Carbon dioxide gas is the key element of the carbon cycle and a major source for photosynthesis, but for the past 150 years, the atmospheric CO₂ has been increased drastically from 250 to 418 ppm due to the extreme utilization of fossil fuels. This accelerated release of CO₂ acts as a major source for climatic change due to the greenhouse gas effect resulting in global warming and melting of polar ice caps, alteration in biogeochemical cycles, altered rainfall, ocean acidification, eutrophication of lakes, imbalance in the ecological communities and extinction of some species, effects on soil fertility, changes in the metabolism and at the molecular level. Reduce, reuse and recycle strategy can be applied to control elevated CO₂ levels by preventing deforestation, using renewable energy as an alternative for fossil fuels and reusing the atmospheric CO₂. Carbon capture and storage (CCS), Carbon capture and utilization (CCU) are the two technologies adapted to capture the atmospheric CO₂, utilize it, and focus on permanent storage in the geological sites. Captured CO₂ is used to produce many value added products such as polymers, biofuels, reactants etc. Plants and microorganisms act as a natural CO₂ filter. Several biomolecules such as carbohydrates, proteins, and lipids are produced due to the biological carbon fixation process using photosynthesis. Six different photosynthetic pathways and some non-photosynthetic pathways to fix atmospheric CO₂ have been reported in diverse species of plants and microbes such as bacteria, fungi, yeast, algae etc. Algae are the most potent microbe in CO₂ utilization and biological carbon fixation compared to other microbes and used widely on a large industrial scale for biofuel production. Algal biofuel production using captured CO₂ is the best productive method to recycle and reduce atmospheric CO₂.

二氧化碳气体是碳循环的关键元素，并且是光合作用的主要来源，但是在过去的150年中，由于对化石燃料的过度利用，大气中的CO ₂急剧增加，从250 ppm增加到418 ppm。由于温室气体的作用，导致全球变暖和极地冰盖融化，生物地球化学循环改变，降雨改变，海洋酸化，湖泊富营养化，生态失衡，导致温室气体效应，CO _2的这种加速释放成为气候变化的主要来源。群落和某些物种的灭绝，对土壤肥力的影响，新陈代谢的变化以及分子水平的变化。减少，再利用和再循环策略可用于控制升高的CO ₂通过防止森林砍伐，使用可再生能源作为化石燃料的替代品并重新利用大气中的CO _2来降低排放水平。碳捕集与封存（CCS），碳捕集与利用（CCU）是两种适用于捕获大气中CO ₂，加以利用并专注于地质地点永久性存储的技术。捕获的CO ₂用于生产许多增值产品，例如聚合物，生物燃料，反应物等。植物和微生物充当天然CO ₂过滤器。由于使用光合作用的生物碳固定过程，产生了几种生物分子，例如碳水化合物，蛋白质和脂质。六种不同的光合途径和一些非光合途径固定大气中的CO在各种植物和微生物中，例如细菌，真菌，酵母，藻类等，已报道了₂种。与其他微生物相比，藻类是CO ₂利用和生物固碳能力最强的微生物，在工业规模上广泛用于生物燃料生产。使用捕获的CO ₂生产藻类生物燃料是回收和减少大气中CO ₂的最佳生产方法。