The Effect of Gibberellic Acid on the Production Characteristics and Biochemical Parameters of Tetraselmis Suecica in an Enrichment Culture
The use of gibberellic acid as a stimulator of microalgae growth has beensubstantiatedexperimentally.This research aimed to assess the effect of exposure to a wide range of gibberellic acid concentrations on the growth dynamics ofthe microalgaTetraselmissuecicain an enrichment culture. The duration of the experiments was 14 days. It has been shown that gibberellic acid,atconcentrations of 0.39–3.20× 10−8M, stimulates algaegrowth. In this research, the exposure to gibberellic acid at concentrations of 0.39–3.20 × 10−8M was accompanied by a variation in the pattern of growth curves: the maximum number of cells was recorded on day seven of the experiment. A higher concentration of the phytohormone (3.84 × 10−8М) inhibited the increase inculture density. The growth of theT. suecicaculture in the control group was 332%;the growth of the culture exposed to gibberellic acid at a concentration of 0.39 × 10−8M was1136%. The values of the specific growth rate ofT. suecicawere estimated for different periods of cultivation. On day14 of the experiment, the biochemical composition of microalgae biomass was analyzed.According to the results, gibberellic acid stimulated the accumulation of carbohydrates, proteins, and chlorophyll. Nevertheless, the phytohormone had no effect on lipidaccumulation. An assumption was made thatexposure to low concentrations of phytohormone stimulates the growth of microalgae by reducing the lag phase of growth.
Keywords: gibberellic acid, microalga, cultivation, lipids, carbohydrates, proteins
 Kabanova YG. On the cultivation of marine plankton diatoms and peridiniales algae in laboratory conditions. Proceedings of the Institute of Oceanology of the Academy of Sciences of the USSR.. 1961;47:203–216.
 Romanenko EA, Kosakovskaya IV, RomanenkoPA. Phytohormones of microalgae: Biological role and involvement in the regulation of physiological processes. Pt I. Auxins, abscisic acid, ethylene.Algologia.2015;25(3):330–351.
 Romanenko EA, Kosakovskaya IV, Romanenko PA.Phytohormones of microalgae: Biological role and involvement in the regulation of physiological processes. Pt II. Cytokinins and gibberellins.Algologia.2016;26(2):203–229.
 TrenkenshuRP. Calculation of the specific growth rate of microalgae.Marine Biolgy Journale 2019;4(1):100–108.
 Aminot A, Ray F. ICES techniques in marine environmental sciences (Iss 30). International Council for the Exploration of the Sea; 2001.Standard procedure for the determination of chlorophyll a by spectroscopic methods. Denmark, Copenhagen, Francisco ReyInstitute of Marine Research
 Bentley-Mowat JA, Reid SM. Effect of gibberellins, kinetin and other factors on the growth of unicellular marine algae in culture.Botanica Marina. 1969;12:185—199.
 Camacho-Rodríguez J, González-Céspedes AM, Cerón-García MC, FernándezSevilla JM, Acién-Fernández FG, Molina-Grima EA. A quantitative study of eicosapentaenoic acid (EPA) production by Nannochloropsisgaditana for aquaculture as a function of dilution rate, temperature and average irradiance.Applied Microbiolgy Biotechnolgy 2014;98:2429–2440.
 ?arneiro M, Pojo V, Malcata FX, Otero A. Lipid accumulation in selected Tetraselmis strains. Journal of Applied Phycology. 2019;31:2845–2853.
 Chauton MS, Reitan KI, Norsker NH, Tveterås R, Kleivdal HTA. A techno-economic analysis of industrial production of marine microalgae as a source of EPA and DHA-rich raw material for aquafeed: Research challenges and possibilities. Aquaculture.2015;436:95–103.
 Conceição LEC, Yúfera M, Makridis P, Morais S, Dinis MT. Live feeds for early stages of fish rearing. Aquaculture Research. 2010;41:613–640.
 Christie W.W. Lipid analysis: Isolation, identification and structural analysis of lipids.Bridgwater: The Oily Press; 2003.
 Evans WK, Sorokin C. Studies of the effect of gibberellic acid on algal growth.Life Science 1971;10:1227—1235.
 Johnston R. Effects of gibberellin on marine algae in mixed cultures. Limnology and Oceanography.1963;8(2): 270—275.
 Herbert D, Phipps PJ, Strange RE. Chemical analysis of microbial cells. Journal of Microbiological Methods1971;58:209-344.
 Laurens LML, Dempster TA, Jones HDT et al. Algal biomass constituent analysis: Method uncertainties and investigation of the underlying measuring chemistries. Analytical Chemistry. 2012;84(4):1879–1887.
 Lowry O, Rosenbrougt N, Parr A, Randall R. Protein measurement with the folin phenol reagent. Journal of Biological Chemistry. 1951;193(1):265–276.
 Mowat JA. A survey of results on the occurrence of auxins and gibberellins in algae.Botanica Marina 1965;8(1):149—155.
 Pan X, Chang F, Kang L, Liu Y, Li G, Li D. Effects of gibberellin A3 on growth and microcystin production in Microcystis aeruginosa (Cyanophyta). Journal of Plant Physiology.2008;165:1691—1697.
 Park W, Yoo G, Moon M, Kim CW, Choi Y, Yang J. Phytohormone supplementation significantly increases growth of Chlamydomonas reinhardtii cultivated for biodiesel production.Applied Biochemistry and Biotechnology 2013;171:1128—1142.
 Stirk WA, Bálint P, Tarkowská D, Novák O, Strnad M, Ördög V, van Staden J. Hormone profiles in microalgae: Gibberellins and brassinosteroids. Plant Physiology and Biochemistry. 2013;70:348—353.