Preliminary Data on Monitoring the Fermentation of Liberica Coffee using a Sensor-Integrated Mini Bioreactor
DOI:
https://doi.org/10.25186/.v21i.2420Abstract
Fermentation in bioreactor systems can enhance coffee quality, standardize microbial activity, and improve the reproducibility of specialty coffee production. This study evaluated the performance of a custom mini-bioreactor with real-time gas sensors for monitoring the fermentation of Coffea liberica cherries inoculated with Bacillus cereus. The system continuously measured CO₂, H₂, CH₄, ethanol, temperature, and pH, enabling a comprehensive profiling of fermentation. Sensory evaluation and LC-MS chemical fingerprinting assessed the impact of microbial fermentation on coffee quality. Fermentation with B. cereus (FCB) produced higher levels of CO₂ (545 ppm), H₂ (379.11 ppm), ethanol (472.32 ppm), and CH₄ (1.85 ppm) than fermentations with Leuconostoc
(FBL) and Exiguobacterium indicum (FBE), except for CH₄. LC-MS analysis confirmed that fermentation preserved the core chemical profile of Liberica coffee, with caffeine as the dominant compound. These results show that sensor-integrated bioreactor systems offer a scalable, controllable platform for real-time monitoring and optimization of coffee fermentation.
Key words: Bacillus cereus; coffee fermentation; mini-bioreactor; gas-exhaust.
References
Abd-Alrahman, A. M et al. (2023). Production of natural flavor compounds using Bacillus subtilis-fermented soybean meal extract and their biological potential: a comprehensive in vitro study. Frontiers in Nutrition, 10:1280209.
Araujo, J. B. S. et al. (2021). Decomposition and nutrients released from forest and perennial crops associated with organic coffee. Coffee Science, 16:e161845.
Banti, M., & Atlaw, T. (2024). Effect of processing methods on physicochemical and cup quality of coffee at Jimma, Ethiopia. Heliyon, 10(9):e30480.
Bressani, A. P. P. et al. (2018). Characteristics of fermented coffee inoculated with yeast starter cultures using different inoculation methods. LWT, 92:212-219.
Cheserek, J. J. et al. (2021). Green bean biochemical attributes of Arabusta coffee hybrids from Kenya using HPLC and soxhlet extraction methods. Australian Journal of Crop Science, 15(2):201-208.
Contreras-Jácquez, V. et al. (2021). In-cell crosslinked enzymes: improving bacillus megaterium whole-cell biocatalyst stability for the decarboxylation of ferulic acid. Process Biochemistry, 110:71-84.
Cruz-O’byrne, R. et al. (2021). Microbial diversity associated with spontaneous coffee bean fermentation process and specialty coffee production in northern Colombia. International Journal of Food Microbiology, 354:109282.
Daglia, M. (2012). Polyphenols as antimicrobial agents. Current Opinion in Biotechnology, 23(2):174-181.
Dawidowicz, A. L., & Typek, R. (2017). Transformation of chlorogenic acids during the coffee beans roasting process. European Food Research and Technology, 243(3):379-390.
De Bruyn, F. et al. (2017). Exploring the impacts of postharvest processing on the microbiota and metabolite profiles during green coffee bean production. Applied and environmental microbiology, 83(1):1-16.
De Carvalho Neto, D. P. et al. (2018). Efficient coffee beans mucilage layer removal using lactic acid fermentation in a stirred-tank bioreactor: Kinetic, metabolic and sensorial studies. Food Bioscience, 26:80-87.
De Melo Pereira, G. V. et al. (2019). Exploring the impacts of postharvest processing on the aroma formation of coffee beans - A review. Food Chemistry, 272:441-452.
Elhalis, H. et al. (2020). The crucial role of yeasts in the wet fermentation of coffee beans and quality. International Journal of Food Microbiology, 333:108796.
Elhalis, H., Cox, J., & Zhao, J. (2023). Coffee fermentation: Expedition from traditional to controlled process and perspectives for industrialization. Applied Food Research, 3:100253.
Galarza, G., & Figueroa, J. G. (2022). Volatile compound characterization of coffee (Coffea arabica) processed at different fermentation times using SPME–GC–MS. Molecules, 27(6):2004.
Hadipernata, M.; & Nugraha, S. (2018). Process technology of luwak coffee through bioreactor utilization. IOP Conference Series: Earth and Environmental Science, 102:012092.
International Coffee Organization - ICO. (2022). Annual Review Coffee Year 2021/2022. . https://ico.org/annual-review/
Jumhawan, U. et al. (2015). Application of gas chromatography/flame ionization detector-based metabolite fingerprinting for authentication of Asian palm civet coffee (Kopi Luwak). Journal of Bioscience and Bioengineering, 120(5):555-561.
Jumhawan, U. et al. (2013). Selection of discriminant markers for authentication of asian palm civet coffee (Kopi Luwak): A metabolomics approach. Journal of Agricultural and Food Chemistry, 61(33):7994-8001.
Latief, M. et al. (2023). Coffee improvement by wet fermentation using lactobacillus plantarum: sensory studies, proximate analysis, antioxidants, and chemical compounds. Jurnal Rekayasa Kimia & Lingkungan, 18(2):134-148.
Lee, L. W. et al. (2015). Coffee fermentation and flavor - An intricate and delicate relationship. Food Chemistry, 185:182-191.
Li, Qin et al. (2021). Improving the catalytic characteristics of phenolic acid decarboxylase from Bacillus amyloliquefaciens by the engineering of N-terminus and C-terminus. BMC Biotechnology, 21(1):44.
Magalhães Júnior, A. I. et al. (2021). A critical techno-economic analysis of coffee processing utilizing a modern fermentation system: Implications for specialty coffee production. Food and Bioproducts Processing, 125:14-21.
Martinez, S. J. et al. (2021). Novel stainless steel tanks enhances coffee fermentation quality. Food Research International, 139:109921.
Miñón-Fuentes, R., & Aguilar-Juárez, O. (2019). Hydrogen production from coffee pulp by dark fermentation. Water science and technology: A journal of the International Association on Water Pollution Research, 80(9):1692-1701.
Moreno Cárdenas, E. L. et al. (2020). Modeling dark fermentation of coffee mucilage wastes for hydrogen production: artificial neural network model vs. fuzzy logic model. Energies, 13(7):1663.
Neto, D. P. de C. et al. (2020). Microbiological , physicochemical and sensory studies of coffee beans fermentation conducted in a yeast bioreactor model. Food Biotechnology, 34(2):172-192.
Ollennu-Chuasam, P. et al. (2024). Lipophilic and hydrophilic metabolites as descriptors of different coffee beverages. Journal of agricultural and food chemistry, 72(29):16461-16474.
Pereira, G. V. de M. et al. (2017). Microbial ecology and starter culture technology in coffee processing. Critical Reviews in Food Science and Nutrition, 57(13):2775-2788.
Pisponen, A., & Andreson, H. (2024). The impact of lactic acid bacteria and yeasts ratio on fermentation and taste of kvass. Agronomy Research, 22:513-522.
Putri, S. P. et al. (2015). Application of GC / MS and GC / FID-based metabolomics for authentication of Asian palm civet coffee (Kopi Luwak). Metabolomics, 3(2):34-41.
Renaudie, M. et al. (2024). Spontaneous dark fermentation in a pre-seeded liquid-gas membrane bioreactor: Impact of wine and coffee biowaste microflora on continuous biohydrogen production. Journal of Cleaner Production, 437:140759.
Reyes, E. I. M. et al. (2024). Controlled fermentation in artisanal bioreactors to produce specialty coffees. Ciência e Agrotecnologia, 48:e007524.
Salengke, S. et al. (2019). Technology innovation for production of specialty coffee. IOP Conference Series: Earth and Environmental Science, 355:012105.
Shah, P. et al. (2024). Chapter 9 - Anaerobic fermentation for biogas production. In M. Jeguirim., & A. A. Zorpas, (Eds.) Advances in biofuels production, optimization and applications. [S.l.]: Elsevier, (pp.165-183).
Sharma, R. et al. (2020). Microbial Fermentation and Its Role in Quality Improvement of Fermented Foods. Fermentation, 6(4):106.
Silva, L. C. F. et al. (2024). Enhancing sensory quality of coffee: the impact of fermentation techniques on Coffea arabica cv. Catiguá MG2. Foods, 13(5):653.
Somporn, C. et al. (2011). Effects of roasting degree on radical scavenging activity, phenolics and volatile compounds of Arabica coffee beans (Coffea arabica L. cv. Catimor). International Journal of Food Science and Technology, 46(11):2287-2296.
Sridevi, V. et al. (2024). Challenges and opportunities in the production of sustainable hydrogen from lignocellulosic biomass using microwave-assisted pyrolysis: A review. International Journal of Hydrogen Energy, 52:507-531.
Tarigan, I. L. et al. (2024a). Changes in the chemical compound and sensory profiles of liberica fermentation (Coffea liberica) with Cellulolytic Bacteria Alcaligenes sp and Exiguobacterium indicum. Coffee Science, 19:e192258.
Tarigan, I. L. e et al. (2024b). Enhancement of liberica coffee quality by wet fermentation using Bacillus subtilis. ALCHEMY Jurnal Penelitian Kimia, 20(2):162-177.
Toci, A. T.; & Farah, A. (2008).Volatile compounds as potential defective coffee beans’ markers. Food Chemistry, 108(3):1133-1141.
Tolentino Vaz, C. J. et al. (2022). Effect of fermentation of arabica coffee on physicochemical characteristics and sensory analysis. Research Square, 2022:1-14.
Towaha, J., & Rubiyo, R. (2016). Physical quality and flavor of arabica coffee beans fermented by probiotic microbes from civet digestive system. Jurnal Tanaman Industri dan Penyegar, 3(2):61.
Zhang, T. et al. (2021). Improvement of coffee grounds high solid thermophilic methane fermentation by co-digestion with in-situ produced waste activated sludge: Performance and stability. Science of The Total Environment, 765:142551
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Coffee Science - ISSN 1984-3909The copyright of the articles published in this journal belongs to the authors, with the journal holding the first publication rights. As the articles are published in this journal under open access, they may be freely used, with proper attribution, for educational and non-commercial purposes
