase cellulose or highly reduce the lignin content of OPEFB. This study aimed to evaluate the effect of acid and alkaline pre-treatments on the characteristics of OPEFB and methane potential. The acid pre-treatment experimental design was used factor of H2SO4 concentration (1, 1.3, and 1.6 (%v/v)) and NaOH concentration (1.8, 2.8, and 3.8 (%w/v)). Methane potential evaluation was carried out using the biochemical methane potential (BMP) test with the Automatic Methane Potential Test System (AMPTS) II under mesophilic condition (37°C), operated for 28 days. The results showed that both dilute acid and alkaline pre-treatment positively impact altering the characteristics of OPEFB, hence the specific methane potential. Alkaline pre-treatment with NaOH 3.8 (%w/v) gave the highest average SMP value of 0.161 ± 0.005 m3 CH4/kgVSadded.