Algae and their Biotechnological Potential: Proceedings of the 4th Asia-Pacific Conference on Algal Biotechnology, 3–6 July 2000 in Hong Kong PDF
Preview Algae and their Biotechnological Potential: Proceedings of the 4th Asia-Pacific Conference on Algal Biotechnology, 3–6 July 2000 in Hong Kong
ALGAE AND THEIR BIOTECHNOLOGICAL POTENTIAL ALGAE AND THEIR BIOTECHNOLOGICAL POTENTIAL Proceedings of the 4th Asia-Pacific Conference on Algal Biotechnology, 3-6 July 2000 in Hong Kong Editedby Feng Chen DepartmentofBotany. TheUniversity ofHong Kong and YueJiang DepartmentofBotany, The University ofHong Kong .... " Springer-Science+Business Media, B.Y. AC.I.P.Cataloguerecordforthisbook isavailablefrom theLibrary ofCongress. ISBN978-90-481-5886-7 ISBN978-94-015-9835-4(eBook) DOI10.1007/978-94-015-9835-4 Printed onacid-freepaper AllRights Reserved ©2001SpringerScience+BusinessMediaDordrecht OriginallypublishedbyKluwerAcademicPublishersin2001. Softcoverreprintofthehardcover Istedition200I Nopartofthematerial protected bythiscopyright notice maybereproducedor utilized inanyform orbyanymeans, electronic ormechanical, including photocopying, recording orbyanyinformation storageand retrievalsystem, without writtenpermission from thecopyright owner. Contents Preface ix 1 Polyunsaturated FattyAcids: Biological Significance, Biosynthesis,and 1 Production by Microalgaeand Microalgae-likeOrganisms c:s. Yap andF.Chen 2 Application ofStatistically-Based ExperimentalDesigns for Optimizing 33 EicosapentaenoicAcid Production byNitzschia /aevis Z.Y. Wenand F.Chen 3 Optimization ofNitrogen Sources for theProduction ofEicosapentaenoic 55 Acid by the Diatom Nitzschia /aevisinHeterotrophicCultures Z.Y. WenandF.Chen 4 Effects of Nitrogen Sourceand Vitamin B on DocosahexaenoicAcid 69 12 Production byCrypthecodiniumcohnii Y.Jiang,F.Chen andH.S. Li 5 Neural Networks for Modellingand Predictingthe Ch/orellaprotothecoides 79 Cultivation Processes G.Y.Zhang,S.Y.Guo, L. Li,W.S. Zhou andM.Y.Cai 6 Modellingofa Continuous Algal Production System Using Intelligent 93 Methods N.Clarkson,K.O.Jones andAJ.Young 7 High Yield Production ofLutein by Heterotrophic Chlorellaprotothecoides 107 in Fed-Batch Systems X.M.Shiand F.Chen 8 Induction ofAstaxanthin Formation inthe Green Microalga Chlorococcum 121 sp. by ReactiveOxygen Species (ROS) under MixotrophicConditionsof Growth R.Y.N.Maand F.Chen v vi 9 PreparativeIsolation and Purification ofAstaxanthin from the Green 127 Microalga Chlorococcumsp.byHigh-SpeedCounter-Current Chromatography RB.Li andF.Chen 10 Changes inContent,Constituentsand DistributionofConstitutiveand 135 ExcretedSugarsofSpirulina(Arthrospira)maxima inNutrient-Limited Batch Cultures J.L.Xia,Z.Y.NieandJ.M.Levert 11 Growth,NutrientAssimilationand CadmiumRemoval bySuspended and 147 Immobilized ScenedesmusacutusCultures: Influence ofImmobilization Matrix R.O.Cafiizares-Villanueva,S.Gonzalez-MorenoandA.R.Dominguez Bocanegra 12 Metal Sorption byMicroalgae for Employment inBiotreatmentof 163 EnvironmentalHeavyMetal Contamination P.Mathad,S.B.AngadiandR.D.Mathad 13 ToxicEffectofTributyltin (TBT)onDifferent Green Microalgal Species 181 N.F.Y.Tam,Y.S.WongandA.M.Y.Chong 14 CatalyticDegradation ofthe Herbicide Glyphosate bythe Paddy Field 195 Isolates ofCyanobacteria T.BalakumarandV.Ravi 15 Effect ofPost-CollectionStorageTimeand Seasononthe Antibacterial 207 ActivityofSelectedSouthern African MarineMacroalgae V.Vlachos,A.T.CritchleyandA.VonHoly 16 Hormesis inBioassayofMacroalgalFungal Propagules 215 M.Barreto,C.J.StrakerandA.T.Critchley 17 BiologicalActivitiesofExtracts from SeveralSpeciesofRohdomelaceae 227 from Fujian Coasts ofChina Y.Zheng 18 Studies ofthe Pharmacologyand ToxicologyofSpirullnamaxima 233 (SMNJU.02) Z.L.LiuandD.H.Cao vii 19 Characterization ofthe icfGGene ClusterImplicated inthe Regulation of 251 Carbon Metabolism inthe CyanobacteriumSynechocystissp. PCC6803 L.Gonzalez,O.Basso,S.BeduandC.C.Zhang 20 PreliminaryStudieson the Genetic Transformation ofSpirulinaplatensis 263 X.c. Zhang,Y.X.Mao,G.G.Wang,RH.Zhang,G.P.YangandZ.H.Sui 21 Effect of Temperature on the Desaturase Gene Translation in Spirulina 271 platensisStrain Cl. A.Hongsthong,P.Deshnium,K.Paithoonrangsarid,P.Phapugrangkul, M.Tanticharoen andS.Cheevadhanarak 22 Application ofaTelemetrySystem to StudyingMicroalgalDynamics and 279 Red Tides inHong Kong I.H.Y.Lamand1.1.Hodgkiss 23 The PitfallsofUsingDifferentClassificationSystems to Quantify 293 BiodiversityofCyanobacteria: ACase Studyfrom Hong Kong Rocky Shores S.Nagarkar Index 303 Preface The term 'algae' is a very difficult one to define. It may appear in textbooks ofBotany, Zoology and Microbiology. Ingeneral, algae are organisms that include seaweeds and a numberofsingle-celledand multicellular microscopicforms, Algae are ubiquitous;they inhabitoceans, freshwater bodies, rocks,soils and trees. There may be over 50,000 algal speciesonthe earth. Man's uses ofalgae have a long history. In China, marine algae were used as food asfarback as600-800BC. Inrecent decades, there has been renewedinterest inthe utilization of algae as sources of health food and high-value chemicals and pharmaceuticals,and foraquaculture, agricultureand wastewatertreatment. Even so, the biotechnological potential of algae is still far from fully exploited. With the aim of promoting algal biotechnology particularly in the Asia-Pacific region, the Fourth Asia Pacific Conference on Algal Biotechnology was planned and successfully held in Hong Kong during 3-6 July 2000. The Conference attracted more than 250 participants from 30 countries and regions. Some 230 papers were presented at the Conference. Among them,40 papers were selected after peer review. Apart ofthe selected papers have been published in Journal of Applied Phycology (Vol. 13 No.4). This book consists of another part of the selected papers, which deal with the various aspects of algal biotechnologywith emphasis onthebiotechnologicalpotential ofalgae. This book cannot bemade possible withoutthe help and effort ofmany. First of allwe are indebtedtothe authors ofthe various chapters fortheir excellentcontributions. Second, we would like to thank the reviewers whose critical comments and constructive suggestions have helped to improve the quality ofthis book greatly. Third, we would liketo thank the generous support ofthe Innovation and Technology Commission ofthe Governmentofthe Hong Kong Special Administrative Region. Finally, wewould liketo acknowledge the assistance ofMartine van Bezooijen and the other staffat Kluwer in producingthe book. Feng (Steven)Chen Vue Jiang Hong Kong,September2001 ix POLYUNSATURATED FATTY ACIDS: BIOLOGICALSIGNIFICANCE, BIOSYNTHESIS, AND PRODUCTION BYMICROALGAE AND MICROALGAE-LIKEORGANISMS C.Y. YAPandF.CHEN Department ofBotany, The University of Hong Kong. Pokfulam Road, Hong Kong, P R.China 1.Abstract Growing interest in the nutritional and pharmaceutical importance of polyunsaturated fatty acids (PUFAs) has created an increasing demand for purified PUFAs. As the traditional sources are insufficient for satisfying this demand, alternative sources are being sought. Microalgaeare agreat sourceof manyhighlyvaluableproductsand they are considered a potential alternative for the large-scale production of PUFAs. Investigations havebeenactivelycarriedoutforscreeningofpotentialmicroalgalstrains and developmentof feasibleculturetechniquesfor the commercialproductionof these vitalcompounds. 2.Introduction Polyunsaturated fatty acids (PUFAs) (Fig. I), especiallythose long-chain fatty acids in the n-3 (originally named 00-3) family, have entered the biomedical and nutraceutical arenasastheyperformmanyvitalfunctions inbiologicalmembranesandasprecursorsof avarietyof lipidregulatorsofcellularmetabolism(Berdanier,2000;Hwang,2000).The beneficialeffectofn-3PUFAswasfirstnoticedbyDyerbergandBangintheearly 1970s. They reported that the Inuit (Greenland Eskimos)population had a lower incidence of heart disease thanthat of an equivalentpopulationof Danes.They also foundthatthese Greenland Eskimos had a favourable plasma lipid profile: with low levels of triglycerides, plasma cholesterol and very low-density lipoproteins (VLDL) and high levels of high-density lipoproteins (HDL) (Dyerberg et aI., 1975). As the Eskimos consumealargeamountofmarinemammalsandarcticfishintheirdietthatarerichinn 3 fatty acids, n-3 PUFAs are presumedto be a major factor responsiblefor the healthy effectof fishoil.ThereportbyDyerberget al. (1975) hadspurredmanyinvestigatorsto performepidemiologicalstudiesinothercountriesto investigatethe beneficialeffectsof n-3 PUFAs on humans. It has become clear that dysfunctions of PUFA-derived eicosanoids may lead to illnesses and disorders including cardiovascular, respiratory, gastrointestinal, renal, dermal and immune diseases, cerebral and ocular underdevelopment, as well as carcinogenesis(Horrocks and Yeo, 1999). Other studies relatingtoPUFAssuchasthebiosynthesismechanismsofPUFAs,exploitationofsources of PUFAs, and productionof PUFAs havealsobeencarriedoutextensively.This review F. ChenandY.Jiang(eds.),AlgaeandtheirBiotechnologicalPotential, 1-32. ©2(0) KluwerAcademicPublishers. 2 C.Y.YAPAND F. CHEN first introduces the biological significance and beneficial effects ofpolyunsaturated fatty acids, then briefly describes the biosynthesis ofPUFAs and finally discusses the various sources of PUFAs and the techniques involved in the microbial production ofPUFAs, with emphasison the biotechnologicalpotentialofmicroalgae. COOH all-cis-5,8,II,14-arachidonicacid(AA,20:4n-6) COOH all-cis-4,7,10,13,16,I9-docosahexaenoicacid(DHA,22:6n-3) Figure I. Chemicalstructure oftwo biologically important PUFAs:AA andDHA. Trivial nomenclatureof PUFA:thelirstnumberdenotesthenumberofcarbonatoms. Thenumberafterthecolondenotesthenumberof doublebonds,andthenumberaftern-denotesthepositionofthelastdoublebondfromthemethylendoffatty acids. 3. Significanceofpolyunsaturated fatty acids 3.1. BIOLOGICALFUNCTIONS Polyunsaturatedfatty acids (PUFAs)are classifiedmainly into four families designated n 3, n-6, n-7 and n-9. The n-3 and n-6 families offatty acids predominate in plants and animals. The parent fatty acid ofthe n-3 family isa-linolenic acid and ofthe n-6 family, linoleic acid. These precursor acids are elaborated into longer chains and more highly unsaturated fatty acids, for examples, arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) byaseries ofdesaturationsand elongations. PUFAs are structural components ofcell and organelle membranes (mainly as sn-2 phospholipids). They are crucial for regulating the membrane structure, fluidity, phase transitions and permeability as well as for the control ofmembrane-associated processes (Berdanier, 2000; Gill and Valivety, 1997). PUFAs also act as the precursors of many metabolites that regulate vital biological functions. In plants, PUFAs are converted by a variety ofenzymes to various oxygenated compounds, acting as anti-infectives, wound response mediators, chemotactic agents, aroma and flavour compounds (Gill and Valivety, 1997). In lower animals, such as insects and marine invertebrates, PUFA derived metabolites mediate cellular processes and ecological responses including metamorphosis, reproduction,chemotaxis and immune function (Gill and Valivety, 1997). PUFAPRODUCTION BY MICROALGAE 3 In higher animals, long-chain PUFAs are precursors of a diverse series of oxygenated fatty acids termed 'eicosanoids' that are crucial to the development and the proper maintenance of homeostasis (Fig. 2) (Hwang, 2000). PUFA-derived eicosanoids in humans including prostaglandins, prostacyclins, thromboxanes and leukotrienes are produced through two main pathways: the cyclo-oxygenase and lipoxygenase pathways, each iscatalyzed by a distinct group ofenzymes (Fig.3).These compounds have a short lifespan.They exert potent biological activities even at very low concentrations and they are linked to many physiological and pathophysiological syndromes (Gurr, 1999; Gurr and Harwood, 1991). 3.2.ESSENTIAL FATTYACIDS:LINOLEIC ACID AND a-LINOLENIC ACID Higher animals includinghumans are unable toproduce fatty acids over CI8 as they only possess M, .15,.16and .19desaturases (lacking .112and .115);they cannot form linoleic acid (LA, l8:2n-6) and a-linolenic (ALA, 18:3n-3) from oleic acid de novo (Fig. 4). However,they can further elaborate LAand ALA to longer PUFAs(Gurr, 1999). LA and ALA are hence considered to be essential fatty acids (EFA) and must be obtained from the diet, asthey are the parent acids ofthe n-3and n-6 families ofPUFAs. Linoleic acid is abundant in several seed oils and its major sources come from the seeds of sunflower, com and soybean (White, 2000). Diets deficient in LA or having unusual ratios ofLA to ALA induce changes in the PUFA composition ofneuronal and glial membranes. Such changes have been linked to alterations in retina and brain functions (Fernstrom, 1999).Linoleic acid deficiency may also lead to skin lesions (Gurr, 1999). A group of isomers of linoleic acid collectively termed conjugated linoleic acid (CLA) has received considerable attention in recent years.They are oxidatively unstable compounds that may form in small amounts during partial hydrogenation, during oxidation, and during normal or abusive heating. Food lipids originating from ruminant animals (beef, dairy and lamb) also contain CLA. CLA appears to exhibit anticarcinogenic and antiatherogenic properties (Ha et aI., 1987, 1989; Hunter, 2000). Effort to confirm and extend the potential benefits ofCLA is expected to be an area of continuingresearch interest. The main dietary sources ofa-linolenic acid are canola oil, rapeseed and soybean oil (White, 2000). A study ofa rural population in France and the UK confirmed that ALA could lower the clotting activity of platelets and the response of platelets to aggregation by thrombin (Renaud, 1995; Renaud et al., 1986). There are researches indicatingthat ALA rich diets may improve some aspects ofcardiovascularfunctions and protect against heart attacks but further confirmation is needed (Gurr, 1999). Nevertheless, ALA is essential as it is the parent acid ofthe physiologically important long-chainPUFAsofthe n-3 family.ALA isconvertedto longer-chainn-3 PUFAs by the same desaturases used for the n-6 or n-9 families, but the extent to which ALA is convertedto long-chain PUFAsinhumans isnotknown (Hwang,2000).
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