Practical Industrial Microbiology An Introduction

1. Practical Industrial MicrobiologyAn Introduction Prepared By: Prof. Dr. Mohamed Abdel-Wahab

2. Introduction • Industrial microbiologyuses microorganisms, typically grown on a large scale, to produce valuable commercial products or to carry out important chemical transformations. • The actual reactions carried out by microorganisms in industrial microbiology are called biocatalysis. • Originated with alcoholic fermentation processes. • Later on, processes such as production of pharmaceuticals, food additives, enzymes, and basic chemicals were developed.

4. Introduction • An industrial microorganism must: • produce the product of interest in high yield; • grow rapidly on inexpensive culture media available in bulk quantities; • be amenable to genetic manipulation; and, • if possible, be nonpathogenic. • Microbial products of industrial interest include: • Enzymes • Antibiotics, steroids, alkaloids • Food additives (e.g. soya sauce). • Commodity chemicals • Inexpensive chemicals produced in bulk • Include ethanol, citric acid, and many others

5. Introduction • A primary metabolite is a kind of metabolite that is directly involved in normal growth, development, and reproduction. Eg: alcohol, lactic acid etc • Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism. Unlike primary metabolites, absence of secondary metabolites does not result in immediate death. • Primary metabolites are produced during active cell growth, and secondary metabolites are produced near the onset of stationary phase.

6. Secondary metabolites: • Not essential for growth. • Formation depends on growth conditions. • Produced as a group of related compounds. • Often produced by spore-forming microbes during sporulation.

7. Fermentor • Fermentor is where the microbiology process takes place. • Any large-scale reaction is referred to as a fermentation • Most are aerobic processes • Fermentors vary in size from 5 to 500,000 liters • Aerobic and anaerobic fermentors • Large-scale fermentors are almost always stainless steel.

10. PURE CULTURE FERMENTATIONS • industrial ethanol • alcoholic beverages • fermented foods • pharmaceuticals • acetone • butanol • acetic acid • single cell protein • industrial enzymes • biotech products (insulin, growth hormone)

11. Mixed culture fermentation • Bread. • Wine. • Vegetables (e.g. pickles). • Dairy products. (e.g. yogurt). • Composting. • Anaerobic digestion. • Soil and groundwater remediation. • Waste treatment.

12. Culture media & culture methods • History: • The original media used by Louis Pasteur is meat broth. • Cooked cut potato by Robert Koch – earliest solid medium. • Gelatin – not satisfactory - liquefy at 24oC

13. Agar • Used for preparing solid medium • Obtained from seaweeds. • No nutritive value • Not affected by the growth of the bacteria. • Melts at 98oC & sets at 42oC • 2% agar is employed in solid medium

14. Types of culture media • Based on their consistency a) solid medium b) liquid medium c) semi solid medium • Based on the constituents/ ingredients a) simple medium b) complex medium c) synthetic or defined medium d) Special media • Based on Oxygen requirement • Aerobic media • Anaerobic media

15. Based on their consistency Solid media – contains 2% agar • Colony morphology, pigmentation, hemolysis can be appreciated. • Eg: Nutrient agar, Blood agar Liquid media – no agar. • For inoculum preparation, Blood culture, for the isolation of pathogens from a mixture. • Eg: Nutrient broth Semi solid medium – 0.5% agar. • Eg: Motility medium

16. Solid Liquid Semi solid

17. Special media • Enriched media • Enrichment media • Selective media • Indicator media • Differential media • Sugar media • Media for biochemical reactions

18. Simple media / basal media - Eg: NB, NA - NB consists of peptone, meat extract, NaCl, - NB + 2% agar = Nutrient agar

19. Complex media • Media other than basal media. • They have added ingredients. • Provide special nutrients. Synthetic or defined media • Media prepared from pure chemical substances and its exact composition is known. • Eg: peptone water – 1% peptone + 0.5% NaCl in water.

20. Enriched media • Substances like blood, serum, egg are added to the basal medium. • Used to grow bacteria that are exacting in their nutritional needs. • Eg: Blood agar, Chocolate agar

21. Chocolate agar Blood agar

22. Enrichment media • Liquid media used to isolate pathogens from a mixed culture. • Media is incorporated with inhibitory substances to suppress the unwanted organism. • Eg: • Selenite F Broth – for the isolation of Salmonella, Shigella • Alkaline Peptone Water – for Vibriocholerae

23. Selective media • The inhibitory substance is added to a solid media. Eg: • Mac Conkey’s medium for gram negative bacteria • TCBS – for V. cholerae • LJ medium – M. tuberculosis • Wilson and Blair medium – S. typhi • Potassium tellurite medium – Diphtheria bacilli

24. Mac Conkey’s medium TCBS

25. Potassium Tellurite media LJ media

26. Indicator media • These media contain an indicator which changes its colour when a bacterium grows in them. • Eg: • Blood agar • Mac Conkey’s medium • Christensen’s urease medium

27. Urease medium

28. Differential media • A media which has substances incorporated in it enabling it to distinguish between bacteria. • Eg: Mac Conkey’s medium • Peptone • Lactose • Agar • Neutral red • Taurocholate • Distinguish between lactose fermenters & non lactose fermenters.

29. Lactose fermenters – Pink colonies • Non lactose fermenters – colourless colonies

30. Anaerobic media • These media are used to grow anaerobic organisms. • Eg: Robertson’s cooked meat medium, Thioglycolate medium.

31. Preservation of pure cultures • Culture transfer: ( disadvantages: contamination and genetic changes). • Refrigeration from 0°C to 5°C (disadvantages: short term storage). • Low temperature freezing: (ultra low temperature “-80°C” and liquid nitrogen “-196°C”). • Lyophilization: (freeze with dry ice and acetone, sublime off water “dries cells without disruption”. • Under mineral oil. • Dry spores: (in sterile soil or sand).