Microbial Biotransformation

Introduction

• Microbial biotransformation, also known as microbial metabolism or biocatalysis, refers to the process in which microorganisms, such as bacteria, fungi, and yeasts, transform organic compounds into more desirable products.

• This process is widely used in various industries, including pharmaceuticals, agriculture, and biotechnology, for the production of valuable products such as:

  • Drugs (e.g., antibiotics, anticancer drugs)

  • Food additives (e.g., flavors, sweeteners)

  • Biofuels

  • Fragrances and chemicals

Types of Microbial Biotransformation

1) Phase I Biotransformation

• Involves the introduction of functional groups, such as hydroxyl (-OH), carboxyl (-COOH), or amino (-NH₂), to the original compound.

• Carried out by monooxygenases or cytochrome P450 enzymes.

• Increases the compound's reactivity, making it more susceptible to further modification in Phase II.

• May result in the formation of toxic metabolites requiring additional processing.

2) Phase II Biotransformation

• Involves the conjugation of functional groups introduced in Phase I with endogenous compounds such as glutathione, sulfate, or glucuronic acid.

• Produces more polar and water-soluble compounds for easier excretion.

• Carried out by transferase enzymes and requires ATP hydrolysis.

• Primarily functions as a detoxification mechanism.

Steps in Microbial Biotransformation

1) Substrate Selection

• The substrate is the starting material that undergoes transformation.

• Must be compatible with the selected biocatalyst.

2) Biocatalyst Selection

• The biocatalyst is the enzyme or microorganism responsible for the reaction.

• Should have high efficiency and specificity for the desired transformation.

3) Optimization of Reaction Conditions

• Factors such as temperature, pH, substrate, and biocatalyst concentration must be optimized for maximum yield.

4) Purification of the Product

• After biotransformation, the product is purified from remaining substrates or by-products to meet quality standards.

Advantages of Microbial Biotransformation

1. High Selectivity – Microorganisms selectively transform substrates with high efficiency.

2. Mild Reaction Conditions – Operates at ambient temperature and pressure, reducing energy costs.

3. Enzyme Recycling – Use of immobilized enzymes allows for recycling and improved efficiency.

4. Diversity of Microbial Species – A wide variety of microbial species offer different enzymatic capabilities.

Disadvantages of Microbial Biotransformation

1. Complexity – Involves multiple enzymatic steps, increasing cost and time.

2. Genetic Variability – Differences in microbial strains affect reproducibility.

3. Sterility Requirements – Requires sterile conditions to prevent contamination, increasing cost.

Applications of Microbial Biotransformation

1. Pharmaceutical Industry – Production of antibiotics, steroids, and anticancer drugs.

2. Food and Beverage Industry – Production of food additives, flavors, and fermentation of beverages.

3. Chemical Industry – Production of biofuels, solvents, and biodegradable plastics.

4. Environmental Applications – Biodegradation of pollutants like oil spills and wastewater treatment.