Πανεπιστημιούπολη 26504, Ρίο, Αχαΐα microbiology.upatras@gmail.com +302610969232

#2 | 4th International Symposium on Microbial Lipids

Occurrence of Fusarium oxysporum strains on the coasts of Ionian Sea (Greece) and prospects for the production of oils and pigments of high-added value

Panagiotis Dritsas1, Kerasia-Vasileia Bartsoka2, ChristosAnagnostakis1,Elias Asimakis2,George Tsiamis2, George Aggelis1
1Unit of Microbiology, Section of Genetics, Cell and Developmental Biology, Department of Biology, University of Patras, 26504 Patras, Greece
2Laboratory of Systems Microbiology and Applied Genomics, Department of Sustainable Agriculture, University of Patras, 30131 Agrinio, Greece

Fusarium is a genus of cosmopolitan filamentous fungi belonging to Ascomycetes. Some species, like Fusarium oxysporum, are producers of a great number of secondary metabolites with remarkable chemical diversity and significant bioactivities. The aim of this study was to investigate the ability of eight newly isolated strains of Fusarium oxysporum from the Ionian Sea of Greece to grow under laboratory conditions and produce metabolites of high-added value, focusing on lipids and pigments production. In preliminary experiments it was shown that the strains grew well on organic media having glucose rather than glycerol as carbon source. Thus, Potato Dextrose Broth (PBD) was selected for submerged cultures in 250cc Erlenmeyer flasks. All strains gained high amounts of dry biomass (i.e., 11.3 – 11.8 g/L) at approximately 72 h of cultivation, though lipid  accumulation was low (up to 2.7%, w/w). However, when the strains were cultured on a medium containing PDB at half the recommended concentration and supplemented with glucose at 40 g/L (thus having a high C:N ratio), an increased lipid accumulation was recorded (i.e., 13.0 – 30.0%, w/w), though the production of biomass was lower (i.e., 7.4 ± 0.0 – 10.1 ± 1.0 g/L). Additionally, in all cases considerable amounts of orange and red pigments were excreted in the growth medium, the production of which increased by 3 to 10 times, depending on the strain, when glucose was added to the growth medium. Lastly, the fungal cell mass contained proteins (i.e., 47.6 – 62.5, % w/w) and polysaccharides (i.e., 35.1 – 43.6 %, w/w) in significant levels. The biochemical profiles of the isolates revealed their suitability for use in various industrial applications, while these findings can give the impulse for the design of specific culture conditions which will lead to the production of these highadded value metabolites in more efficient ways for large-scale applications.

DGF – 4th ISML – Fusarium

#1 | 4th International Symposium on Microbial Lipids

Growth patterns in Artificial Sea Waters of two newly-isolated Picochlorum oklahomense strains from the coasts of Ionian Sea (Greece)

Panagiotis Dritsas, George Aggelis
Unit of Microbiology, Section of Genetics, Cell and Developmental Biology, Department of Biology, University of Patras, 26504 Patras, Greece

Microalgae constitute a diverse group of photosynthetic microorganisms of high importance for basic research and biotechnological applications. The aim of this study was the investigation of the effect of nitrogen and phosphorus concentration on biomass and nutritionally interesting cellular components (i.e., lipid, protein) production of two newly-isolated Picochlorum oklahomense strains from the Ionian Sea (Greece). All the experiments were performed in an Open Pond Simulating Reactor – OPSR of total volume 8.7 L (working volume, Vw = 5.0 L) under constant illumination 232 μmol m-2 s-1 for approximately 450 h. A modified Artificial Sea Water (mASW) was served as growth medium, in three variations. Specifically, mASW (i.e. control, containing KNO3: 1.0 g L-1 and KH2PO4: 0.07 g L-1); mASW containing KNO3: 0.1 g L-1; and mASW containing KH2PO4: 0.02 g L-1. Both strains gained satisfying amounts of dry biomass (i.e., 299.3 ± 9.6 mg L-1 and 421.1 ± 30.8 mg L-1  for P. oklahomense SAG4.4 and P. oklahomense PAT3.2B, respectively) and accumulated considerable levels of lipids (i.e., 9.4 ± 1.1, % w/w, and 11.5 ± 0.3, % w/w, respectively) when cultivated under control conditions. Nitrogen limitation affectedboth strains in a negative way as they produced less biomass (i.e., 195.7 ± 10.2 mg L1 for P. oklahomense SAG4.4 while P. oklahomense PAT3.2B gained only 98.0 ± 4.6 mg L-1) and lipids (e.g., P. oklahomense PAT3.2B gained up to 5.1 ± 1.0, % w/w).Under phosphorus limitation, the two strains presented differences in terms of biomass production. P. oklahomense SAG4.4 gained almost 1.8 times higher biomass (i.e. 529.0 ± 36.9 mg L-1), while lipid accumulation was slightly lower (i.e. 5.7 ± 1.6, % w/w) comparing to the control experiment. On the other hand, P. oklahomense PAT3.2B marked low biomass levels (i.e. 125.3 ± 4.1 mg L-1 ) but similar levels of intracellular lipids (i.e. 6.0 ± 2.5, % w/w) comparing to its control experiment. Lastly,the microalgal cell mass in all cases contained proteins (ranging 29.1 – 49.2, % w/w) in considerable levels. The biochemical profiles of the two isolates, especially when cultivated in environment rich in nitrogen and phosphorus, highlight them as suitable candidates for use in various industrial applications.

DGF – 4th ISML – Microalgae

Microalgae from the Ionian Sea (Greece): Isolation, molecular identification and biochemical features of biotechnological interest

ORIGINAL ARTICLE

Panagiotis Dritsas, Elias Asimakis, Alexandra Lianou, Maria Efstratiou, George Tsiamis, George Aggelis, Microalgae from the Ionian Sea (Greece): Isolation, molecular identification and biochemical features of biotechnological interest, Algal Research, Volume 74, 2023,
103210, ISSN 2211-9264, https://doi.org/10.1016/j.algal.2023.103210.

Abstract

Microalgae are photosynthetic organisms of high importance for basic research and biotechnological applications. The aim of this study was the isolation of new microalgal strains from the Ionian Sea (Greece) and their taxonomic and biochemical characterization. Twelve microalgal isolates were identified using molecular techniques and were classified to the genera Picochlorum, Nannochloropsis, Tetraselmis, Chlorella and Nephroselmis. Subsequently, their ability to grow under laboratory conditions was evaluated. Tetraselmis sp. strain KAT3.M2 growing in modified artificial seawater (mASW) produced biomass in high concentrations (approaching 1600 mg L−1 of dry biomass), while P. costavermella strain VAS2.5 exhibited the highest lipid content (exceeding 19 % wt/wt of dry biomass). Most of the isolates synthesized polyunsaturated fatty acids (mainly eicosapentaenoic and a-linolenic acid) in significant quantities, while Nephroselmis pyriformis PAT2.7 produced more saturated fatty acids suitable for biodiesel manufacture. Microalgal cell mass of all strains contained considerable levels of proteins ranging from 16.5 % to 57.6 % (wt/wt). Furthermore, the strains belonging to the genera Tetraselmis, Chlorella, Nephroselmis as well as the Nannochloropsis gaditana AIT5.1 strain, synthesized polysaccharides at also considerable levels (ranging from 13.4 to 31.5 %, wt/wt). Additionally, two of the isolated Picochlorum strains, cultivated in mASW in a stirred-tank reactor, exhibited manifold production of biomass and reserve materials (i.e., polysaccharides, lipids) compared to the experiments in Erlenmeyer flasks. Lastly, the isolates were examined for their biofilm-forming capacity, a feature of interest as a cost-effective means of biomass harvesting in large-scale applications and wastewater treatment. It was shown that the biofilm formation ability was strain-specific and, closely related to the medium’s pH and the time of incubation. Tetraselmis sp. strain KAT.3M2 and N. gaditana strain VAT4.3 proved to be the strongest biofilm formers. The biochemical profiles of these new isolates showcased their suitability for use in aquaculture and various industrial applications.

2023 AOCS Annual Meeting & Expo

Lipid production of microalgae isolated from the Ionian Sea of Greece

Authors: Panagiotis Dritsas1, Elias Asimakis2, George Tsiamis2, George Aggelis1

  • 1Greece, University of Patras/Department of Biology
  • 2Greece, University of Patras/Department of Sustainable Agriculture

Microalgae are photosynthetic organisms, considered to be a biological material of high importance for basic research and many biotechnological applications. The aim of this study was the isolation of microalgal strains from the Ionian Sea of Greece, their molecular identification and biochemical characterization with emphasis on their ability to accumulate lipid reserves. The lipids which are rich in polyunsaturated fatty acids (PUFAs) are used as additives in human and animal nutrition, in the pharmaceutical and chemical industries, while more saturated lipids towards biodiesel production. 13 strains of microalgae were isolated, belonging to the genera Picochlorum, Nannochloropsis, Tetraselmis, Chlorella and Nephroselmis as revealed by the molecular identification by PCR amplification of the 18S rRNA gene and the ITS (internal transcribed spacer) region. All strains grew satisfactorily when they were cultured in 500cc Erlenmeyer flasks containing 100 mL of artificial seawater, under continuous illumination of 387 μmol m-2 s-1 with initial population of 1.5 x 106 cells/mL. Especially, Tetraselmis sp. reached approximately 1,600 mg L-1 of dry biomass after 450 h. In terms of lipid accumulation, P. costavermella was placed first, exceeding 19% w/w of dry biomass. The major PUFA synthesized by Nannochloropsis strains was eicosapentaenoic acid, while the strains belonging to the genera Picochlorum, Tetraselmis and Chlorella synthesized a-linolenic acid in significant quantities. On the contrary, Nephroselmis pyriformis produced fatty acids which were more suitable for biodiesel manufacture. Additionally, microalgal cell mass of all strains contained proteins and polysaccharides in considerable levels. The biochemical profiles of these new isolates revealed their suitability for use in aquaculture and various industrial applications, highlighting the probability of a more efficient and economical production of high-added value products in large scale applications by the use of newly-isolated microalgae.

2023 AOCS Annual Meeting & Expo – Panagiotis Dritsas.Oral Presentation

#2 | 4th International Conference for Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability

Cultivation of marine microalgae, native of the Ionian Sea, in open raceway pond – Production of high-value compounds

Stefania Patsialou1,4, Panagiotis Dritsas2, Yannis Kotzamanis3, George Aggelis2, Athanasia G. Tekerlekopoulou1, Dimitris V. Vayenas4

1 Department of Sustainable Agriculture, School of Agricultural Sciences, University of Patras, 30100 Agrinio, Greece
2 Department of Biology, School of Natural Sciences, University of Patras, 26500 Patras, Greece 3 Hellenic Centre for Marine Research/Institute of Marine Biology, Biotechnology and Aquaculture, 19013 Anavyssos, Greece
4 Department of Chemical Engineering, School of Engineering, University of Patras, 26500 Patras, Greece

In recent years there is a great interest for high added value bioproducts derived from marine microalgae. These valuable metabolic compounds (e.g. lipids, carbohydrates, pigments, proteins), are well known for their potential use in biotechnological applications in various fields, such as pharmaceuticals, cosmetic products, human and animal nutrition and the production of renewable energy sources. In this work four different marine microalgae species (isolated from coastal areas of the Ionian Sea) were cultivated in a paddle wheel, open, raceway pond photobioreactor (PBR) of 40 L operating volume. Specifically, the strains Nephroselmis pyriformis, Picochlorum costavermella, Picochlorum oklahomense and Nannochloropsis gaditana were examined. Initially, stock cultures of strains were gradually scaled up from 100 ml flasks to 6L aquariums with the aim to inoculate the raceway pond. It should be mentioned that the growth medium was sterile artificial seawater of salinity 33 ‰. In all experiments the pH was remained at the value of about 8.5, the temperature was 23oC ±1oC, while continuous illumination (2000-2500 lux) was employed from three LED lamps. Also, the culture was circulated in the pond using a double 4-bladed paddlewheel driven by an electric motor rotating at 35 rpm. Biomass growth was examined for all the above-mentioned microalgae strains, for a period of 19 days. N. pyriformis and P. costavermella presented similar final biomass concentration, 419.1±79.9 mg/L and 405.7±0.2, respectively, while N. gaditana reached a lower value, that of 359.5±42.7 mg/L. An even lower value (212.9±11.4 mg/L) was presented for P. oklahomense. Lipid content was varied greatly by species, with values of 30.7±4.5, 64.7±0.3, 75.2±5.9 and 28.3±3.8 mg/L, for N. pyriformis, N. gaditana, P. costavermella and P. oklahomense, respectively. The final produced biomass will also be characterized for its protein, polysaccharide, amino acid and pigment content, in order to assess the use of biomass in various biotechnological applications.

Keywords: marine microalgae, Ionian Sea, bioproducts

BIORESTEC 23 – Stefania Patsialou

#1 | 4th International Conference for Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability

Isolation of new microalgal strains from the Gulf of Patras (Greece) and investigation of their potential biotechnological applications

Authors: Panagiotis Dritsas1, Elias Asimakis2, George Tsiamis2, George Aggelis1
1Greece, University of Patras/Department of Biology 2Greece, University of Patras/Department of Sustainable Agriculture

Microalgae are phytoplankton, found in all types of aquatic systems. Due to their ability to synthesize metabolites of high-added value in significant quantities, basic research and biotechnology sectors recognize them as biological material of high importance. The goal of this study was the isolation of microalgal strains from the Gulf of Patras (Greece), their molecular identification and biochemical characterization. Emphasis was given on their ability to accumulate lipid reserves, as lipids rich in polyunsaturated fatty acids (PUFAs) are used as additives in food, pharmaceutical and chemical industries, while more saturated lipids can be utilized towards biodiesel production. The molecular identification, by PCR amplification of the 18S rRNA gene and the ITS (internal transcribed spacer) region, revealed that the 6 isolated strains belong to the genera Picochlorum, Nannochloropsis and Nephroselmis. All strains were cultured in 500cc Erlenmeyer flasks containing 0.1 L of artificial seawater and grew satisfactorily. Especially, in terms of dry biomass production, Nannochloropsis sp. from Patras city port marked the highest levels (exceeding 900 mg/L) after 450 h, while P. costavermella was placed first in lipid accumulation (i.e., 19% w/w of dry biomass). Significant quantities of PUFAs were synthesized by the Picochlorum and Nannochloropsis strains (mainly a-linolenic and eicosapentaenoic acid respectively), while the fatty acids of Nephroselmis pyriformis were suitable for biodiesel manufacture. Moreover, all strains accumulated notable amounts of proteins and carbohydrates. Furthermore, the 2 isolated Picochlorum strains were cultured in a Stirred Tank Reactor. In this setup, biomass production was much higher (2-3 times), although slight differences were observed in terms of storage material accumulation between the two types of bioreactors. In conclusion, the biochemical profiles of the isolates showcased their potential suitability in various applications, like aquaculture, which is a sector of crucial importance for the economy of many countries located in the Mediterranean Sea.

BIORESTEC 23 – Panagiotis Dritsas

16η Ημερίδα Μεταπτυχιακών Φοιτητών Τμήματος Βιολογίας

Απομόνωση μικροφυκών από θαλασσινά νερά του Ιονίου πελάγους και βιοχημικός χαρακτηρισμός τους

Παναγιώτης Δρίτσας1, Ηλίας Ασημάκης2, Γεώργιος Τσιάμης2, Γεώργιος Αγγελής1

1 Εργαστήριο Μικροβιολογίας, Τομέας Γενετικής, Βιολογίας Κυττάρου και Ανάπτυξης, Τμήμα Βιολογίας, Πανεπιστήμιο Πατρών, Ελλάδα

2 Εργαστήριο Μικροβιολογίας Συστημάτων και Εφαρμοσμένης Γονιδιωματικής, Τμήμα Μηχανικών Περιβάλλοντος, Πανεπιστήμιο Πατρών, Ελλάδα

Περίληψη: Σκοπός της εργασίας είναι η απομόνωση στελεχών μικροφυκών από νερά του Ιονίου πελάγους, η μοριακή ταυτοποίηση και ο βιοχημικός χαρακτηρισμός τους. Έμφαση δίνεται στη διερεύνηση της ικανότητάς τους να συσσωρεύουν αποθεματικά λιπίδια. Τα πλούσια σε πολυακόρεστα λιπαρά οξέα λιπίδια των μικροφυκών έχουν ποικίλες εφαρμογές ως πρόσθετα στη διατροφή ανθρώπου και ζώων, στη φαρμακευτική και χημική βιομηχανία, ενώ περισσότερο κορεσμένα λιπίδια χρησιμοποιούνται στη βιομηχανία παραγωγής βιοντήζελ. Έπειτα από δειγματοληψίες κατά μήκος της ακτογραμμής του Ιονίου πελάγους απομονώθηκαν 13 στελέχη μικροφυκών, από τα παράλια των νομών Αχαΐας και Αιτωλοακαρνανίας. Όπως προέκυψε μετά τη μοριακή τους ταυτοποίηση με ενίσχυση PCR του γονιδίου 18S rRNA και της περιοχής ITS (internal transcribed spacer) (περιλαμβάνει τμήμα των 18S rRNA, 28S rRNA, τις μεταγραφόμενες μεταβλητές περιοχές ITS1, ITS2 και το 5,8S rRNA), τα απομονωθέντα στελέχη ανήκουν στα γένη: Picochlorum, Nannochloropsis, Tetraselmis, Chlorella και Nephroselmis. Τα στελέχη καλλιεργήθηκαν για 450 h σε τεχνητό θαλασσινό νερό σε Erlenmeyer φιάλες των 500cc ενεργού όγκου 100 mL, υπό διαρκή φωτισμό έντασης 387 μmol m-2 s-1 και περιοδική ανακίνηση, με αρχικό πληθυσμό 1,5 x 106 κύτταρα/mL. Όλα τα στελέχη αυξήθηκαν ικανοποιητικά, ιδιαίτερα όσα ανήκουν στο γένος Picochlorum. Ειδικότερα, το μεγαλύτερο πληθυσμό έφτασε η καλλιέργεια του Picochlorum oklahomense με 75 x 106 κύτταρα/mL (ξηρή βιομάζα, x = 320,34 ± 55,06 mg/L), απομονωμένο από τον Πατραϊκό κόλπο, όμως τη μεγαλύτερη παραγωγή ξηρής βιομάζας παρουσίασε το Tetraselmis levis (x = 1558,70 ± 75,20 mg/L). Το υψηλότερο επίπεδο συσσώρευσης αποθεματικών λιπιδίων εμφάνισε το Picochlorum costavermella με ποσοστό που υπερέβη το 19% επί της ξηρής βιομάζας.

Δείτε εδώ

One-Day Conference “INVALOR Research Infrastructure – Valorization of Industrial and Agro-Industrial Waste and By-products for the Production of New Added-Value Materials”

Participation of Panagiotis Dritsas to the One-Day Conference “INVALOR Research Infrastructure – Valorization of Industrial and Agro-Industrial Waste and By-products for the Production of New Added-Value Materials”, March 29 2021, Online, with the presentation entitled “The use of microalgae for the production of high-added value products and the prospect of their utilization by the aquaculture of Greece”

Presentation

Ημερίδα «Ερευνητική Υποδομή INVALOR – Αξιοποίηση Βιομηχανικών και Αγροτοβιομηχανικών Αποβλήτων και Παραπροϊόντων για την Παραγωγή Νέων Υλικών Προστιθέμενης Αξίας»

Συμμετοχή του Παναγιώτη Δρίτσα στην Ημερίδα «Ερευνητική Υποδομή INVALOR – Αξιοποίηση Βιομηχανικών και Αγροτοβιομηχανικών Αποβλήτων και Παραπροϊόντων για την Παραγωγή Νέων Υλικών Προστιθέμενης Αξίας», 29 Μαρτίου 2021 (Διαδικτυακά), με την παρουσίαση «Η χρήση μικροφυκών για την παραγωγή προϊόντων υψηλής  προστιθέμενης αξίας και η προοπτική εκμετάλλευσής τους από τις υδατοκαλλιέργειες της Ελλάδας»

Παρουσίαση

High-added value products from microalgae and prospects of aquaculture wastewaters as microalgae growth media

MINI REVIEW

Marianna Dourou, Panagiotis Dritsas, Mohamed N Baeshen, Ahmed Elazzazy, Ammar Al-Farga, George Aggelis, High-added value products from microalgae and prospects of aquaculture wastewaters as microalgae growth media, FEMS Microbiology Letters, Volume 367, Issue 12, June 2020, fnaa081, https://doi.org/10.1093/femsle/fnaa081

Abstract

Aquaculture plays an important role in human nutrition and economic development but is often expanded to the detriment of the natural environment. Several research projects, aimed at cultivating microalgae in aquaculture wastewaters (AWWs) to reduce organic loads and minerals, along with the production of microalgal cell mass and metabolic products, are underway. Microalgal cell mass is of high nutritional value and is regarded as a candidate to replace, partially at least, the fish meal in the fish feed. Also, microalgal cell mass is considered as a feedstock in the bio-fuel manufacture, as well as a source of high-added value metabolic products. The production of these valuable products can be combined with the reuse of AWWs in the light of environmental concerns related with the aquaculture sector. Many research papers published in the last decade demonstrate that plenty of microalgae species are able to efficiently grow in AWWs, mainly derived from fish and shrimp farms, and produce valuable metabolites reducing the AWW pollutant load. We conclude that bio-remediation of AWWs combining with the production of microalgae cell mass and specific metabolites is probably the most convenient and economical solution for AWWs management and can contribute to the sustainable growth of the aquaculture.