Mubarak M, Shaija A, Suchithra T V
Mechanical Engineering Department, National Institute of Technology Calicut, Kerala, India.
School of Biotechnology, National Institute of Technology Calicut, Kerala, India.
Environ Sci Pollut Res Int. 2016 Jul;23(14):14047-55. doi: 10.1007/s11356-016-6343-8. Epub 2016 Apr 5.
The higher areal productivity and lipid content of microalgae and aquatic weed makes them the best alternative feedstocks for biodiesel production. Hence, an efficient and economic method of extracting lipid or oil from aquatic weed, Salvinia molesta is an important step towards biodiesel production. Since Salvinia molesta is an unexplored feedstock, its total lipid content was first measured as 16 % using Bligh and Dyer's method which was quite sufficient for further investigation. For extracting more amount of lipid from Salvinia molesta, methanol: chloroform in the ratio 2:1 v/v was identified as the most suitable solvent system using Soxhlet apparatus. Based on the literature and the preliminary experimentations, parameters such as solvent to biomass ratio, temperature, and time were identified as significant for lipid extraction. These parameters were then optimized using response surface methodology with central composite design, where experiments were performed using twenty combinations of these extraction parameters with Minitab-17 software. A lipid yield of 92.4 % from Salvinia molesta was obtained with Soxhlet apparatus using methanol and chloroform (2:1 v/v) as solvent system, at the optimized conditions of temperature (85 °C), solvent to biomass ratio (20:1), and time (137 min), whereas a predicted lipid yield of 93.5 % with regression model. Fatty acid methyl ester (FAME) analysis of S. molesta lipid using gas chromatograph mass spectroscopy (GCMS) with flame ionization detector showed that fatty acids such as C16:0, C16:1, C18:1, and C18:2 contributed more than 9 % weight of total fatty acids. FAME consisted of 56.32, 28.08, and 15.59 % weight of monounsaturated, saturated, and polyunsaturated fatty acids, respectively. Higher cetane number and superior oxidation stability of S. molesta FAME could be attributed to its higher monounsaturated content and lower polyunsaturated content as compared to biodiesels produced from C. vulgaris, Sunflower, and Jatropha.
微藻和水草较高的单位面积生产力及脂质含量使其成为生物柴油生产的最佳替代原料。因此，一种从水草槐叶萍中高效且经济地提取脂质或油的方法，是迈向生物柴油生产的重要一步。由于槐叶萍是一种未被开发的原料，其总脂质含量首先使用布莱和戴尔的方法测定为16%，这一含量足以用于进一步研究。为了从槐叶萍中提取更多脂质，使用索氏提取器确定甲醇与氯仿体积比为2:1的混合液是最合适的溶剂体系。基于文献和初步实验，溶剂与生物质的比例、温度和时间等参数被确定为脂质提取的重要因素。然后使用中心复合设计的响应面方法对这些参数进行优化，利用Minitab - 17软件对这些提取参数的20种组合进行实验。在温度（85°C）、溶剂与生物质比例（20:1）和时间（137分钟）的优化条件下，使用索氏提取器以甲醇和氯仿（2:1 v/v）作为溶剂体系，从槐叶萍中获得的脂质产率为92.4%，而回归模型预测的脂质产率为93.5%。使用带有火焰离子化检测器的气相色谱 - 质谱联用仪（GCMS）对槐叶萍脂质进行脂肪酸甲酯（FAME）分析表明，C16:0、C16:1、C18:1和C18:2等脂肪酸占总脂肪酸重量的9%以上。FAME分别由56.32%、28.08%和15.59%重量的单不饱和脂肪酸、饱和脂肪酸和多不饱和脂肪酸组成。与从普通小球藻、向日葵和麻风树生产的生物柴油相比，槐叶萍FAME较高的十六烷值和优异的氧化稳定性可归因于其较高的单不饱和脂肪酸含量和较低的多不饱和脂肪酸含量。
