Algae Culture

1. Algae Culture Year 2011-2012 Peter Bossier Aäron Plovie Algae Culture 2011-2012

2. Theoretical courses: Mainly based on books -Algal Cultering Techniques from Robert Andersen -Live feeds in marine aquaculture from Josianne StØttrup and Lesley MvEvoy and various papers and reviews (see slides) Practical course: -microalgal growth curve, cell counting -chlorophyl analysis -dry weight determination Exam: Algae Culture 2011-2012

3. Several hundred of billion tonnes of dry weight per year in the oceans, leading up to some 100 million tonnes of renewable resources per year; latest data say 50 billion ton in the oceans. • Hence also important in aquaculture • More than 10000 species in 15 major classes • Taxonomy is ongoing Phytoplankton

4. Ocean primary productivity

5. Chapter 1: What are algae? Phylogenetic relationships, endosymbiosis theory and general features. Algae Culture 2011-2012

6. Tree of life: Algae are spread all over the tree and are therefore a polyphyletic group. Algae Culture 2011-2012

7. All members of the group (D, E, G, H) have the same ancient ancestor (B). No other organism not in-cluded in this group (for example J) has that ancient ancestor (B). All members of the group (E, G) have different ancient ancestors (C, F). Other organisms not in-cluded in this group (D, H) share those ancient ancestors (C, F). Algae Culture 2011-2012

8. Sleeping sickness Uni-and multicellular Mostly multicellular Malaria Uni-and multicellular Plastid loss 2005 Algae Culture 2011-2012

9. How come algal taxa are spread all over tree of life? Endosymbiosis events and plastid losses cause huge algal diversity. Algae Culture 2011-2012

10. Primary endosymbiosis Secundary endosymbiosis Serial secundary endosymbiosis Tertiary endosymbiosis Each endosymbiosis event involves gene transfer between host genome(s) and chloroplast genome(s)! Algae Culture 2011-2012

11. A closer look on endosymbiosis: Algae Culture 2011-2012

12. According to endosymbiosis theory: all plastids in algae are derived from one primary endosymbiosis. However,… (f) Paulinella is a genus of about ninespecies of freshwater amoeboids (Rhizaria, Cercozoa, Euglyphida). Its most famous member is the photosynthetic P. chromatophora which has recently (evolutionarily speaking) taken up a cyanobacterium as an endosymbiont. This is striking because the chloroplasts of all other known photosynthetic eukaryotes derive ultimately from a single cyanobacterium endosymbiont which was taken in probably over a billion years ago in plants (and subsequently adopted into other eukaryote groups, by further endosymbiosis events). The P. chromatophorasymbiontwas related to the Prochlorococcus and Synechococcus cyanobacteria. Algae Culture 2011-2012

13. Algae species relevant to aquaculture Algae Culture 2011-2012

14. Algae species relevant to aquaculture: Microalgae Cyanobacteria Arthrospira platensis (spirulina) Algae Culture 2011-2012

15. Algae species relevant to aquaculture: Microalgae Green algae (Chlorophyceae) Dunaliella salina Algae Culture 2011-2012

16. Algae species relevant to aquaculture: Microalgae Green algae (Chlorophyceae) Chlorella virginica Algae Culture 2011-2012

17. Algae species relevant to aquaculture: Microalgae Green algae (Prasinophyceae) Tetraselmis striata Algae Culture 2011-2012

18. Algae species relevant to aquaculture: Microalgae Dinophyceae Crypthecodinium cohnii Algae Culture 2011-2012

19. Algae species relevant to aquaculture: Microalgae Haptophyceae Isochrysis galbana Algae Culture 2011-2012

20. Algae species relevant to aquaculture: Microalgae Haptophyceae Pavlova lutheri Algae Culture 2011-2012

21. Algae species relevant to aquaculture: Microalgae Eustigmatophyceae Nannochloropsis gaditana Algae Culture 2011-2012

22. Algae species relevant to aquaculture: Microalgae Bacillariophyceae (Diatoms) Skeletonema costatum Algae Culture 2011-2012

23. Algae species relevant to aquaculture: Microalgae Bacillariophyceae (Diatoms) Chaetoceros calcitrans Algae Culture 2011-2012

24. Algae species relevant to aquaculture: Microalgae Bacillariophyceae (Diatoms) Phaeodactylum tricornutum Algae Culture 2011-2012

25. Algal characteristics Algae Culture 2011-2012

26. Algal characteristics Algae Culture 2011-2012

27. Algae species relevant to aquaculture: Macroalgae Rhodophyceae (Red algae) Porphyra spp. (Nori) Algae Culture 2011-2012

28. Algae species relevant to aquaculture: Macroalgae Rhodophyceae (Red algae) Gracilaria spp. Algae Culture 2011-2012

29. Algae species relevant to aquaculture: Macroalgae Phaeophyceae (Brown algae) Laminaria spp. Algae Culture 2011-2012

30. Chapter 2: Microalgal growth. Photosynthesis and its substrates. Algae Culture 2011-2012

31. Microbial growth: During the exponential phase: dC/dt = µC µ = specific growth rate dependent on temperature and light irradiance! Ct= C0 eµt µ = (lnCt – lnC0) / (t – t0) For heterotrophic bacteria mainly expressed in h-1, for algal autotrophs expressed in d-1! Algae Culture 2011-2012

32. Algae Culture 2011-2012

33. During the exponential phase: Doubling time C(t+tD) = 2 C(t) C0 eµ(t+tD) = 2 C0 eµt C0 eµt eµtD = 2 C0 eµt EµtD = 2 µtD = ln(2) tD = ln(2) / µ Algae Culture 2011-2012

34. Algal growth rates Algae Culture 2011-2012

35. Algal characteristics Algae Culture 2011-2012

36. Example: Compare the doubling times of Pavlova lutheri grown in batch culture at 20°C and 60µEm-2s-1 and grown in continuous culture at 20°C in their exponential phases. tD = ln(2) / µ tD = 0.693 / 0.25 = 2.772 days tD = 0.693 / 0.92 = 0.753 days Calculate what cell concentration an axenic batch culture of Chlorella vulgaris will have after 25 days. At the start of the exponential phase, the cell concentration is 10,000 cells per ml. Ct= C0 eµt Ct = 10.000 e0.3*25 Ct = 10,000 * 1808 Ct = 18,080 000 Algae Culture 2011-2012

37. Example: Compare the doubling times of Pavlova lutheri grown in batch culture at 20°C and 60µEm-2s-1 and grown in continuous culture at 20°C in their exponential phases. tD = ln(2) / µ tD = 0.693 / 0.25 = 2.772 days tD = 0.693 / 0.92 = 0.753 days Calculate what cell concentration an axenic batch culture of Chlorella vulgaris will have after 25 days. At the start of the exponential phase, the cell concentration is 10,000 cells per ml. Ct= C0 eµt Ct = 10,000 e0.3*25 Ct = 10,000 * 1808 Ct = 18,080,000 Algae Culture 2011-2012

38. Relationships

39. Production and productivity P expresses production: increase in biomass per unit of time (g/day). We speak of productivity when P is related to the • surface of illumination: g/(m2 day) or • volume of the culture: g/(l day) Algae Culture 2011-2012

40. Productivity In batch culture with no medium renewal: P= (C-C0)V/(t-t0) with V the volume of the reactor In continuous culture where the medium is renewed at an equivalent flow Q (for dilution or harvesting) The variation of concentration in the reactor is the difference between the growth of the biomass and the population reduction following dilution/harvesting or dC/dt= (µ - D)Cwhere D is the dilution rate Q/V Algae Culture 2011-2012

41. Productivity • dC/dt= (µ - D)Cwhere D is the dilution rate Q/V • D>µ: growth can not compensate for dilution, concentration goes down • D=µ: the culture stabilizes around a mean value of C • D<µ: the culture has not reached its steady state and concentration is still increasing • In a stabilized continuous culture (D=µ) the productivity of biomass (per unit of time) Pis the product of the harvesting flow rate DV by the concentration • P=DVC • In theory, a continuous culture can last indefinitely, but there are practical problems such as deposit on light walls or contamination. Algae Culture 2011-2012

42. Photosynthesis: Machinery Algae Culture 2011-2012

43. There are three basic classes of pigments. • Chlorophylls are greenish pigments which contain a porphyrin ring. This is a stable ring-shaped molecule around which electrons are free to migrate. • Because the electrons move freely, the ring has the potential to gain or lose electrons easily, and thus the potential to provide energized electrons to other molecules. • This is the fundamental process by which chlorophyll "captures" the energy of sunlight. There are several kinds of chlorophyll, the most important being chlorophyll "a". • All plants, algae, and cyanobacteria which photosynthesize contain chlorophyll "a". A second kind of chlorophyll is chlorophyll "b", which occurs only in green algae and in the plants. A third form of chlorophyll which is common is called chlorophyll "c", and is found only in the photosynthetic members of the Chromista as well as the dinoflagellates. Algae Culture 2011-2012

44. There are three basic classes of pigments. • Carotenoids are usually red, orange, or yellow pigments, and include the familiar compound carotene, which gives carrots their color. • These compounds are composed of two small six-carbon rings connected by a chain of carbon atoms. • As a result, they do not dissolve in water, and must be attached to membranes within the cell. • Carotenoids cannot transfer sunlight energy directly to the photosynthetic pathway, but must pass their absorbed energy to chlorophyll. For this reason, they are called accessory pigments. Algae Culture 2011-2012

45. There are three basic classes of pigments. • Phycobilins are water-soluble pigments, and are therefore found in the cytoplasm, or in the stroma of the chloroplast. • They occur only in Cyanobacteriaand Rhodophyta. • The bluish pigment phycocyanin is predominant in Cyanobacteria, which gives them their name. • The reddish pigment phycoerythrin is predominant in Rhodophyta, which gives the red algae their common name. Algae Culture 2011-2012

46. Light visible by human eyes (wavelength of 400-700 nm) is also mainly the spectrum that is relevant for photo-synthesis Algae Culture 2011-2012

47. Chloroplast Where are those pigments located in photosynthetisizing cell? Algae Culture 2011-2012

48. Now we know where and how the light energy is captured. What happens with the captured energy? Production of NADPH and ATP for production of fixed carbon (sugars) via Calvin cycle. Algae Culture 2011-2012

49. Captured energy brings electrons in electron transport chain (ETC) from water (2H2O -> 4e− + 4H+ + O2). Electrons are passed to NADP, forming NADPH. ETC creates also a proton (H+) gradient over thylakoid membrane for ATP production Algae Culture 2011-2012

50. Algae Culture 2011-2012