Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India.
Biotechnology Division, Aban Infrastructure Pvt Ltd, Janpriya Crest, 113, Pantheon Road, Egmore, Chennai, 600 008, India.
BMC Microbiol. 2018 Jan 3;18(1):1. doi: 10.1186/s12866-017-1144-x.
Renewable energy for sustainable development is a subject of a worldwide debate since continuous utilization of non-renewable energy sources has a drastic impact on the environment and economy; a search for alternative energy resources is indispensable. Microalgae are promising and potential alternate energy resources for biodiesel production. Thus, our efforts were focused on surveying the natural diversity of microalgae for the production of biodiesel. The present study aimed at identification, isolation, and characterization of oleaginous microalgae from shola forests of Nilgiri Biosphere Reserve (NBR), the biodiversity hot spot of India, where the microalgal diversity has not yet been systematically investigated.
Overall the higher biomass yield, higher lipid accumulation and thermotolerance observed in the isolated microalgal strains have been found to be the desirable traits for the efficient biodiesel production. Species composition and diversity analysis yielded ten potential microalgal isolates belonging to Chlorophyceae and Cyanophyceae classes. The chlorophytes exhibited higher growth rate, maximum biomass yield, and higher lipid accumulation than Cyanophyceae. Among the chlorophytes, the best performing strains were identified and represented by Acutodesmus dissociatus (TGA1), Chlorella sp. (TGA2), Chlamydomonadales sp. (TGA3) and Hindakia tetrachotoma (PGA1). The Chlamydomonadales sp. recorded with the highest growth rate, lipid accumulation and biomass yield of 0.28 ± 0.03 day (μ), 29.7 ± 0.69% and 134.17 ± 16.87 mg L day, respectively. It was also found to grow well at various temperatures, viz., 25 °C, 35 °C, and 45 °C, indicating its suitability for open pond cultivation. The fatty acid methyl ester (FAME) analysis of stationary phase cultures of selected four algal strains by tandem mass spectrograph showed C16:0, C18:1 and C18:3 as dominant fatty acids suitable for biodiesel production. All the three strains except for Hindakia tetrachotoma (PGA1) recorded higher carbohydrate content and were considered as potential feed stocks for biodiesel production through hydrothermal liquefaction technology (HTL).
In conclusion, the present investigation is a first systematic study on the microalgal diversity of soil and water samples from selected sites of NBR. The study resulted in isolation and characterization of ten potent oleaginous microalgae and found four cultures as promising feed stocks for biodiesel production. Of the four microalgae, Chlamydomonadales sp. (TGA3) was found to be significantly thermo-tolerant and can be considered as promising feedstock for biodiesel production.
可再生能源可持续发展是一个全球性的辩论主题，因为不可再生能源的持续利用对环境和经济有巨大的影响；寻找替代能源资源是必不可少的。微藻是生产生物柴油有前途和潜在的替代能源。因此，我们的努力集中在调查微藻的自然多样性，以生产生物柴油。本研究旨在鉴定、分离和表征来自印度生物多样性热点尼尔吉里生物圈保护区（NBR）的土壤和水样中的产油微藻，该地区的微藻多样性尚未得到系统调查。
总体而言，在分离的微藻菌株中观察到的更高的生物量产量、更高的脂质积累和耐热性被认为是有效生产生物柴油的理想特性。物种组成和多样性分析得到了 10 种潜在的微藻分离株，属于绿藻门和蓝藻门。绿藻的生长速度、最大生物量产量和脂质积累均高于蓝藻。在绿藻中，表现最好的菌株被鉴定为Acutodesmus dissociatus（TGA1）、Chlorella sp.（TGA2）、Chlamydomonadales sp.（TGA3）和Hindakia tetrachotoma（PGA1）。Chlamydomonadales sp.记录了最高的生长速度、脂质积累和生物量产量，分别为 0.28±0.03 天（μ）、29.7±0.69%和 134.17±16.87mg L 天。它还被发现能在各种温度下生长良好，即 25°C、35°C 和 45°C，表明它适合于开放池塘培养。通过串联质谱仪对选定的 4 株藻类的静止期培养物进行脂肪酸甲酯（FAME）分析，结果表明 C16:0、C18:1 和 C18:3 是适合生产生物柴油的主要脂肪酸。除 Hindakia tetrachotoma（PGA1）外，所有 3 株菌株的碳水化合物含量均较高，被认为是通过水热液化技术（HTL）生产生物柴油的潜在原料。
总之，本研究是对 NBR 选定地点的土壤和水样中微藻多样性的首次系统研究。研究结果分离和鉴定了 10 种有潜力的产油微藻，并发现 4 种培养物是生产生物柴油的有前途的原料。在这 4 种微藻中，Chlamydomonadales sp.（TGA3）被发现具有显著的耐热性，可作为生产生物柴油的有前途的原料。
