Can we make cities more sustainable by having living walls?

Methods

Summary

Why this cyanobacteria?

Cyanobacteria:

1. Synechocystis sp. PCC 6803:

• A well-studied photosynthetic cyanobacterium, it is efficient in capturing CO₂ and producing oxygen.

• Its adaptability to environmental changes and compatibility with genetic modifications makes it a versatile option.

• It can form biofilms, which are crucial for the structural stability of the paint.

1. Chroococcidiopsis cubana:

• Known for its high CO₂ absorption and resilience in fluctuating environmental conditions.

• It is ideal for systems requiring robust organisms capable of contributing to biofilm formation and water retention.

Algae:

We selected four promising algae to pair with the cyanobacteria:

1. Nannochloropsis gaditana: Exceptional at CO₂ absorption and tolerant to saline conditions.

2. Chlamydomonas reinhardtii: A genetically flexible alga with excellent adaptability.

3. Scenedesmus obliquus: Resilient and capable of forming strong biofilms, enhancing system stability.

4. Spirulina platensis: Robust, high-biomass-producing, and efficient in oxygen generation.

These organisms were chosen based on their efficiency, adaptability, and potential to complement the cyanobacteria in achieving our project objectives.

Objectives

1. Capture CO₂: Maximize the paint's ability to remove CO₂ from the atmosphere.

2. Produce Oxygen: Ensure high oxygen output through photosynthesis.

3. Absorb Moisture: Develop a system that can effectively capture and retain water from the ambient environment.

Experiments to Be Conducted

1. Cyanobacteria Alone:

• Evaluate Synechocystis sp. PCC 6803 and Chroococcidiopsis cubana independently to assess their individual capabilities.

1. Cyanobacteria-Algae Combinations:

• Pair each cyanobacteria with two selected algae to test compatibility and efficiency in meeting the objectives.

More potential considerations: 

Growth Mediam, Includes necessary nutrients and salts for algae cultivation.

Lighting And Aeration, LED grow lights and air pumps for maintaining optimal growth conditions.

Temperature Control, Costs depend on whether heating or cooling is needed.

Sterility, Costs rise for lab-grade work due to contamination prevention (e.g., laminar flow hoods, sterile consumables).

Quadrant of Responsibilities

Member	Cyanobacteria (Individual)	Combination 1	Combination 2
Atharva	Synechocystis sp. PCC 6803	Synechocystis sp. + Nannochloropsis gaditana	Chroococcidiopsis cubana + Scenedesmus obliquus
Begüm	Chroococcidiopsis cubana	Synechocystis sp. + Chlamydomonas reinhardtii	Chroococcidiopsis cubana + Spirulina platensis
Laksh	Synechocystis sp. PCC 6803	Synechocystis sp. + Scenedesmus obliquus	Chroococcidiopsis cubana + Nannochloropsis gaditana
Saryu	Chroococcidiopsis cubana	Synechocystis sp. + Spirulina platensis	Chroococcidiopsis cubana + Chlamydomonas reinhardtii
Palma	Comparison of both cyanobacteria	Synechocystis sp. + Nannochloropsis gaditana	Chroococcidiopsis cubana + Scenedesmus obliquus

Timeline and Weekly Organization

Week 1: Preparation (11–17 December)

• Activities:

• Secure laboratory space, cyanobacteria, algae, and materials.

• Set up growth media (BG-11 for cyanobacteria; saline or freshwater for algae).

• Stabilize cultures individually.

Week 2: Cyanobacteria Alone (18–24 December)

• Activities:

• Evaluate the growth, CO₂ capture, oxygen production, and water retention of Synechocystis sp. and Chroococcidiopsis cubana separately.

• Collect daily data.

Week 3: Combinations (25–31 December)

• Activities:

• Test assigned combinations of cyanobacteria and algae.

• Measure compatibility, biofilm formation, and efficiency in meeting objectives.

• Analyze results and compare combinations.

Data to Be Collected

Variable	How to Measure
pH (CO₂ Capture)	Measure pH daily using pH strips or a pH meter to track changes in the medium.
Oxygen Production	Use a dissolved oxygen sensor or chemical kits (e.g., Winkler method).
Growth (Density)	Observe visual color changes or measure optical density (OD) with a spectrophotometer (680 nm).
Water Retention	Weigh the absorbent material (e.g., gel silica or cotton) before and after the experiment to measure moisture.
Biofilm Formation	Observe and document film formation on surfaces; weigh surfaces if possible.

Laboratory Setup and Materials

Materials Needed:

• Cyanobacteria: Synechocystis sp. PCC 6803 and Chroococcidiopsis cubana.

• Algae: Nannochloropsis gaditana, Chlamydomonas reinhardtii, Scenedesmus obliquus, Spirulina platensis.

• Growth media: BG-11 for cyanobacteria; saline/freshwater media for algae.

• Equipment:

• pH meter or strips.

• Oxygen sensor or chemical kit.

• Spectrophotometer (if available).

• Balance for weighing.

• Containers: Petri dishes, flasks, or plates for biofilm formation.

• Absorbent materials: Gel silica, cotton, or other hydrophilic materials.

Lab Safety Tips:

1. Wear gloves and goggles when handling cultures and chemicals.

2. Sterilize all equipment before and after use to avoid contamination.

3. Dispose of biological waste properly according to local regulations.

Data Recording Template

Date	Test	pH Initial	pH Final	Oxygen (mg/L)	Growth Observation (OD or Color)	Water Retention (g)	Biofilm Observations
Day 1	Synechocystis + Nanno.
Day 2
...