Lesson 1 Slide

Environmental Biotechnology

🧩 Course Overview

Environmental Biotechnology focuses on how microbes sustain ecosystems and can be used for environmental recovery. Professors involved: Mads Albertsen, Per H. Nielsen, Jeppe L. Nielsen, Morten Dueholm, and others from Aalborg University + collaborators from Vienna, Delft, and Queensland.

You’ll learn how microbial communities drive water treatment, waste recovery, and sustainability.


🌍 Core Idea: Microbes Drive the Planet

  • Microbes control C, N, S, Fe, and P cycles, keeping life running.
  • Communal metabolism (whole-community cooperation) powers ecosystems far more than single-cell metabolism.
  • Biofilms = natural hubs of cooperation, enabling stable nutrient cycling and ecosystem balance.

🧫 Environmental Biotechnology Applications

Microbes = green engineers! 💧 Used in:

  • Water purification & disease control
  • Wastewater treatment
  • Biogas and bioenergy (methane, hydrogen)
  • Bioplastics (PHA) production
  • Phosphate recovery (EBPR systems)
  • Air purification and bioremediation

The aim: Transform waste into valuable resources (“circular economy”).


🧠 Key Theoretical Areas (Course Structure)

1️⃣ Introduction – microbial diversity, nutrient cycles 2️⃣ Biofilms, One Health, ARGs 3️⃣–4️⃣ Imaging methods (like FISH) 5️⃣–6️⃣ Community analysis (16S rRNA sequencing) 7️⃣–11️⃣ Applications – nutrient removal, pollutants, gut ecology, bioplastics, bioreactors


🧬 Microbial Diversity

Over 5–100 million bacterial species exist — but <10,000 are cultivated! 😱

  • Many remain uncultured → we use DNA-based tools to study them.
  • 16S rRNA gene acts like a fingerprint for bacterial ID.
  • Metagenomics lets us find who’s there and what they can do — even if they can’t be cultured.

🧪 Molecular Tools

To study uncultured communities:

  • Amplicon sequencing (16S) → identity
  • Metagenomics → potential function
  • Metatranscriptomics → active functions
  • Proteomics & metabolomics → proteins/metabolites actually produced
  • FISH microscopy → visualize where they are and what they do Together, these create Systems Microbiology — a complete ecosystem view 🧠🔬

⚡ Energy & Electron Flow

Life depends on redox reactions — microbes use different electron acceptors as energy sources. Example chain (“electron tower” 🧱): O₂ → NO₃⁻ → Mn⁴⁺ → Fe³⁺ → SO₄²⁻ → CO₂ As we move down, energy yield decreases → explains vertical structure in sediments and biofilms (oxygen at top, methanogens at bottom).


🌿 Microbial Conversions in Nature

Organic matter (CH₂O) → decomposed by microbes → CO₂, N₂, CH₄, etc. Depends on available acceptor:

  • Oxygen respiration (aerobic)
  • Denitrification (NO₃⁻ → N₂)
  • Sulfate reduction (SO₄²⁻ → H₂S)
  • Methanogenesis (CO₂ → CH₄)

Depth gradients determine which processes dominate 🌊


🧫 Microbial Ecosystems

Examples:

  • Lake
  • Wastewater plant
  • Gut
  • Biogas reactor

We study:

  • Inputs (substrates, microbes, temperature, salinity)
  • Outputs (biomass, gas, products)
  • Dynamics (stability, identity, interactions)

Key theories:

  • Ecophysiology
  • Metabolic models
  • Mass balances (C, N, P, energy)

🌡 Ecological Niches & Coexistence

Microbes coexist by occupying different niches — based on temperature, salinity, electron acceptors, or substrate preferences. Even tiny changes in substrate or oxygen allow many species to live together.


🌳 Diversity & Stability

  • Species richness = number of taxa
  • Functional redundancy = multiple species can perform the same role → gives stability (“insurance hypothesis”).
  • Resistance = ability to withstand disturbance
  • Resilience = ability to recover
  • Keystone species = small populations with huge influence (like sea stars in marine systems 🐚).

Diversity ensures stable functions — e.g., stable nitrification in wastewater systems requires multiple ammonia-oxidizers.


🔗 Microbial Interactions

Communities form networks of cooperation and competition:

  • Exchange metabolites
  • Cross-feed each other
  • Stabilize the ecosystem

Network analysis helps visualize these complex relationships 🕸️


💡 Applications in Wastewater & Resource Recovery

  • EBPR (Enhanced Biological Phosphorus Removal) 🧪
    • Key microbes: Candidatus Accumulibacter
    • They store phosphorus (PolyP) inside cells under alternating anaerobic/aerobic conditions.
  • PHA (Bioplastic) Production 🧴
    • Microbes use excess carbon to store Polyhydroxyalkanoates (PHAs).
    • Biodegradable and sustainable, but still costly to scale up.

🌎 Environmental Context

  • Linked to UN Sustainable Development Goals (SDGs).
  • Microbes help mitigate greenhouse gases, restore ecosystems, and recycle nutrients.
  • Related to planetary boundaries — microbial processes stabilize Earth’s biosphere.

🧠 Closing Concepts

  • The field integrates genomics, ecology, and biotechnology.
  • Environmental biotechnology = “microbiome stewardship” — managing microbial life to sustain the planet.
  • Future goal: develop new DNA-based tools to harness microbial power for global sustainability.

Quiz

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