Biofuels, produced from organic materials such as plants, animal waste, and wood chips etc. offer a sustainable and renewable alternative to fossil fuels. The biofuel production in terms of thousand barrels of oil equivalent per day was 1914.00 in 2022 worldwide. The demand is set to expand 38 billion liters over 2023–28, nearly 30 per cent increase in the last five years with bioethanol & biodiesel accounting for about two third share. First-generation biofuels are derived from food crops, while second-generation biofuels are made from non-food crops like switchgrass, algae, and agricultural waste. Microbe-derived biofuels are ecologically sound on account of fewer greenhouse gas emissions and are more sustainable than conventional fossil fuels. However, there are challenges associated with producing biofuels, including land use competition, feedstock cost and availability, technical limitations, sustainability issues, and infrastructure and market constraints. Second-generation biofuels and third-generation algae-based biofuels have the potential to condense our dependence on fossil fuels and reassure sustainable agriculture and forestry practices. Fourth-generation biofuels use genetically modified microorganisms to convert sunlight and CO into biofuels directly while as fifth-generation biofuels are still in the research and development stage and are expected to use synthetic biology to create completely synthetic biofuels. Advanced biofuels from non-food feedstocks like algae, agricultural byproducts, and municipal solid waste are ecologically more well-founded than first-generation biofuels. Biorefinery mediated biomass conversion to biofuels is more energy efficient more productive and ecologically all-encompassing than conventional refineries. Synthetic biology approaches such as genetic engineering, directed evolution, genome editing is used to expand the thruput and efficiency of microorganisms in the production course of biofuels. Overall, the production of biofuels from microorganisms has the potential to be an economically and environmentally sustainable method of generating renewable energy. With continued innovation and emphasis on sustainability, microbe-derived biofuels could become a substantial part of the evolution towards a more renewable and sustainable energy future. The concerns as a result of climate change have dictated a rethink in policy pertaining to transportation infrastructure. One possible alternative to existing setup of fossil fuels is the biofuels produced as result of efficient microflora that make the use of renewable carbon stocks. Advanced biofuels that could mimic the petroleum-based fuels pose a limited scope on account of the challenging costs. The computational biology in context to synthetic enzyme production could amplify the production process beyond doubt. In this review, we discuss the new insights into challenges and opportunities of the generation wise biofuels besides the advancements made in microflora in various biofuel generations.

中文翻译：

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生物燃料世代：对微生物衍生工业生产中的挑战和机遇的新见解

由植物、动物粪便和木片等有机材料生产的生物燃料为化石燃料提供了可持续和可再生的替代品。 2022 年，全球生物燃料产量（以千桶油当量/日计）为 1914.00 桶油当量。 2023-28 年需求预计将增加 380 亿升，过去五年增长近 30%，其中生物乙醇和生物柴油约占三分之二份额。第一代生物燃料来自粮食作物，而第二代生物燃料则由柳枝稷、藻类和农业废物等非粮食作物制成。微生物衍生的生物燃料由于温室气体排放较少而对生态无害，并且比传统化石燃料更可持续。然而，生产生物燃料也存在一些挑战，包括土地使用竞争、原料成本和可用性、技术限制、可持续性问题以及基础设施和市场限制。第二代生物燃料和第三代藻类生物燃料有可能减少我们对化石燃料的依赖，并确保可持续农业和林业实践。第四代生物燃料利用转基因微生物将阳光和二氧化碳直接转化为生物燃料，而第五代生物燃料仍处于研发阶段，预计将利用合成生物学来制造完全合成的生物燃料。来自藻类、农业副产品和城市固体废物等非食品原料的先进生物燃料在生态上比第一代生物燃料更有基础。与传统炼油厂相比，生物精炼厂介导的生物质转化为生物燃料的能源效率更高、生产力更高、生态更全面。基因工程、定向进化、基因组编辑等合成生物学方法用于扩大生物燃料生产过程中微生物的产量和效率。总体而言，利用微生物生产生物燃料有可能成为一种经济和环境可持续的生产可再生能源的方法。随着不断的创新和对可持续性的重视，微生物衍生的生物燃料可能成为朝着更加可再生和可持续的能源未来发展的重要组成部分。对气候变化的担忧促使人们重新思考与交通基础设施相关的政策。现有化石燃料设置的一种可能替代方案是利用可再生碳库的高效微生物群落生产的生物燃料。由于成本具有挑战性，可以模仿石油基燃料的先进生物燃料的范围有限。毫无疑问，与合成酶生产相关的计算生物学可以放大生产过程。在这篇评论中，除了各代生物燃料在微生物区系方面取得的进步之外，我们还讨论了对各代生物燃料的挑战和机遇的新见解。