{"title":"Agroindustrial Banana Wastes Applied in Biogas Production: Evaluation of Thermal Pretreatment on Alkaline Hydrolysis","authors":"Larissa Ayumi Yamamoto, Ana Gabriela Oliveira Ferreira Janas, Sandra Imaculada Maintinguer","doi":"10.1007/s12155-026-11024-0","DOIUrl":null,"url":null,"abstract":"<div><p>Banana waste is a promising substrate for anaerobic digestion due to its high organic content; however, the recalcitrance of lignocellulosic structures limits hydrolysis efficiency. This study evaluated the effect of alkaline thermal pretreatment of banana waste using sodium hydroxide (NaOH) at concentrations ranging from 0.2% to 3.0%, aiming to enhance carbohydrate solubilization and methane production. Anaerobic batch reactors (1 L) fed with pretreated banana waste in alkaline hydrolysis with NaOH as the main substrate were operated at 37 °C for 15 days under mesophilic conditions, with co-digestion using synthetic sewage. Seven assays were evaluated: assay 1 (0.2% NaOH), assay 2 (0.4% NaOH), assay 3 (0.5% NaOH), assay 4 (1.0% NaOH), assay 5 (2.0% NaOH), assay 6 (3.0% NaOH) and assay 7 (control). The highest carbohydrate release was obtained by assay 1 (0.2% NaOH) with 12,110 mgL<sup>− 1</sup>, whereas untreated waste exhibited the lowest solubilization (4785 mgL<sup>− 1</sup>). The highest cumulative methane production was observed in assay 2 (0.4% NaOH), reaching 2471 mLCH₄Lr<sup>− 1</sup>, while the maximum methane production rate was achieved in assay 1 (0.2% NaOH), with 525.21 mL CH₄ Lr⁻¹ d⁻¹. Carbohydrate removal exceeded 98% in all assays, whereas COD removal ranged from 71.58% to 94.54%. Metagenomic analysis of assay 2 revealed the predominance of <i>Paraclostridium</i> and <i>Clostridium</i> among bacteria and <i>Methanothrix</i> and <i>Methanoregula</i> among archaea, indicating a shift from acetoclastic to hydrogenotrophic methanogenesis. Overall, the management of lignocellulosic biomass, aligned with circular economy principles, promotes the valorization of lignocellulosic agricultural waste into value-added products such as biogas, enhancing resource recovery and sustainability.</p><h3>Graphical Abstract</h3><p>Graphical abstract illustrating the effect of alkaline hydrolysis pretreatment on banana waste anaerobic digestion, highlighting the trade-off between methane production rate and cumulative yield and the associated microbial pathway shifts.</p><div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":487,"journal":{"name":"BioEnergy Research","volume":"19 1","pages":""},"PeriodicalIF":3.3000,"publicationDate":"2026-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12155-026-11024-0.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"BioEnergy Research","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s12155-026-11024-0","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Banana waste is a promising substrate for anaerobic digestion due to its high organic content; however, the recalcitrance of lignocellulosic structures limits hydrolysis efficiency. This study evaluated the effect of alkaline thermal pretreatment of banana waste using sodium hydroxide (NaOH) at concentrations ranging from 0.2% to 3.0%, aiming to enhance carbohydrate solubilization and methane production. Anaerobic batch reactors (1 L) fed with pretreated banana waste in alkaline hydrolysis with NaOH as the main substrate were operated at 37 °C for 15 days under mesophilic conditions, with co-digestion using synthetic sewage. Seven assays were evaluated: assay 1 (0.2% NaOH), assay 2 (0.4% NaOH), assay 3 (0.5% NaOH), assay 4 (1.0% NaOH), assay 5 (2.0% NaOH), assay 6 (3.0% NaOH) and assay 7 (control). The highest carbohydrate release was obtained by assay 1 (0.2% NaOH) with 12,110 mgL− 1, whereas untreated waste exhibited the lowest solubilization (4785 mgL− 1). The highest cumulative methane production was observed in assay 2 (0.4% NaOH), reaching 2471 mLCH₄Lr− 1, while the maximum methane production rate was achieved in assay 1 (0.2% NaOH), with 525.21 mL CH₄ Lr⁻¹ d⁻¹. Carbohydrate removal exceeded 98% in all assays, whereas COD removal ranged from 71.58% to 94.54%. Metagenomic analysis of assay 2 revealed the predominance of Paraclostridium and Clostridium among bacteria and Methanothrix and Methanoregula among archaea, indicating a shift from acetoclastic to hydrogenotrophic methanogenesis. Overall, the management of lignocellulosic biomass, aligned with circular economy principles, promotes the valorization of lignocellulosic agricultural waste into value-added products such as biogas, enhancing resource recovery and sustainability.
Graphical Abstract
Graphical abstract illustrating the effect of alkaline hydrolysis pretreatment on banana waste anaerobic digestion, highlighting the trade-off between methane production rate and cumulative yield and the associated microbial pathway shifts.
The alternative text for this image may have been generated using AI.
期刊介绍：
BioEnergy Research fills a void in the rapidly growing area of feedstock biology research related to biomass, biofuels, and bioenergy. The journal publishes a wide range of articles, including peer-reviewed scientific research, reviews, perspectives and commentary, industry news, and government policy updates. Its coverage brings together a uniquely broad combination of disciplines with a common focus on feedstock biology and science, related to biomass, biofeedstock, and bioenergy production.
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