光照强度对原位藻细胞组分生长及生物柴油性能的影响

Effects of light intensity on growth of native microalgal cellular components and performance of biodiesel

为了探究光强对污水原位藻生长、光合活性及藻细胞胞内/外组分的影响,对比研究了2个光强(54μmol/(m^(2)·s)、1000μmol/(m^(2)·s))下原位藻细胞数、藻液pH、叶绿素含量及光合作用参数(F_(v)/F_(m)、rETR)的变化,以及胞外聚合物、胞内蛋白质、多糖和脂肪酸含量等原位藻细胞内/外组分的响应特性。结果表明:与低光强相比,高光强下原位藻生物量下降47.63%,藻液pH由6.60快速提升至11.36,叶绿素浓度仅为1.66 mg/L,光合活性下降,生长被显著抑制;胞内蛋白质和多糖含量分别下降29.19%和16.23%,而胞外聚合物含量显著提高58.14%;脂肪酸含量上升(440.548 mg/L)且成分比例发生变化,高光强下培养的原位藻生物柴油具有较好的氧化稳定性能、亲水性能、燃烧性能、高温保护性能,而低温流动性及能量则略逊于低光强组。

To investigate the effects of light intensity on the growth,photosynthetic activity and intracellular/extracellular components of native microalgae from wastewater,this paper comparatively investigated the effects of different light intensities(i.e.groups with low light intensity of 54μmol/(m^(2)·s)and high light intensity of 1000μmol/(m^(2)·s))on the growth and photosynthetic activity of native microalgae by measuring the variations on cell numbers,pH,chlorophyll content and photosynthetic parameters(F_(v)/F_(m),rETR),as well as the response characteristics of native microalgal intracellular and extracellular components such as extracellular polymeric substances,intracellular proteins,polysaccharides and fatty acid content.The results demonstrated that compared with the low light intensity group,the biomass was reduced by 47.63%under high light intensity and the pH increased rapidly from 6.60 to 11.36.The chlorophyll concentration was only 1.66 mg/L and the photosynthetic activity of native microalgae was remarkably decreased,which might contribute to the inhibited growth of microalgae.Under the high light intensity,the intracellular protein and polysaccharide content decreased by 29.19%and 16.23%respectively,while the extracellular polymer content significantly increased by 58.14%.Moreover,the fatty acid content increased(440.548 mg/L)with variations on the composition ratio,and the high light intensity group also presented better oxidative stability,hydrophilicity,combustion performance and high temperature protection performance,in spite of the slightly low temperature fluidity and energy.