Conventionally, production of methyl ester fuels from microalgae occurs through an energy-intensive two-step chemical extraction and transesterification process. To improve the energy efficiency, we performed in situ enzymatic conversion of whole algae biomass from an oleaginous heterokont microalga Nannochloropsis oceanica IMET1 with the immobilized lipase from Candida antarctica. The fatty acid methyl ester yield reached 107.7% for dry Nannochloropsis biomass at biomass to t-butanol to methanol weight ratio of 1:2:0.5 and a reaction time of 12 h at 25 °C, representing the first report of efficient whole algae biomass conversion into fatty acid methyl esters at room temperature. Different forms of algal biomass including wet Nannochloropsis biomass were tested. The maximum yield of wet biomass was 81.5%. Enzyme activity remained higher than 95% after 55 days of treatment (equal to 110 cycles of reaction) under the conditions optimized for dry algae biomass conversion. The low reaction temperature, high enzyme stability, and high yield from this study indicate in situ enzymatic conversion of dry algae biomass may potentially be used as an energy-efficient method for algal methyl ester fuel production while allowing co-product recovery.

中文翻译：

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Nannochloropsis oceanica IMET1生物质的原位酶转化为脂肪酸甲基酯。

常规地，由微藻类生产甲酯燃料是通过能量密集的两步化学提取和酯交换过程进行的。为了提高能源效率，我们用固定化的南极假丝酵母脂肪酶对油性异种微藻Nannochloropsis oceanica IMET1的整个藻类生物质进行了原位酶转化。在生物量与叔丁醇与甲醇的重量比为1：2：0.5且在25°C下反应时间为12 h的条件下，干燥的拟南芥生物量的脂肪酸甲酯产率达到107.7％，这是首次报道了有效的全藻生物量在室温下转化为脂肪酸甲酯。不同形式的藻类生物质，包括湿的测试了拟南芥生物量。湿生物质的最大产率为81.5％。在优化干藻生物质转化的条件下，经过55天的处理（相当于110个反应周期），酶活性保持高于95％。该研究的低反应温度，高酶稳定性和高收率表明，干藻生物质的原位酶转化可潜在地用作藻类甲酯燃料生产的节能方法，同时允许副产物回收。