FST 508 FERMENTED FOODS (3 units)

FST 508FERMENTED FOODS(3 units) By Dr. OlusegunObadina

Know Your Lecturers Prof. Olusola Oyewole Dr. Olusegun Obadina

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

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

Part 2 Microbial 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

Part 3 Isolation, 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 Selection on µmax or KS • KS van A > KS van B • µmax A > µmax B • µmax A < µmax B Selection on µmax • Several times subculturing • µmax A > µmax B

Part 3 Isolation, 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, O2,…) • 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

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

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

Part 6 Fermenter Design • Fermenter Design – Basic Functions • Capability to operate aseptically (days-week) • Adequate aeration and agitation  metabolic requirements mo • Power consumption as low as possible • A system of T, pH, O2 ,anti-foam,….. control • Sampling facilities • Extras : automatisation labour cost easy cleaning smooth surfaces good geometry H/D dimensions easy maintenance

FST 508 FERMENTED FOODS (3 units)