Ahamefule Chukwuemeka Samson, Osilo Chidimma, Ahamefule Blessing C, Madueke Stella N, Moneke Anene N
Department of Microbiology, University of Nigeria, Nsukka 410001, Nigeria.
Department of Applied Microbiology, Faculty of Biosciences, Nnamdi Azikiwe University, Awka, Nigeria.
Curr Res Microb Sci. 2024 Nov 15;7:100305. doi: 10.1016/j.crmicr.2024.100305. eCollection 2024.
Pollution from fossil fuel usage coupled with its unsustainability is currently instigating a global drive for affordable and eco-friendly alternatives. A feasible replacement seems to be microbial biofuels. However, the production cost is still high, partly due to the cost of substrates and media. Microalgae, yeasts, moulds and bacteria can grow on cheap and easily available agricultural waste substrates to produce bioethanol, biogas, biobutanol, acetone and/or lipids for biodiesel. Oleaginous microbes, such as several species of etc., have been applied in the production of high and choice lipids for biodiesel. High bioethanol, butanol and acetone yields have also been achieved with several agricultural waste substrates either through separate hydrolysis and fermentation or simultaneous saccharification and fermentation. The isolation or transformation of some microbial strains has shown the possibility of using only one microorganism to produce bioethanol from lignocellulose biomass in consolidated bioethanol production. High biogas/biomethane yield has also been recorded from different agricultural wastes, especially in co-digestion systems. Pre-treatment, detoxification, application of microbial co-cultures, co-substrate mixing ratios, organic loading rate, hydraulic retention time among others have been reported to affect the quantity and quality of different biofuels produced from agricultural wastes. Interestingly, these agricultural waste substrates were greatly degraded during fermentation and/or digestion to achieve high level of bioremediation. Therefore, this study presents a holistic review of various agricultural wastes adopted as biofuel substrates, the conditions to attain optimum biofuel productions and cases of simultaneous bioremediation of substrates obtained during biofuel production. The valorization of the biofuel by-products into other essential products to achieve a zero-waste and circular bioeconomy is also properly presented.
化石燃料使用带来的污染及其不可持续性，目前正在推动全球范围内对经济实惠且环保替代品的探索。一种可行的替代方案似乎是微生物生物燃料。然而，其生产成本仍然很高，部分原因在于底物和培养基的成本。微藻、酵母、霉菌和细菌可以在廉价且易于获取的农业废弃物底物上生长，以生产生物乙醇、沼气、生物丁醇、丙酮和/或用于生物柴油的脂质。产油微生物，如几种 等，已被应用于生产用于生物柴油的优质脂质。通过单独水解和发酵或同时糖化和发酵，使用几种农业废弃物底物也实现了高生物乙醇、丁醇和丙酮产量。一些微生物菌株的分离或改造表明，在联合生物乙醇生产中仅使用一种微生物从木质纤维素生物质生产生物乙醇是可能的。不同农业废弃物也记录到了高沼气/生物甲烷产量，特别是在共消化系统中。据报道，预处理、解毒、微生物共培养的应用、共底物混合比例、有机负荷率、水力停留时间等会影响从农业废弃物生产的不同生物燃料的数量和质量。有趣的是，这些农业废弃物底物在发酵和/或消化过程中被大量降解，以实现高水平的生物修复。因此，本研究全面综述了用作生物燃料底物的各种农业废弃物、实现最佳生物燃料生产的条件以及生物燃料生产过程中底物同时进行生物修复的案例。还恰当介绍了将生物燃料副产品转化为其他重要产品以实现零废物和循环生物经济的情况。
