Enhancing Methane Production from Lignocellulosic Waste through Optimized Operational Strategies in Anaerobic Co-Digestion: Cotton Stalks as a Case Study
Keywords:
Cotton stalks, Azolla, Cow manure, Biogas productionAbstract
Cotton stalks (CS) are a lignocellulosic biomass that pose challenges for anaerobic digestion (AD) due to their high lignin content, which leads to long digestion periods, inhibits hydrolysis, limits biodegradability, and produces low methane yields. One successful method to overcome these limitations is co-digestion, which involves mixing cotton stalks with different substrates. For this reason, a thermostatic stainless-steel water bath and a ten-batch system of biodigesters were designed, established, and implemented at the Biochemistry Laboratory, Water and Soil Science Department, Faculty of Technology and Development, Zagazig University (Egypt). Azolla (AZ) and cow manure (CM) were used for different mixing ratios with cotton stalks to evaluate how different substrate mixtures influence biogas production and its methane content. Ten experimental mixtures were conducted: mixture1 (100% CS), mixture2 (100% CM), mixture3 (100% AZ), mixture4 (75% CS + 25% CM), mixture5 (50% CS + 50% CM), mixture 6 (25% CS + 75% CM), mixture7 (75% CS + 25% AZ), mixture8 (50% CS + 50 % AZ), mixture 9 (25% CS + 75% AZ) and mixture10 (CS:CM:AZ = 1:1:1). Experiments were performed under controlled conditions with daily biogas measurements and methane concentration, calorific value estimation, and chemical analysis of influent and effluent throughout digestion. Notably, mixture 10 yielded superior biogas production compared to mixtures 1 through 9, with increases of 56.13%, 35.92%, 43.45%, 32.21%, 21.65%, 21.12%, 13.54%, and 7.91%, respectively, except for mixture 3, which exceeded it by 13.85%. Among all mixtures, mixture 3 showed the highest methane concentration, while others ranged between 37.85% and 71.49%. The statistical analysis of both cumulative biogas and methane production showed a highly significant effect at p < 0.001. The R² reached 1.0 for cumulative biogas production and 96.9% for methane production, indicating clear and well defined differences among the treatments
Downloads
References
[1] Abdellatif, S. M., El-Hadidi, Y. M., & El-Kasemy, S. W. (2021). Effect of Aeration Rates and Mechanical Stirring System on Compost Production from Some Farm Wastes. Journal of Soil Sciences and Agricultural Engineering, 12(11), 831-838.
[2] Abdellatif, S. M., El-Hadidi, Y. M., & Nazmi, N. T. (2020). Effect of Digestion Temperature and Stirring Time on Biogas Properties Using Vertical and Horizontal Units. Journal of Soil Sciences and Agricultural Engineering, 11(11), 677-685.
[3] Adelekan, B. A. and Bamgboye, A. I. (2009). Comparison of biogas productivity of cassava peels mixed in selected ratios with major livestock waste types. African Journal of Agricultural Research. 4(7), 571-577.
[4] Ahmed, A., Bakar, M. S. A., Hamdani, R., Park, Y. K., Lam, S. S., Sukri, R. S., ... and Aslam, M. (2020). Valorization of underutilized waste biomass from invasive species to produce biochar for energy and other value-added applications. Environmental Research, 186, 109596.
[5] Ahmed, B., Aboudi, K., Tyagi, V. K., Álvarez-Gallego, C. J., Fernández-Güelfo, L. A., Romero-García, L. I., and Kazmi, A. A. (2019). Improvement of anaerobic digestion of lignocellulosic biomass by hydrothermal pretreatment. Applied Sciences, 9(18), 3853.
[6] AOAC) 2023(. Official Methods of Analysis Method 973.48. Ch. 4, p. 15. AOAC International, Rockville, Md.
[7] APHA (American Public Health Association), AWWA, WEF) 2023(. Standard Methods for the Examination of Water and Wastewater. 24th ed. Washington, D.C., USA.
[8] Dai, X., Hua, Y., Dai, L., and Cai, C. (2019). Particle size reduction of rice straw enhances methane production under anaerobic digestion. Bioresource technology, 293, 122043.
[9] Doyeni, M. O., Stulpinaite, U., Baksinskaite, A., Suproniene, S., and Tilvikiene, V. (2021). The effectiveness of digestate use for fertilization in an agricultural cropping system. Plants. 10(8), 1734.
[10] Ebrahim, N. M., Mahmoud, S. M., Ahmed, S. M., EL-Shahat, R. M., & Mohamed, H. M. (2024). Azolla as a source of organic nitrogen and its role in recycling agricultural residues and improving the quality of compost. Assiut Journal of Agricultural Sciences, 55(2), 246-259.
[11] Eduok, S., John, O., Ita, B., Inyang, E., and Coulon, F. (2018). Enhanced biogas production from anaerobic co-digestion of lignocellulosic biomass and poultry feces using source separated human urine as buffering agent. Frontiers in Environmental Science, 6, 67.
[12] Elfar, S. E. (2022). Biogas Production from Date Palm Leaves. Journal of Soil Sciences and Agricultural Engineering, 13(12), 387-391.
[13] El-Hadidi, Y., El-Bakhshwan, M., and Mohamed, M. (2016). Effect of High Total Solids Concentration on Biogas Production from Cattle Dung. Journal of Soil Sciences and Agricultural Engineering, 7(10), 783-792.
[14] Goodman, B. A. (2020). Utilization of waste straw and husks from rice production: A review. Journal of Bioresources and Bioproducts, 5(3), 143-162.
[15] Kovačić, Đ., Kralik, D., Jovičić, D., Rupčić, S., Popović, B., and Tišma, M. (2018). Thermal pretreatment of harvest residues and their use in anaerobic co-digestion with dairy cow manure. Applied biochemistry and biotechnology, 184, 471-483.
[16] Kriswantoro, J. A., Pan, K. Y., and Chu, C. Y. (2024). Co-digestion approach for enhancement of biogas production by mixture of untreated napier grass and industrial hydrolyzed food waste. Frontiers in Bioengineering and Biotechnology, 11, 1269727.
[17] Kumar, V., Kumar, P., Kumar, P., & Singh, J. (2020). Anaerobic digestion of Azolla pinnata biomass grown in integrated industrial effluent for enhanced biogas production and COD reduction: Optimization and kinetics studies. Environmental Technology & Innovation, 17, 100627.
[18] Li, D., Liu, S., Mi, L., Li, Z., Yuan, Y., Yan, Z., and Liu, X. (2015). Effects of feedstock ratio and organic loading rate on the anaerobic mesophilic co-digestion of rice straw and cow manure. Bioresource Technology. 189, 319-326.
[19] Li, P., He, C., Cheng, C., Jiao, Y., Shen, D., and Yu, R. (2021). Prediction of methane production from co-digestion of lignocellulosic biomass with sludge based on the major compositions of lignocellulosic biomass. Environmental Science and Pollution Research, 28, 25808-25818.
[20] Liu, C., Wachemo, A. C., Tong, H., Shi, S., Zhang, L., Yuan, H., and Li, X. (2018). Biogas production and microbial community properties during anaerobic digestion of corn stover at different temperatures. Bioresource technology, 261, 93-103.
[21] Luo, L., Qu, Y., Gong, W., Qin, L., Li, W., and Sun, Y. (2021). Effect of particle size on the aerobic and anaerobic digestion characteristics of whole rice straw. Energies. 14(13), 3960.
[22] Mao, C., Feng, Y., Wang, X., and Ren, G. (2015). Review on research achievements of biogas from anaerobic digestion. Renewable and sustainable energy reviews. 45, 540-555.
[23] Mir, M. A., Ram, S., Hussain, A., Wani, A., & Kumar, N. (2019). Effect of Azolla addition on enhanced anaerobic digestion of food waste and activated sludge by varying hydraulic retention time (HRT) and organic loading rate (OLR) by using UASB technology. Biochemical & Cellular Archives, 19(2).
[24] Mothe, S., and Polisetty, V. R. (2021). Review on anaerobic digestion of rice straw for biogas production. Environmental Science and Pollution Research, 28, 24455-24469.
[25] Muhayodin, F., Fritze, A., Larsen, O. C., Spahr, M., & Rotter, V. S. (2021). Co-digestion of rice straw with cow manure in an innovative temperature phased anaerobic digestion technology: performance evaluation and trace elements. Energies, 14(9), 2561.
[26] Qian, S., Chen, L., Xu, S., Zeng, C., Lian, X., Xia, Z., & Zou, J. (2025). Research on methane-rich biogas production technology by anaerobic digestion under carbon neutrality: A review. Sustainability, 17(4), 1425.
[27] Rodríguez-Jiménez, L. M., Pérez-Vidal, A., and Torres-Lozada, P. (2022). Research trends and strategies for the improvement of anaerobic digestion of food waste in psychrophilic temperatures conditions. Heliyon, 8(10).
[28] Santhiya, B. and Jeeva, S. (2022). Azolla as a source of biofertilizer for sustainable crop production – a review. Journal of Xi’an Shiyou University, Natural Science Edition.18, 11, 598-605.
[29] Sawatdeenarunat, C., Surendra, K. C., Takara, D., Oechsner, H., and Khanal, S. K. (2015). Anaerobic digestion of lignocellulosic biomass: challenges and opportunities. Bioresource technology, 178, 178-186.
[30] Shi, X., Guo, X., Zuo, J., Wang, Y., and Zhang, M. (2018). A comparative study of thermophilic and mesophilic anaerobic co-digestion of food waste and wheat straw: Process stability and microbial community structure shifts. Waste Management, 75, 261-269.
[31] Wang, J., Liu, S., Feng, K., Lou, Y., Ma, J., and Xing, D. (2025). Anaerobic digestion of lignocellulosic biomass: Process intensification and artificial intelligence. Renewable and Sustainable Energy Reviews. 210, 115264.
[32] Wang, X. J., Yang, G. H., Feng, Y. Z., and Ren, G. X. (2012). Potential for biogas production from anaerobic co-digestion of dairy and chicken manure with corn stalks. Advanced Materials Research, 347, 2484-2492.
[33] Xin, L., Guo, Z., Xiao, X., Xu, W., Geng, R., and Wang, W. (2018). Feasibility of anaerobic digestion for contaminated rice straw inoculated with waste activated sludge. Bioresource technology, 266, 45-50.
[34] Xu, N., Liu, S., Xin, F., Zhou, J., Jia, H., Xu, J., ... and Dong, W. (2019). Biomethane production from lignocellulose: Biomass recalcitrance and its impacts on anaerobic digestion. Frontiers in bioengineering and biotechnology, 7, 191.
[35] Yan, X., Deng, P., Ding, T., Zhang, Z., Li, X., and Wu, Z. (2023). Effect of temperature on anaerobic fermentation of poplar ethanol wastewater: performance and microbial communities. ACS omega. 8(6), 5486-5496
Downloads
Published
How to Cite
Issue
Section
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
You are free to:
- Share — copy and redistribute the material in any medium or format
- Adapt — remix, transform, and build upon the material for any purpose, even commercially.
Terms:
- Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
- No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.
