chap 1

• Environment and its components ◦ Environment refers to the surroundings of an object, or ◦ The Natural environment, all living and non-living things that occur naturally on Earth OR ◦ Physical and biological factors along with their chemical interactions that affect an organism. ◦ Environment has biotic and abiotic components in it.
• Biotic components comprise of the microorganism that dwell in the environment and the abiotic components are made up of temperature, pressure, light moisture etc.
• Pollution is the condition that disturbs the harmony between the biotic and abiotic components of the environment
• Increased population pressure has led to overexploitation of land, water, air resources, and destruction of bio-wealth and biodiversity
• Introduction of pollutants like xenobiotics affects the environment the most by disturbing the biotic components
• Environmental biotechnology is the application of biotechnology to all aspects of the environment, covering existing pollution in terms of detection and bioremediation of contaminants
• Treatment is required for industrial, agricultural, and domestic process wastes
• An urgent need exists to reduce the production of pollutants at the source
• Clean technology is emphasized as a solution to pollution issues
• Areas of application for biotechnology Environmental Biotechnology must deal with high volumes of low-value wastes, products and services. Type of pollutant Examples Inorganic Metals Cd, Hg, Ag, Co, Pb, Cu, Cr, Fe,: Radionucleotides ,Nitrates, nitrites, phosphates ,Cyanides, Asbestos ,Organic ,Biodegradable - Sewage, domestic, agricultural and process waste; Petrochemical Oil- diesel, BTEX; Synthetic -Pesticides, organohalogens, PAHs; Biological pathogens -Bacteria, viruses; Gaseous Gases- SO2 , CO2 , nitrous oxide, methane; Volatile -CFCs, VOCs Particulates
• Environmental pollutants range from metals to gases
• Three main problems caused by environmental pollutants:

  a. Existing pollution of land, water, and air (due to old industries and industrial processes)

  b. Current industrial, agricultural, and domestic processes producing pollutants, including accidents and spills

  c. Industrial, agricultural, and transport sectors create pollutants that could be reduced by introducing a more sustainable, renewable source of raw materials and energy
• Biotechnological processes can address the problems caused by environmental pollutants
• Before treating pollution, it's crucial to determine the pollutants present
• Chemical techniques are commonly used to determine the concentration of pollutants in samples
• Bioindicators and biomarkers can be used to monitor pollution in situ
• • Bioindicators are whole organisms that are representative of their environment and whose population changes are used to estimate the effects of pollutants. Biomarkers are physiological, biochemical and molecular characteristics of organisms removed from the environment and the characteristics chosen are those that will be affected by pollutants. Microorganisms containing green fluorescent protein under the control of a gene that responds to pollutants in vitro have been developed using recombinant gene technology.
• Genetic manipulation has produced luminescent microorganisms used to test for toxicity in addition to the Ames test
• Once a pollutant is detected and quantified, it needs to be removed and degraded
• Bioremediation is the process where aerobic and anaerobic heterotrophic microbes reduce the concentration, remove, and detoxify pollutants from the environment
• Heavy metals released into the environment pose a severe problem as they are not degraded by biological systems, but some microorganisms and plants can accumulate metals in a process known as Bioaccumulation
• Organic wastes can be treated and degraded biologically both aerobically and anaerobically
• Certain substances foreign to an entire biological system, like pollutants such as dioxins and polychlorinated biphenyls, which are not easily degraded, are known as Xenobiotics
• Recalcitrants are compounds that resist any degradation, whether chemical or biological
• The degradation of synthetic compounds depends on their structure, solubility, and toxicity
• Compounds with low solubility in water generally have greater solubility in cellular lipids and are accumulated in fatty tissues of the organism, leading to bioaccumulation
• As synthetic compounds become more water-soluble, they are accumulate likely to be accumulated, posing a greater toxic potential especially if they enter the food chain
• Organic compounds containing halogens are slow to degrade
• Industrial wastes often contain petrochemicals, oil, petrol, and diesel, leading to pollution through disposal, tank leakage, and marine spills
• Many naturally occurring microbes in the environment can degrade these synthetic compounds
• Biodegradation outcomes and consequences:

  • Xenobiotic pollutant may be mineralized (completely oxidized to carbon dioxide)
  • Transformed to another compound that may be toxic or nontoxic
  • Accumulated within an organism
  • Polymerized
  • Get bound to natural materials in soils, sediments or water
  • More than one of these processes may occur for a single pollutant at the same time
• Bioremediation can be applied to an environmental problem in various ways:

  • Above ground bioreactors
  • Solid phase treatment
  • Composting
  • Landfarming
  • Insitu treatment
• Above ground bioreactors are used to treat liquids (e.g., industrial process streams, pumped groundwater), vapors (e.g., solvents vented from contaminated subsurface environments, factory air), or solids in a slurry phase (e.g., excavated soils, sludges or sediments, plant materials)
• Above ground bioreactors may use:

  • Suspended microorganisms or adsorbed biofilm, singly or in combination
  • Native microbial cultures isolated from appropriate environments
  • Genetically engineered microorganisms (GEMS) designed specifically for the problem
• Microorganisms in above ground bioreactors may operate with or without the addition of oxygen or other electron acceptors (nitrates, CO2, sulfate, oxidized metals) and nutrient feeds (nitrogen, phosphorus, trace minerals, co-substrates)
• b. Solid phase treatments: This usually involves placing soils within some type of containment system, eg: lined pit with leachate collection and/or volatile compound entrapment equipment, and then percolating water and nutrients through the pile. Oxygen may or may not be supplied, depending on the bioremedial process being encouraged or supported. Inoculum may or may not be added, depending on whether or not an indigenous microbial population can be stimulated to remove the target pollutant(s).
• c. Composting: It is a variation of solid phase treatment that involves adding large amounts of readily degradable organic matter to contaminated material, followed by incubation, usually aerobic, lasting several weeks or months. Adjusting the carbon: nitrogen ratio needs particular attention, also the need for turning the piles frequently makes the process labor intensive.
• d. Landfarming: Contaminated soils, sludges or sediments are spread on fields and cultivated in much the same manner as a farmer might plow and fertilize agricultural land. Most inexpensive and effective treatment for petroleum contaminated soils. It is a technique used for easily biodegradable chemicals. There could raise a problem for leaching of chemicals to groundwaters.
• e. Insitu bioremediation: Most insitu processes involve the stimulation of indigenous microbial populations so that they become metabolically active and degrade the contaminants of concern.
• Bioventing is becoming an attractive option for insitu biodegradation of readily degradable pollutants like petroleum hydrocarbons. Bioventing involves the forced movement of air through the contaminated sites. When oxygen is provided as a terminal electron acceptor, indigenous microorganisms multiply at the expense of the carbon present in the contaminating material. The goal is to provide sufficient oxygen to allow degradation of the pollutants to proceed to completion, without vaporizing contaminants to the surface