1. FST 508 FERMENTED FOODS (3 units) By Dr. Olusegun Obadina

2. Know Your Lecturers Prof. Olusola OyewoleDr. Olusegun Obadina

3. Part 1Introduction to fermentation processes Type of products resulting from fermentation processes – biomass – enzymes – metabolites (primary + secondary) – recombinant products – transformation processes

4. Part 2Microbial growth kinetics Batch culture x = biomass concentration (g/l) t = time (h) µ = specific growth rate (h -1 ) µ = µ max during exponential phase when nutrients are in excess Exponential phase :

5. Part 2Microbial growth kinetics Transition phase before stationary phase: – Growth rate decreases - by exhaustion of a nutrient - by accumulation of a toxin – Y dependent of strain, growth rate, pH, T, kind of limited substrate, other media compounds At which x: concentration biomass produced (g/l) Y: yield (g biomass/ g substrate) SR: initial substrate concentration (g/l) s: residual substrate concentration

6. Part 3Isolation, preservation and improvement of industrially important m.o. Isolation of micro organisms *ISOLATION from: - COLLECTIONS: ATCC, LMG,… - NATURE: soil, water,… *ENRICHMENT LIQUID CULTURES : - e.g. drying raw material heating raw material CONTINUOUS CULTURE SHAKE FLASKS K S van A > K S van B 1.µ max A > µ max B 2.µ max A < µ max B Selection on µ max or K S 1.Several times subculturing µ max A > µ max B Selection on µ max

7. Part 3Isolation, preservation and improvement of industrially important m.o. Improvement of output of the micro organisms – Step 1: optimization of the culture medium and growth conditions (T, pH, O 2,…) – Step 2: - productivity of a micro organism is determined by the genome so improvement by changing genome - 3 possible routes * Natural mutants * Induced mutants * Recombinant micro organisms

8. Part 4Media Fermentation media – Important parameters for industrial fermentations: 1.Cost and availability  60-80% of the cost 2.Ease of use  holding on temperature 3.Ease of sterilization  denaturation, browning 4.Ease of formulation, mixing 5.Output/ Productivity 6.Impurities  downstream processing 7.Public health

9. Part 5Sterilization Sterilization by : heat moist – 121°C 15min dry – 160°C 2h tyndallization – 100°C 3x filtration depth absolute radiation UV, ,  wave, X disinfectant peroxides, alcohols, aldehydes, quats

10. Part 6Fermenter Design Fermenter Design – Basic Functions 1.Capability to operate aseptically (days-week) 2.Adequate aeration and agitation  metabolic requirements mo 3.Power consumption as low as possible 4.A system of T, pH, O 2,anti-foam,….. control 5.Sampling facilities 6.Extras : automatisation labour cost easy cleaning smooth surfaces good geometry H/D dimensions easy maintenance