Environmental Biotechnology Quiz

Environmental Biotechnology

• Environmental biotechnology focuses on utilizing biological processes to manage waste.

Waste Management Hierarchy

• Reduce: Generating less waste daily.
• Reuse: Repairing or repurposing items.
• Recycle: Transforming materials into new products.
• Recovery: Recovering energy from waste.
• Disposal: Landfilling when no other options exist.
• Reduce, Reuse, Recycle (3R) is a preferred option and is the best environmental approach when achievable.
• Recovery and Disposal are the last resorts.

Recycling Objectives

• Reduces the use of raw materials.
• Minimizes landfill use.
• Protects the environment by preventing incineration.

Waste Types

• Mining and oil/gas production (75%) is the largest producer of waste.
• Agriculture (13%)
• Industry (9.5%)
• Sewage sludge (1%)
• Municipal (1.5%)

Agricultural Crop Residues

• Cereal crop residues (wheat, rice, corn, barley): Provide 90% of human food needs, but residue weight exceeds grain production.
• Leguminous crop and vegetable residues (soybean, peanut, beans, potato, sweet potato): Other plant residues.

Crop Residue Uses

• Feed and livestock bedding.
• Increasing soil fertility (improving texture).
• Controlling wind & water erosion.
• Providing humus to condition soil and nutrient supply to microorganisms.
• Supplying organic nitrogen, phosphorus, and potassium to the soil.

Chemical Composition of Crop Residues

• Cellulose: A linear glucose polymer with beta 1-4 linkages, insoluble in water.
• Hemicellulose: A group of heteropolysaccharides associated with cellulose and lignin. Common types include xylan, glucomannan, arabinoxylan, xyloglucan.
• Lignin: A complex, three-dimensional polymer of phenyl-propane units, linked by various bond types.

Pretreatment Methods

• Physical Treatment:
  • Milling
  • Steaming
  • Gamma radiation (reduces crystallinity, polymerization & increases water solubility, decreases particle size).
• Chemical Treatment:
  • Sodium hydroxide
  • Sulphuric acid (reduces cellulose crystallinity. Increases cellulose digestibility, decomposes lignin structure)

Advanced Treatments

• Combined physical and chemical treatments (e.g., steaming combined with chemical treatments using varying concentrations of acid/alkaline solutions).
• Biological treatments using microorganisms and enzymes.

Advantages of Waste Recycling

• Numerous products, including xylitol, super absorbents polymers, fuel briquettes, high-calorific fuels, mushroom cultivation, fish feed, animal feed, bio-fertilizers, biogas, bio-polymers, organic acids, and carbon fiber.

Rice Straw Production

• Extensive data on rice straw production for various governorates in a specific timeframe (e.g., 2006-2008) was included, but specifics are omitted.

Rice Straw Recycling Products

• Yeast biomass
• Ethanol
• Mushroom
• Compost

Rice Straw Composition

• Lignin (15%-25%)
• Hemicellulose (23%-32%)
• Cellulose (38%-50%)

Cellulose Structure Diagrams (visualized in the slide presentation)

Rice Straw Recycling Process

• Raw materials (cellulose) -> Milling -> Acid hydrolysis (1% H₂SO₄ or HCl + Steaming at 121°C/hr) -> Filtration

Liquid Phase Treatment

• Treated to remove impurities and neutralize to pH 7 using (NaOH or KOH)
• Utilized in yeast biomass production and alcoholic fermentation.

Solid Phase Treatment

• Mixed with water for neutralizing and filtering to pH 7.
• Used in solid-state fermentation for feed production.
• Used in cellulase production (saccharification of cellulosic materials, converting cellulose to soluble sugars).

Biomass Production of Yeast Cells

• Rice straw pretreatment liquid byproduct contains high levels of carbon and minerals – readily adaptable for biomass production.

Yeast Biomass Production Parameters

• Different liquid rice straw solutions are used to study their capability in producing yeast biomass.
• Dilutions of solutions in increasing concentrations are studied to maximize efficiency.
• Sterilization through autoclave procedures are documented, following standard procedures.
• Yeast culture inoculations and subsequent incubation under controlled temperatures for specified times are discussed.

Ethanol Production

• Pretreated rice straw liquid byproduct is rich in carbon and minerals – easily altered for ethanol production.

Ethanol Production Methods

• Treatments using different dilutions are documented in glass jars under specified conditions.
• Treatments are described, including sterilization protocols, incubation parameters, and the use of control samples.

Fermentation

• Alcoholic fermentation (conversion of sugar into carbon dioxide and ethanol) by yeast enzymes.
• Optimal fermentation conditions:
  • Temperature (18-24°C)
  • Sugar concentration (not exceeding 1 kg/4.5 L) to prevent feedback inhibition
  • pH (3.5-5.5)
  • Nutrients
  • Oxygen (required for initial yeast replication)

Ethanol Detection

• Utilizing oxidation tests with chromic acid. 

Specific Microorganisms

• Trichoderma viride
• Trichoderma reesei
• Saccharomyces cerevisiae
• Zymomonas mobilis

Recyclable Materials Characteristics

• Easily separated from other waste.
• Readily available in large quantities.
• Economically valuable.

Test your knowledge on environmental biotechnology and waste management strategies. This quiz covers the waste management hierarchy, recycling objectives, and various types of waste. Understand how biological processes play a vital role in managing waste and protecting our environment.