Application Of Sunlight-Conversion Film On The Aquiculture Of Microalgae

As a main contributor of the global primary producer, microalgae are becoming one of the most important sources of food, medicines and chemical materials in the21st century. Low photosynthetic efficiency and low light utilization rate has restricted production scale and commercial use. It was reported that Sunlight-Conversion Film (SCF), which was usually used in agriculture, could make light quality conversion and improve light utilization rate. The aim of this study was tried to apply SCF into the aquiculture of algae and enhance photosynthetic capacity through light quality changes.In this work, the influence of light quality on cell growth, product accumulation and photosynthesis activity of microalgae was studied, Sunlight-Conversion Agent (SCA) was chosen and SCF was prepared, then the feasibility of taking SCF into the aquiculture of Haematococcus pluvialis and Spirulina platensis was investigated. The main results are as follows:The influence of light quality on the growth of H. pluvialis and S. platensis was obviously. The cell growth, pigments accumulation and photosynthesis were accelerated by red light, which were called "Red-light respond". The biomass, chlorophyll and astaxanthin of H. pluvialis were improved by9.6%,18.9%and16.9%higher than that of the control experiment respectively; As for S. platensis, the biomass and chlorophyll a were higher than those of the comparison by28%and27.4%respectively. Blue light and green light had no contribution to biomass and pigments accumulation. But the blue is beneficial for protein synthesis. The protein of S. platensis in blue light was about10.47percentage points higher than that in white light. The SCA was chosen to make the films, which convert violet and green light into red light. The results of the fluorescence test showed that SCF could strengthen the intensity mainly in red light range (630nm-680nm) and a little in blue light range.In order to study the effect of SCF on the growth, pigment accumulation and photosynthesis of alga, S. platensis and H. pluvialis were cultured in flask and air-lift bioreactor indoors and outdoors. The results showed that SCF was helpful for both of them. The final biomass, chlorophyll and astaxanthin of H. pluvialis in air-lift bioreactor covered by SCF indoors were increased by8.8%,11.45%and10.27%respectively. While the biomass and chlorophyll a of S. platensis under the same conditions was increased by6.7%and8.4%respectively and the protein improved by3.65percentage points. The biomass and pigment concentration obtained outdoors were higher than those indoors. The photosynthesis activity determinations showed that the net maximum photosynthetic rate and initial slope were both higher with SCF than PE film. That is, the SCF promoted the photosynthesis of alga. Cost analysis showed that the SCF could bring up economy benefit notablely.