Efficient utilization and management of seaweed biomass for biogas production

The global trend of seaweed production and their biomass utilization for biofuels generation is increased due to the high carbohydrate and protein content. Anaerobic digestion (AD) is a promising technology to convert organic compounds of seaweed biomass into biogas. However, a comprehensive review enclosing the biomethane potential, process parameters, microbial shifts, and effective approaches to enhance the digestibility and biogas production from seaweeds has not been reported. Thus, this article aims to explore, classify, and comprehensively present the potential of seaweeds for biogas production. The global trend of biofuels including biogas production from seaweed biomass is elucidated. The effect of seasonal variations on the biochemical composition of seaweeds is highlighted. The microbial community involved in AD of seaweeds is discussed. This article also covers the pretreatments, co-digestion, supplementation of additives, and sequential utilization of seaweeds to enhance biogas production. The seasonal variations significantly affected the composition of seaweeds and subsequently altered the content of inhibitory compounds. The application of different strategies (such as pretreatment) mitigated the effect of inhibitors and boosted biogas production. Firmicutes and Bacteroidetes were reported to be the major bacteria and Methanobacteriales were the dominant archaea during the digestion of seaweeds. Extensive research on microbial dynamics and the application of co-digestion is still needed to achieve complete utilization of biomass coupled with biogas enhancement.