Environmental Microorganisms

Environmental Engineering Lab

레 넉 투안

Contents

• General classification

• Microorganisms in the surface waters and wastewaters

• Applications of Microorganisms to environmental treatment

Overview: Classification

Phylogenetic tree of life

Classification by molecular and cellularrelationships:

BacteriaArchaea

Eukarya

Prokaryote

Eukaryote

Internal structure of microbial cells. (a) Diagram of a prokaryote.(b) Diagram of a eukaryote.

Cell structure

Double helix structure of DNA

Nucleic acids

Base-pairing in DNA

Microorganisms in their natural environment

They don’t live in pure cultures. They live in communities.

Their activities can greatly affect (change) the chemical and physical properties of their habitats, e.g. the removal of nutrients and the excretion of waste products.

Populations in microbial communities can interact in various ways -harmful and/or beneficial.

Role of microorganisms in geochemical nutrient cyclesRole of microorganisms in geochemical nutrient cycles

• Microorganisms play a role as:•PRIMARY PRODUCERS •BIODEGRADERS AND CONSUMERS

• Critical role in cycles of many elements;• Carbon and and Oxygen cycle • Nitrogen cycle• Sulfur cycle• Phosphorus cycle

• Microorganisms play a role as:•PRIMARY PRODUCERS •BIODEGRADERS AND CONSUMERS

• Critical role in cycles of many elements;• Carbon and and Oxygen cycle • Nitrogen cycle• Sulfur cycle• Phosphorus cycle

How do they grow: requirements?How do they grow: requirements?

• Nutrients• Carbon, Nitrogen, Phosphorus, Sulfur• Many chemicals supply these• Micronutrients/ trace metals/ vitamins

• Electron acceptors - usually O2

• Converts / burns carbon substrate to CO2

Energy and biomass * GROWTH

• Nutrients• Carbon, Nitrogen, Phosphorus, Sulfur• Many chemicals supply these• Micronutrients/ trace metals/ vitamins

• Electron acceptors - usually O2

• Converts / burns carbon substrate to CO2

Energy and biomass * GROWTH

Wastewater treatment: Wastewater treatment: principles

SINGLESINGLE BACTERIUMBACTERIUM

2.0m

ORGANIC POLLUTANTORGANIC POLLUTANTAND NUTRIENTSAND NUTRIENTS(C,P,N,O,Fe,S……)(C,P,N,O,Fe,S……)

GROWTH - CELL DIVISIONGROWTH - CELL DIVISIONINCREASE IN BIOMASSINCREASE IN BIOMASS

COCO22

evolvedevolved

OO22 consumption consumption

Controlled release of energyControlled release of energySlow Burning!Slow Burning!

Somes microorganisms found in natural waters, wastewaters, and wastewater treatment processes

Bacteria

Algae

ProtozoaArchaea

Fungi Virus

Pathogens and parasites found in domestic wastewater

The three categories of pathogens encountered in the environment are (Leclerc et al., 2002):

• Bacterial pathogens: Some of these pathogens (e.g., Salmonella, Shigella) are enteric bacteria. Others (e.g., Legionella, Mycobacterium avium, Aeromonas) are indigenous aquatic bacteria.

• Viral pathogens: These are also released into aquatic environments but are unable to multiply outside their host cells. Their infective dose is generally lower than for bacterial pathogens.

• Protozoan parasites: These are released into aquatic environments as cysts or oocysts, which are quite resistant to environmental stress and to disinfection, and do not multiply outside their hosts.

Eg: Giardia lamblia Balantidium coli…

Indicator microorganisms

The total coliform: group belongs to the family enterobacteriaceae and includes the aerobic and facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria that ferment lactose with gas production within 48 hours at 35C. This group includes Escherichia coli, Enterobacter, Klebsiella, and Citrobacter. These coliforms are discharged in high numbers in human and animal feces, but not all of them are of fecal origin.

Fecal Coliforms: Fecal coliforms or thermotolerant coliforms include all coliforms that can ferment lactose at 44.5oC. The fecal coliform group comprises bacteria such as Escherichia coli or Klebsiella pneumonae. The presence of fecal coliforms indicates the presence of fecal material from warm-blooded animals.

Escherichia Coli: Several strains of E. coli, many of which are harmless, are found in the gastrointestinal tract of humans and warm-blooded animals. There are several categories of E. coli strains, however, that bear virulence factors and cause diarrhea.

• Water quality can be impaired by natural elements normally found in soil and rock. These natural elements can be considered contaminates that can harm humans:

- Metals: arsenic, mercury and lead

- Turbidity: suspended particles of clay soil

- Microorganisms: parasites, bacteria, protozoa and toxic blue-green algae.

• Faecal matter from confined animal facilities and feedlots, as well as from animals walking or defecting in streams, can contaminate water with bacteria such as E. coli or microbial pathogens (Cryptosporidium)

• Factory farming of hogs or cattle, where liquid waste is deliberately forced into the ground through boreholes can lead to water contamination.

Rivers: problems for surface water resource

Municipal wastewater effluents.

• Municipal wastewater effluents or sewage treatment plants are designed to treat waste that is discharged by residents, businesses and industries.

• The quality of water that leaves a treatment plant depends on a variety of factors, such as the type and efficiency of the treatment and disinfection processes used, as well as the quantity and types of wastes received.

• Since treatment processes differ so greatly, municipal wastewater effluents can consist of residues of human waste, solids and debris, nutrients, pathogens, toxics, endocrine disrupting substances, unmetabolized pharmaceuticals, ingredients from household and personal care products, and potentially toxic chemicals and contaminants.

Eutrophication of Surface Waters.c

Natural process in which surface waters receive inputs of nitrates an

d phosphates resulting in overnourishment of aquatic ecosystems

(Algae bloom, anaerobic surface water)

• Phosphorus is a key of nutrient responsible for eutrophication

The bright green colour results from bluegreen algae (Cyanobacteria), which are growing on phosphorus added to the near side of the curtain

Microorganisms and Nitrogen

• Nitrogen fixation

Microorganisms and Nitrogen…

• Nitrogen assimilation

Cells convert NO3 or NH4 to proteins and grow until nitrogen becomes limiting. For each 100 units of carbon assimilated, cells need approximately 10 units of nitrogen (C/N ratio = 10).

• Nitrogen Mineralization

Nitrosomonas, nitrobacter

Nitrogen removal

Phosphorus (P)

• Organic phosphorus: foodstuff, toilet wastes, animal wastes…;

• Orthophosphate (PO4-P): fertilizer, products of phosphorus mineralization;

• Polyphosphate: detergents.

Phosphorus removal

1. Chemical precipitation, which is controlled by pH and cations such as

Ca, Fe and Al…

Problems: saturation, clogging.

2. Biological phosphorus removal

• Phosphorus assimilation by wastewater microorganisms;

• Enhanced biological phosphorus removal (EBPR);

• Microorganism-mediated enhanced chemical precipitation.

Enhanced biological phosphorus removal (EBPR)

Pi release and uptake by a laboratory anaerobic–aerobic activated sludge. From Hiraishi et al. (1989).

Several microorganisms, called poly P bacteria or polyphosphate accumulating organisms (PAOs), have the ability to accumulate phosphorus in excess of the normal cell requirement, which is around 1–3 percent of the cell dry weight.

(eg., Acinetobacter, Pseudomonas, Aeromonas, Moraxella, Klebsiella, Enterobacter, Tetrasphaera spp.)

Poly PTCA cycle

Glycogen+ ATP

o-PO4

Poly PGlycogen

ATP

O2CO2 + H2O

Anaerobiccondition

Aerobiccondition

PHA

PHA

Volatide Fatty Acid (acetate…)

Biochemical model (Mino et al., 1987)

Cell growth

- Under the anaerobic condition, PAO uptake Volatile fatty acids (VFAs) mainly acetate and stored in side the cells as PHA. The energy for this process is obtained form degradation of polyphosphate (polyP) and glysosis of glycogen. The degradation of poly P results in the release orthophosphate in the liquid.

- Under the aerobic zone, in the absence of any organic compounds, PHA is metabolized producing energy and carbon sources. The energy is used by PAOs to uptake orthophosphate in order to recover and increase the polyP pool in the cell and to form glycogen

Polyhydroxyalkanotes (PHAs) are biodegradable polymers synthesized by a number of microorganisms when the essential growth nutrients is limited.

Enhanced biological phosphorus removal (EBPR)…

• Glycogen accumulating organisms (GAOs), are also part of the EBPR micr

obial assemblages. (e.g., Candidatus, Competibacter, phosphatis). Althou

gh GAOs carry out carbon transformations similar to those of PAOs, they

do not take up or release phosphorus (Blackall et al., 2002).

• For the successful operation of the EBPR process one must create conditi

ons for the predominance of PAOs over GAOs. One such condition is the

operation of the EBPR process at pH higher than 7 (Filipe et al., 2001) sin

ce GAOs predominate at lower pHs. Low temperature is another factor co

ntrolling the predominance of PAOs over GAOs. The psychrophilic PAOs

are generally favored at low temperatures, leading to an increase in EBPR

efficiency (Erdal et al., 2003).

Enhanced biological phosphorus removal (EBPR)…

Biological waste-water treatment: The activated sludge process.Biological waste-water treatment: The activated sludge process.

Sludge Microbiology

• Bacteria: Zooglea, Pseudomonas, Flavobacterium, Alcaligenes, Achromobacter, Corynebacterium, Comomonas, Brevibacterium, Acinetobacter, Bacillus…

• Fungi: Geotrichum, Penicillium, Cephalosporium, Cladosporium, and Alternaria…

• Protozoa: Aequorea victoria, Aspidisca costata, Cryptosporium…

Products from Microorganisms: Overview of range of examples.Products from Microorganisms: Overview of range of examples.

• Various foods and drinks

• Enzymes for varied uses (GM enzymes); biocatalysts

• Engineered proteins ( antibodies )

• Vaccines and antibiotics (secondary metabolites)

• Primary metabolites and bulk chemicals (amino acids (glutamic acid) and or

ganic acids (acetic acid)

• Pharmaceuticals and novel chiral chemicals

• Recovery of metals in bioleaching

• Biosensors (use of enzymes to specifically detect chemicals in medical)

• Various foods and drinks

• Enzymes for varied uses (GM enzymes); biocatalysts

• Engineered proteins ( antibodies )

• Vaccines and antibiotics (secondary metabolites)

• Primary metabolites and bulk chemicals (amino acids (glutamic acid) and or

ganic acids (acetic acid)

• Pharmaceuticals and novel chiral chemicals

• Recovery of metals in bioleaching

• Biosensors (use of enzymes to specifically detect chemicals in medical)

Thank you for your attention!