Which of the following is edible, non-toxic, fast growing cyanobacterium?

Options

A. Microcystis
B. Anabaena flos-aquae
C. Spirulina
D. Aphanizomenon flos-aquae

Answer

To determine which of the given cyanobacteria is edible, non-toxic, and fast-growing, let's analyze each option step by step.

### Step 1: Analyze Microcystis
- **Description**: Microcystis is a genus of freshwater cyanobacteria.
- **Characteristics**: Known for causing algal blooms.
- **Toxicity**: Produces various toxins, including neurotoxins and hepatotoxins.
- **Conclusion**: Microcystis is highly toxic and not edible.

**Hint**: Look for characteristics that indicate toxicity and potential harm to humans and animals.

### Step 2: Analyze Anabaena
- **Description**: Anabaena is a filamentous genus of cyanobacteria.
- **Characteristics**: Known for nitrogen fixation.
- **Toxicity**: Produces neurotoxins, making it harmful to farm animals and pets.
- **Conclusion**: Anabaena is also toxic and not suitable for consumption.

**Hint**: Consider whether the organism is known for producing toxins that affect health.

### Step 3: Analyze Spirulina
- **Description**: Spirulina is a biomass of cyanobacteria.
- **Characteristics**: Rich in dietary nutrients and used as a dietary supplement.
- **Toxicity**: Completely non-toxic and safe for human consumption.
- **Conclusion**: Spirulina is edible, non-toxic, and fast-growing.

**Hint**: Check if the organism is used in dietary supplements or has health benefits.

### Step 4: Analyze Aphanizomenon
- **Description**: Aphanizomenon is another genus of cyanobacteria.
- **Characteristics**: Can exist in both toxic and non-toxic forms.
- **Toxicity**: Produces hepatotoxins and neurotoxins similar to Microcystis.
- **Conclusion**: Aphanizomenon is potentially toxic and not reliably safe for consumption.

**Hint**: Determine if the organism has both toxic and non-toxic forms, which complicates its edibility.

### Final Conclusion
After analyzing all the options, the only cyanobacterium that is edible, non-toxic, and fast-growing is **Spirulina**.

### Summary of the Correct Answer
- **Correct Answer**: Spirulina