Industrial and Food Micro

Biology of the Bacteria and Archaea

  • Biol 2902 Features

Uses for Microbes

  • Beneficial Purposes:

    • Food fermentations

    • Pharmaceuticals

    • Agricultural productivity

    • Sewage treatment and potable water

    • Chemicals

    • Mining

Microbial Applications: Pharmaceuticals

  • Biotransformations or Enzymatic Catalysis:

    • Pregabaline (Lyrica) for neuropathic pain

    • Reboxetine (Edronax) as an antidepressant

    • Montelukast (Singulair) for asthma

    • Sitagliptin (Januvia) for type 2 diabetes

    • Bocepprevir (Victrelis) for hepatitis C

    • Esomeprazole (Nexium) for acid reflux (proton pump inhibitor)

Food Fermentations

  • Lactic Acid Fermentations:

    • Glucose is fermented to lactic acid, dropping pH to 3-5

    • Low pH prevents spoilage/disease-causing bacteria

  • Examples:

    • Pickles, sauerkraut, kimchi, mustard greens, olives

    • Fermented meats: salami, shrimp paste, fish sauce, rakfisk, surströmming, kusaya, hákarl, igunaq

    • Fermented pancakes and flatbreads from rice/legumes

  • Fermented Beverages:

    • Corn/millet/teff/sorghum porridges

    • Fermented milk: yogurt, sour milk, kefir, sour cream, creme fraiche, poi

  • Acetic Acid Fermentations:

    • Vinegar produced from wine/cider as ethanol is oxidized

High pH Fermentations

  • Usually involves Bacillus species and high protein foods like soybeans

  • Amino acids deaminated to ammonia raise pH

  • Example: Ogiri or Iru made from fermented sesame seeds and locust beans

Ethanol Fermentations

  • Glucose fermented to ethanol using Saccharomyces cerevisiae and Zymomonas mobilis

  • Ethanol concentrations: 5% is bacteriostatic, 12% is bacteriocidal

Fungal Fermentations

  • Complex Carbohydrates:

    • Filamentous fungi produce amylases, cellulases, proteases, and lipases

  • Starter Cultures:

    • Aspergillus species break down proteins and lipids for flavor and aroma production

Soy Sauce Fermentation

  • Soybeans steamed and toasted wheat mixed 1:1, crushed, and boiled

  • Inoculated with Aspergillus oryzae

  • Fermented in brine (18% NaCl) with yeast and LAB for 6-18 months

  • Final product is filtered, pasteurized, and bottled

Pharmaceutical Fermentations

  • 25% of pharmaceuticals are natural products; 25% semi-synthetic/synthetic mimics

  • 75% of antibiotics and anti-cancer drugs are natural or semi-synthetic

  • Antibiotic Production:

    • 2/3 produced by bacteria and the rest by fungi (Ascomycetes)

  • Penicillin:

    • Produced by Penicillium chrysogenum

    • Bicyclic compound: β-lactam ring fused to thiazolidine ring

History of Penicillin Production

  • Discovered by Alexander Fleming in 1928

  • Effective against Staphylococci and Streptococci; narrow spectrum antibiotic

  • Howard Florey and Ernst Chain isolated and purified penicillin in 1939

  • Collaboration with USDA in 1941 led to large-scale production

Production Process Development

  • Key Steps:

    • Find product, develop production medium, improve microorganisms, develop production process

  • Random Screening:

    • Isolating useful microorganisms from various environments (soil, sediments)

  • Phenotypic Screening:

    • Isolating natural products (NP) based on effects on other organisms

Production Medium Development

  • Medium impacts natural product production

  • Requires inexpensive, non-inhibitory, compatible components supporting fast growth

Improving Microorganisms

  • Isolates typically produce low yields of NP

  • Techniques: mutagenesis, protoplast fusion, genetic engineering

Production Process Development

  • Aims for rapid growth and product yield

  • Involves successive culturing methods and oxygen provision

Fermentation Management

  • Control of pH, temperature, oxygen levels during fermentation to promote secondary product production

  • Downstream processes involve biomass removal and product recovery

Modern Penicillin Production

  • Strains of Penicillium chrysogenum producing 150,000 IU/mL

  • Large tanks used for growth

  • Production medium typically includes corn steep liquor, glucose, and controlled conditions

Water and Sewage Treatment

  • Potable Water:

    • Made safe through sedimentation, coagulation, sand bed filtration, and membrane filtration

  • Sewage Treatment:

    • Primary (screening/sedimentation), Secondary (BOD removal), Tertiary treatments including disinfection and biological nutrient removal

  • Anaerobic Digestion:

    • Breakdown of proteins, lipids to methane and recovery for use

Sewage Treatment Process Overview

  • Steps from raw sewage to treatment, including processes for sludge handling and ultimately safe disposal.