Exploration of Lignocellulose-Degrading Bacteria from Sugarcane Bagasse for Potential Bioaugmentation in Biogas Production

Abstract

Indonesia is still highly dependent on fossil fuels, with renewable energy contributing only around 15% of the national energy mix by the end of 2025. This remains far from the national New and Renewable Energy (EBT) policy target of 23% by 2025. One EBT processing potential that has not been fully explored is agro-industrial waste, especially bagasse produced from sugarcane processing. This waste has a high lignocellulose content, so it has great potential to be processed into biogas as an alternative energy source. To increase biogas production from biomass, lignocellulose requires pretreatment. This research uses bioaugmentation technology with indigenous microbes isolated from bagasse in the pretreatment process. This research aimed to obtain indigenous bacterial isolates with lignocellulose-degrading enzyme activity from bagasse. Methods included isolating indigenous bacteria, quantifying bacterial populations, characterizing lignocellulose-degrading bacteria, identifying bagasse bacterial isolates, and performing molecular identification and phylogenetic analysis of the isolates. The results obtained were two bacterial isolates from bagasse samples. Isolate code B showed lignocellulose-degrading activity, with a significant cellulolytic index (IS) of 1.15, indicating its potential as a bioaugmentation candidate for enhancing biogas production.  Based on macroscopic and microscopic observations, the bacterial isolate is suspected to belong to the genus Bacillus sp. Based on sequence analysis using BLAST against the NCBI database and phylogenetic analysis using the Neighbor-Joining method, isolate B was found to belong to the Bacillus subtilis species complex.