BioremediasiKuliah 2

Semester 2 – 2012/2013 Disusun OlehRenni Suhardi

Environmental Fate of

Organic Pollutans

How the synthetic organic compounds How the synthetic organic compounds How the synthetic organic compounds How the synthetic organic compounds

are enters the environmentare enters the environmentare enters the environmentare enters the environment

Because of the following reasons they enters the environment primarily" Dispersive use " Losses of during production,"Accidental splits etc.

Exposure Pathway

When material is released into the environment, its fate depends upon :�a whole range of physiochemical processes

�its interaction with living organisms.

POLLUTANTS� Bio-degradable

petroleum products (gas, diesel, fuel oil) •crude oil compounds (benzene, toluene, xylene, naphthalene) •some pesticides (malathion) •some industrial solvents •coal compounds (phenols, cyanide in coal tars and coke waste)

� Partially degradable / Persistent

TCE (trichlorethylene) threat to ground water •PCE (perchlorethlene) dry cleaning solvent •PCB’s (have been degraded in labs, but not in field work) •Arsenic, Chromium, Selenium

� Not degradable / Recalcitrant

Uranium •Mercury •DDT

PersistentPersistentPersistentPersistent� All waste is potentially harmful, but some may be more harmful than others

� wastes that accumulate in the environment, breaking down over a long period of time (slowly) or not breaking down at all

� ex. plastics, radioactive compounds, heavy metals like lead and mercury

Biodegradable or Non-Persistent� wastes that may be broken down into simple non-polluting compounds by naturally-occurring chemical reactions (or by bacteria and other microorganisms)

� ex. organic compounds, biological waste compounds, wood, paper, etc.

Biodegradation� breaking down or altering toxic compounds to biomass and compounds that are less or non-toxic, less complex compounds, or by immobilizing toxic contaminants to retard their movement into non-contaminated areas, and ultimately to water, carbon dioxide and the oxides or mineral salts of other elements presents.

Two extents of biodegradation of a

substance:

� Primary biodegradation - modification of some physical and chemical properties of the substance caused by activity of micro-organisms.

� Ultimate biodegradation - total utilization of the substance resulted in its conversion into carbon dioxide (CO2) or methane (CH4), water (H2O), mineral salts and microbial cellular constituents (biomass).

Environmental persistence The ability of certain chemical substances to persist in the environment

Recalcitrant Compounds� The compounds are highly resistant to biodegradation is known as recalcitrant compounds.

.

� And therefore are treated using microbes to help with the process of degrading the recalcitrant compounds into smaller, more manageable compounds.

Xenobiotic compounds� toxic to life and are also often hard for microorganisms to metabolize � because they contain molecular arrangements that not normally encountered in nature.

� Thus, many of these compounds can accumulate in the environment and continue to be a hazard for many years.

Fate of organic compounds in the uptake into the Fate of organic compounds in the uptake into the Fate of organic compounds in the uptake into the Fate of organic compounds in the uptake into the

cells and cells and cells and cells and degradation, assimilation degradation, assimilation degradation, assimilation degradation, assimilation and and and and

mineralizationmineralizationmineralizationmineralization

MineralizationMineralizationMineralizationMineralization

� The complete breakdown of an organic compound into inorganic components

Biotransformation� Metabolic modification of the molecular structure of a compound, resulting in the loss or alteration of some characteristic properties of the original compound, with no (or minor) loss of molecular complexity

� Effect of biotransformation:� Solubility

� Mobility in the environment

� Toxocity of organic compounds

Pentachlorophenol to Pentachloroanisole

(detoxicifation)

Co-metabolism� Growth of microbe on one compound that transform a contaminating chemical that cannot be used as carbon and energy source

� Result in � a minor modification of the molecule

� Incomplete or complete degradation

Cometabolism

Biodegradation ProductIn comparison to the original compound

� Less harmful

� As hazardous

� More hazardous : tetracholoroethene/trichloroethene to vinyl chloride (carcinogen)

Chloroethene Biodegradation Pathways

Oil Waste

The tests determine the rate of the

biodegradation

� Readily biodegradable - at least 60-70% (depending on the test type) of the sample oil is degraded.

� Inherently biodegradable - 20-60% of the sample oil is degraded.

� Persistent - less than 20% of the sample oil is degraded.

Biodegradability of some lubricantsBiodegradability of some lubricantsBiodegradability of some lubricantsBiodegradability of some lubricants

Lubricant Biodegradability, %

Mineral oil 15-35

White oil (highly refined mineral oil) 25-45

Vegetable lubricants 70-100

Polyalphaoleins (PAO) 5-30

Polyether 0-25

Polyisobutylene (PIB) 0-25

Phthalate & Trimellitate Esters 5-80

Polyol esters & Diesters 55-100

Total Petroleum Hydrocarbon

� Petroleum crude oils can be broadly divided into paraffinic, asphaltic, and mixed crude oils (WHO 1982).

� Paraffinic crude oils are composed of aliphatic hydrocarbons

(paraffins), paraffin wax (longer chain aliphatics), and high grade oils .

� Naphtha is the lightest of the paraffin fraction, followed by kerosene fractions.

� Asphaltic crude oils contain larger concentrations of cycloaliphatics and high viscosity lubricating oils.

Toxicology Toxicology Toxicology Toxicology � Petroleum hydrocarbon fuels and oils are mainly composed of aliphatic and aromatic hydrocarbon compounds.

� Petroleum aromatic hydrocarbons generally appear to be more toxic than petroleum aliphatic compounds

� TPH is defined as the measurable amount of petroleum-based hydrocarbon in an environmental media

� TPH clean-up level of 10,000 mg/kg (1% by weight)

API Gravity

Anthracene Pathway

CO2

Conclusion 1� Biodegradation is an important process that can result in the loss or transformation of a chemical substance in the environment.

Conclusion 2� ‘Biodegradable means that a material has the proven capability to decompose in the most common environment where the material is disposed of within 3 years through natural biological processes into nontoxic carbonaceous soil, water, carbon dioxide or methane.’

Conclusion 3

When compounds are persistent in the environment?

Approach to proceed their biodegradation through multiple steps utilizing different enzyme systems or different microbial populations.

Referensi:� Bioremediation of Relcalcitrant Compounds. JEFFREY W. TALLEY. Taylor and Francis

Publisher 2005

� Manuel J Go´mez1, Florencio Pazos2,3, Francisco J Guijarro2, Vı´ctor de Lorenzo2,* and Alfonso Valencia4. (2007) The environmental fate of organic pollutants through the global microbial metabolism, Molecular Systems Biology 3; Article number 114

� S Fetzner (2005) Biodegradation of Xenobiotics. Biotechnology Vol X