Effects of cultivation conditions on cell growth and lipid productivity of microalgae Isochrysis zhanjiangensis
DONG Xuewei1, LI Youzhi1, HE Qingfang2,3, YU Jinhui2, BI Yuping2*
1(College of Life Science and Technology, State Key Laboratory for Conservation and Utilization of Subtropical Agro- bioresources, Guangxi University, Nanning 530004, China) 2(Biotechnology Research Center, Shandong Academy of Agricultural Science, Key Laboratory for Genetic Improvement of Crop, Animal and Poultry of Shandong Province, Key Laboratory of Crop Genetic Improvement and Biotechnology, Huanghuaihai, Ministry of Agriculture, Jinan 250100, China) 3(Department of Applied Science, University of Arkansas, 72204, US)
Abstract: In order to improve the microalgae lipid productivity and optimize its cultivation conditions, Isochrysis zhanjiangensis was used as the research object, effects of trophic modes, light intensity, and NaNO3 concentration on the growth and lipid accumulation, as well as the relationship between nitrogen consumption and growth in the course of culture were explored. The results showed that microalgae consumed more nitrogen while it grew faster. Compared to photoautotrophic and photoheterotrophic cultivation, more nitrogen was consumed to meet the growth needs under mixotrophic cultivation condition. More protein were accumulated under the conditions of sufficient nitrogen and mixotrophic cultivation, whereas more oil accumulated under the conditions of low nitrogen concentration and light intensity. Although the highest oil content of 46% was obtained under the photoheterotrophic cultivation when the light intensity was 100 μmol/(m2·s) and NaNO3 concentration was 75 mg/L, the biomass concentration was only 0.46 g/L under the same condition. The highest biomass concentration of 2.20 g/L was obtained under the mixotrophic cultivation when the light intensity was 100 μmol/(m2·s) and NaNO3 concentration was 750 mg/L. However, the oil content was only 32.77%. Considering factors, such as lipid productivity and cost-saving, the best lipid productivity of 80.06 mg/(L·d) was obtained under the mixotrophic cultivation when the light intensity was 100 μmol/(m2·s) and NaNO3 concentration was 375 mg/L. Moreover, polyunsaturated fatty acids accounted for 30.82% of the total fatty acids contents under this condition. Therefore, this is a suitable condition for I. zhanjiangensis to produce microalgae oil as a nutritional substitute.
 RENUKA N, GULDHE A, PRASANNA R, et al. Microalgae as multi-functional options in modern agriculture: current trends, prospects and challenges [J]. Biotechnology Advances, 2018,S0734-9750(18):30076-4.  张方,熊绍专,何加龙,等. 用于生物柴油生产的微藻培养技术研究进展[J]. 化学与生物工程, 2018, 35(1): 5-11.  CHEIRSILP B, TORPEE S. Enhanced growth and lipid production of microalgae under mixotrophic culture condition: effect of light intensity, glucose concentration and fed-batch cultivation [J]. Bioresource Technology, 2012, 110(2): 510-516.  董联,袁振宏,王忠铭,等. 光强与氮源对绿球藻GN38生长和油脂积累的影响[J]. 可再生能源, 2014, 32(1):73-80.  HO SH, YE X, HASUNUMA T, et al. Perspectives on engineering strategies for improving biofuel production from microalgae-a critical review [J]. Biotechnology Advances, 2014, 32(8):1 448-1 459.  GRIFFITHS MJ, HARRISON STL. Lipid productivity as a key characteristic for choosing algal species for biodiesel production [J]. Journal of Applied Phycology, 2009, 21(5):493-507.  GUILLARD RRL, RYTHER JH. Studies of marine planktonic diatoms I. cyclotella nanai hustedt and detonula confervacea cleve[J]. Canadian Journal of Microbiology, 1975, 8(2): 229-239.  BLIGH E, DYER W. A rapid method of total lipid extraction and purification [J]. Canadian Journal of Biochemistry and Physiology, 1959, 37(8): 911-917.  DUBOIS M, GILLED KA, HAMILTON JK, et al. Colorimetric method for determination of sugars and related substances [J]. Analytical Chemistry, 1956, 28(3): 350-356.  BRADFORD MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding [J]. Analytical Biochemistry, 1976, 72(1): 248-254.  DONG XW, HE QF, PENG ZY, et al. Production of γ-linolenic acid and stearidonic acid by Synechococcus sp. PCC7002 containing cyanobacterial fatty acid desaturase genes [J]. Chinese Journal of Oceanology and Limnology, 2016, 34(4):772-780.  COLLOS Y, MORNET F, SCIANDRA A, et al. An optical method for the rapid measurement of micromolar concentrations of nitrate in marine phytoplankton cultures [J]. Journal of Applied Phycology, 1999, 11(2):179-184.  FENG D, CHEN Z, XUE S, et al. Increased lipid production of the marine oleaginous microalgae Isochrysis zhangjiangensis (Chrysophyta) by nitrogen supplement [J]. Bioresource Technology, 2011, 102(12): 6 710-6 716.  LI T, ZHENG Y, YU L, et al. Mixotrophic cultivation of a Chlorella sorokiniana strain for enhanced biomass and lipid production [J]. Biomass & Bioenergy, 2014, 66(3):204-213.  MARTINEZ ME, CAMACHO F, JIMENEZ JM, et al. Influence of light intensity on the kinetic and yield parameters of Chlorella pyrenoidosa mixotrophic growth [J]. Process Biochemistry, 1997, 32(3):93-98.  LI T, GARGOURI M, FENG J, et al. Regulation of starch and lipid accumulation in a microalga Chlorella sorokiniana [J]. Bioresource Technology, 2015, 180(3):250-257.  KRZEMINSKA I, PAWLIK-SKOWRONSKA B, TRZCINSKA M, et al. Influence of photoperiods on the growth rate and biomass productivity of green microalgae [J]. Bioprocess Biosystems Engineering, 2014, 37(4):735-741.  RODOLFI L, CHINI ZITTELLI G, BASSI N, et al. Microalgae for oil: strain selection, induction of lipid synthesis and outdoor mass cultivation in a low-cost photobioreactor [J]. Biotechnology and Bioengineering, 2009, 102(1): 100-112.  LV JM, CHENG LH, XU XH. Enhanced lipid production of Chlorella vulgaris by adjustment of cultivation conditions [J]. Bioresource Technology, 2010, 101(17): 6 797-6 804.  JUNTILA DJ, BAUTISTA MA, MONOTILLA W. Biomass and lipid production of a local isolate Chlorella sorokiniana under mixotrophic growth conditions [J]. Bioresource Technology, 2015, 191(3):395-398.  GOODSON C, ROTH R, WANG ZT, et al. Structural correlates of cytoplasmic and chloroplast lipid body synthesis in acetate boost [J]. Eukaryotic Cell, 2011, 10(12):1 592-1 606.  MANDAL S, MALLICK N. Microalga Scenedesmus obliquus as a potential source for biodiesel production [J]. Applied Microbiology and Biotechnology, 2009, 84(2):281-291.  JOHNSON X, ALRIC J. Central carbon metabolism and electron transport in Chlamydomonas reinhardtii: metabolic constraints for carbon partitioning between oil and starch [J]. Eukaryotic Cell, 2013, 12(6):776-793.  WASE N, BLACK PN, STANLEY BA, et al. Integrated quantitative analysis of nitrogen stress response in Chlamydomonas reinhardtii using metabolite and protein profiling [J]. Journal of Proteome Reseach, 2014, 13(3):1 373-1 396.  GUEDES AC, MEIRELES LA, AMARO HM, et al. Changes in lipid class and fatty acid composition of cultures of Pavlova lutheri, in response to light intensity [J]. Journal of the American Oil Chemistry Society, 2010, 87(7): 791-801.  CHRISMADHA, BOROWITZKA MA. Effect of cell density and irradiance on growth, proximate composition and eicosapentaenoic acid production of Phaeodactylum tricornutum grown in a tubular photobioreactor [J]. Journal of Applied Phycology, 1994, 6(1): 67-74.  HO SH, NAKANISHI A, YE X, et al. Dynamic metabolic profiling of the marine microalga Chlamydomonas sp. Jsc4 and enhancing its oil production by optimizing light intensity [J]. Biotechnology for Biofuels, 2015, 8(1): 48.  印尤强,黄罗东,胡强,等. 光强和氮源及其浓度对缺刻缘绿藻生长、油脂和花生四烯酸积累的影响[J]. 植物科学学报, 2017, 35(4):592-602.  SHIN YS, CHOI HI, CHOI JW, et al. Multilateral approach on enhancing economic viability of lipid production from microalgae: A review [J]. Bioresource Technology, 2018, 258(5):335-344.  PARK J, SEO J, KWON EE. Microalgae production using wastewater: effect of light-emitting diode wavelength on microalgal growth [J]. Environmental Engineering Science, 2012, 29(11):995-1 001.  GONCALVES AL, SIMOES M, PIRES JCM. The effect of light supply on microalgal growth, CO2 uptake and nutrient removal from wastewater [J]. Energy Conversion and Management, 2014, 85(4):530-536.  PINCHETTI JLG, FERNANDEZ EC, DIEZ PM. Nitrogen availability influences the biochemical composition and photosynthesis of tank-cultivated Ulva rigida (Chlorophyta) [J]. Journal of Applied Phycology, 1998, 10(3): 383-389.  SCHENK PM, THOMAS-HALL SR, STEPHENS E, et al. Second generation biofuels: high-efficiency microalgae for biodiesel production [J]. Bioenergy Research, 2008, 1(1): 20-43.