Botany and Microbiology Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
School of Food & Biological Engineering, Jiangsu University, Zhenjiang, 212013, China.
Environ Sci Pollut Res Int. 2020 Sep;27(26):32481-32493. doi: 10.1007/s11356-020-09534-1. Epub 2020 Jun 6.
The present study evaluated the sequential biodiesel-bioethanol production from seaweeds. A total of 22 macroalgal species were collected at different seasons and screened based on lipid and carbohydrate contents as well as biomass production. The promising species was selected, based on the relative increase in energy compounds (REEC, %), for further energy conversion. Seasonal and annual biomass yields of the studied species showed significant variations. The rhodophyte Amphiroa compressa and the chlorophyte Ulva intestinalis showed the highest annual biomass yield of 75.2 and 61.5 g m year, respectively. However, the highest annual carbohydrate productivity (ACP) and annual lipid productivity (ALP) were recorded for Ulva fasciata and Ulva intestinalis (17.0 and 3.0 g m year, respectively). The later was selected for further studies because it showed 14.8% higher REEC value than Ulva fasciata. Saturated fatty acids (SAFs) showed 73.4%, with palmitic acid as a dominant fatty acid (43.8%). Therefore, biodiesel showed high saturation degree, with average degree of unsaturation (ADU) of 0.508. All the measured biodiesel characteristics complied the international standards. The first route of biodiesel production (R1) from Ulva intestinalis showed biodiesel recovery of 32.3 mg g dw. The hydrolysate obtained after saccharification of the whole biomass (R2) and lipid-free biomass (R3) contained 1.22 and 1.15 g L, respectively, reducing sugars. However, bioethanol yield from R3 was 0.081 g g dw, which represented 14.1% higher than that of R2. Therefore, application of sequential biofuel production using R3 resulted in gross energy output of 3.44 GJ ton dw, which was 170.9% and 82.0% higher than R1 and R2, respectively. The present study recommended the naturally-grown Ulva intestinalis as a potential feedstock for enhanced energy recovery through sequential biodiesel-bioethanol production.
本研究评估了海藻的生物柴油-生物乙醇连续生产。在不同季节采集了总共 22 种大型藻类，并根据脂质和碳水化合物含量以及生物量生产进行了筛选。根据能源化合物（REEC，%）的相对增加，选择有前途的物种进行进一步的能量转化。所研究物种的季节性和年度生物量产量存在显著差异。红藻 Amphiroa compressa 和绿藻 Ulva intestinalis 的年生物量产量最高，分别为 75.2 和 61.5 g m year。然而，Ulva fasciata 和 Ulva intestinalis 的年碳水化合物生产力（ACP）和年脂质生产力（ALP）最高，分别为 17.0 和 3.0 g m year。由于 Ulva intestinalis 的 REEC 值比 Ulva fasciata 高 14.8%，因此选择后者进行进一步研究。饱和脂肪酸（SAFs）的含量为 73.4%，其中棕榈酸是主要脂肪酸（43.8%）。因此，生物柴油的饱和度高，平均不饱和度（ADU）为 0.508。所有测量的生物柴油特性均符合国际标准。从 Ulva intestinalis 生产生物柴油的第一种途径（R1）显示生物柴油的回收率为 32.3 mg g dw。全生物质（R2）和无脂生物质（R3）糖化后获得的水解物分别含有 1.22 和 1.15 g L 的还原糖。然而，R3 的生物乙醇得率为 0.081 g g dw，比 R2 高 14.1%。因此，通过 R3 进行连续生物燃料生产的应用可产生 3.44 GJ ton dw 的总能量输出，分别比 R1 和 R2 高 170.9%和 82.0%。本研究建议将自然生长的 Ulva intestinalis 作为一种潜在的原料，通过连续生产生物柴油-生物乙醇来提高能源回收。
