Valorization of microalgal extracts obtained by pulsed electric - PowerPoint PPT Presentation

PEF4Alg Biotics Valorization of microalgal extracts obtained by pulsed electric fjeld in lactic acid fermentation Aleksandra DjUKIĆ-VUKOVIĆ 1 , Dragana MLADENOVIĆ 1 , Christian GUSBETH 2 , Ljiljana MOJOVIĆ 1 1 Department of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, University of Belgrade, Serbia 2 Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology, Germany

Microalgae Pigments Lipids Proteins - Polyunsaturated fatty acids Chlorella vulgaris CO 2 minerals Biodiesel H2O Not enough! 1000 L photobioreactor , More products to make it economically viable KIT

How to get more from C. vulgaris biomass? Pulsed Electric Field – PEF treatment Institute for Pulsed Power and  of adequate strength and duration Microwave Technology  on eukaryotic and prokaryotic cells  causing increase in cell membrane permeability, if increase in transmembrane voltage surpasses certain value Miklavčič, 2014, Electroporation based technologies and treatments

PEF4Alg Biotics FERMENTATION Lactobacillus rhamnosus Lactobacillus paracasei lactic acid 1. Valorization of 2. Valorization + probiotics released of proteins components Nutrients recycling 3. Biofuel Water Release of soluble small water proteins soluble Lipids Microalgae components biomass Aqueous PEF Ethanolic Protein Lipids treatment extraction s Anaerobic digestion Thermo -chemical conversion Process scheme from IHM/KIT

PEF4Alg Biotics PEF obtained aqueous fraction of microalgae Lactobacillus rhamnosus Lactobacillus paracasei lactic acid As monomer for As chemical poly(lactic) acid As preservative

PEF4Alg Biotics Content of proteins in PEF obtained extracts C. vulgaris suspension was concentrated (of approx. 0.8 g/l) Centrifugation: 10000 g, 6 minutes and resuspended – adjusting conductivity PEF treatment • Continuous treatment, • 10 kV/cm, 100 ns, 4.5 s -1 • 20 h incubation, 23 ˚C • 20-23% of proteins extracted • Protein concentration: 0. 950 g/L (by Lowry) • Role of C/N ratio for lactic acid fermentation Supplementation with fermentable sugars FERMENTATION

PEF4Alg Biotics • Growth of L. rhamnosus and L. paracasei on extracts L. rhamnosus 10 L. paracasei Recommended number of viable cells 8 in probiotics 10 6 -10 9 CFU/g 6 logN 4 2 0 0h 24h Time (h)

 Resistance to gastrointestinal stress (low pH, pepsin, pancreatin,  Antimicrobial activity of L. rhamnosus bile salts) lactic acid Against: • Salmonella Gastric juice enteritidis • Staphylococcus Important aureus • Shigella sonnei probiotic Intestinal juice characteristics of selected  Antibiotic bacteria resistance Resistance to: • Gentamici Antioxidant activity n of • Kanamycin Suseptibility to: • Steptomyc  intact cells • Erytomycin in  intracellular cell free • T etracycline • Vancomyci extracts • Chloramphenicol n • Penicillin G • Ampicilin

PEF4Alg Biotics Lactic acid fermentation • Batch open fermentation – avoiding thermal treatment • 37 ˚C, 24h, 100 rpm • 5% (v/v) inoculum concentration • ~30 g/L initial sugar concentration Strain LA LA LA productivity Stereoselectivity concentration yield L. rhamnosus 24.24 g/L 85% 1.01 g/Lh > 97% L-lactic acid L. paracasei 27.3 g/L 91% 1.14 g/Lh > 97% L-lactic acid Not significant changes were observed in free amino nitrogen concentration!

PEF4Alg Biotics Antioxidant activity ABTS DPPH 100 100 90 90 80 80 70 70 60 60 ABTS, % DPPH, % 50 50 40 40 30 30 20 20 10 10 0 0 n i s l e o n i s l o u e o s r o u i s t Before s r Before t a L. L. contro n i s t a o t a n c o a o t n c n a t n o m c n a L. L. contro e r m c a r m a e p m a h a r p h e . r r L e . r f . L L fermentat f . fermentat e paracasei rhamnosu l L r e o r f o paracasei rhamnosu l e f e b b ion ion s s

Revalorisation of PEF obtained extracts Chlorella vulgaris – FDA approved for human nutrition L. rhamnosus – GRAS status L. paracasei  Can be performed in open fermentation mode – avoiding thermal sterilisation or filtration  But… changes in colour, oxidation, temperature, pH …  After the LA fermentation high antioxidant activity in fermented extracts Fermented extracts centrifugation liquid solids Lyophilisation Lactic acid extraction Food additive - probiotics

Ministry of Education, Science and Technological Development of Republic of Serbia PEF4Alg Biotics Thank you for your attention! adjukic@tmf.bg.ac.rs Department of Biochemical Engineering and Biotechnology Faculty of Technology and Metallurgy University of Belgrade Serbia