PRACTICAL 1: PREPARATION OF ALGAL CULTURE MEDIUM

INTRODUCTION

Algae are simple plants that differ from the microscopic (microalgae), to large seaweeds (macroalgae), such as giant kelp. Thus, cyanobacteria, (similar to bacteria, and formerly called “blue-green algae”) as well as green, brown and red algae were example of microalgae . However, Freshwater and marine fish culture has commonly used mircroalgae as food source by De Pauw, N. and G. Persoone, 1988.

Guillards’ F/2 Medium is one the example for algae culture medium. Guillard’s (F/2) Marine Water Enrichment Solution 50 X, is a concentration that can be diluted in filtered seawater to support reconstitution of Guillard’s (F/2) Marine Enrichment medium that make up of of major nutrients, trace metals and vitamins.  Guillard’s (F/2) Marine Enrichment medium commonly use for growing of coastal marine algae (diatoms).

The objective for this experiment is to prepare different medium for algal culture.

METHODOLOGY

Preparation of marine algal medium (Guillards’ F/2 medium)

Stocks	Per litre
NaNO3	75g
NaH2PO4.2H2O	5.65g
Trace elements (chelated)	Trace elements (chelated) consist of: NA2 EDTA = 4.16g FeCl3.6H2O = 3.15g CuSO4.5H2O = 0.01g ZnSO4.7H2O = 0.022g CoCl2.6H2O = 0.01g MnCl2.6H2O = 0.18g Na2Mo4.2H2O = 0.006g
Vitamin mix	Vitamin mix consist of: Cyanocobalamin (Vitamin B12) = 0.0005g Thiamine HCl (Vitamin B1) = 0.1g Biotin = 0.0005g

Ratio to produce 1L of F/2 medium :-

1mL NaNO₃ : 1mL NaH₂PO_4.2H₂O : 1mL trace elements : 1mL vitamin mix : 1L seawater

*Add while stirring, sterilise by autoclaving for 15 minutes at 15 psi and use when cooled to room temperature.

Preparation of F/2 + Si (Guillard’s medium for diatoms)

Stocks	Per litre
NaNO3	75g
NaH2PO4.2H2O	5.65g
Trace elements (chelated)	Trace elements (chelated) consist of: NA2 EDTA = 4.16g FeCl3.6H2O = 3.15g CuSO4.5H2O = 0.01g ZnSO4.7H2O = 0.022g CoCl2.6H2O = 0.01g MnCl2.6H2O = 0.18g Na2Mo4.2H2O = 0.006g
Vitamin mix	Vitamin mix consist of: Cyanocobalamin (Vitamin B12) = 0.0005g Thiamine HCl (Vitamin B1) = 0.1g Biotin = 0.0005g
Sodium metasilicate	Sodium metasilicate consist of: Na2SiO3.9H2O = 30.0g

Ratio to produce 1L of F/2 + Si (Guillard’s medium for diatoms) :-

1mL NaNO₃ : 1mL NaH₂PO_4.2H₂O : 1mL trace elements : 1mL vitamin mix : 1L filtered seawater : 1mL sodium metasilicate

*Add while stirring, sterilise by autoclaving for 15 minutes at 15 psi and use when cooled to room temperature.

RESULTS

Figure 1 Guillards' F/2 medium

Figure 2 Guillards' F/2 + Si (diatom purpose)

DISCUSSION

Guillard’s (F/2) Marine Water Enrichment Solution is a concentrate of major nutrients, trace metals and vitamins that can be diluted in filtered seawater to support reconstitution of Guillard’s (F/2) Marine Enrichment medium. It is a widely used enriched seawater medium for growing costal marine algae (diatoms). 

The preparation of the growth medium represents a considerable part of running cost in the process of fish culture (Zhang et al., 2001). It was reported that 30-40% (max.70%) of marine hatchery operating costs can be attributed to micro-algal culture (Heasman et al., 2001). Media for the culture of marine algae generally consist of a seawater base (natural or artificial) supplemented by analytical quality nutrients (Bold & Wynne, 1985). The term ‘nutrient’ is generally applied to any element or compound necessary for algal growth. Analytical grade nutrients chemicals (macronutrients and micronutrients) represent the most expensive constituents in any culture medium (Molina et al., 2003).

Furthermore, preparation of algal culture media is labor-intensive. Media are generally prepared from premixed stock solutions. Aliquots from these stocks are measured and added to a given volume of seawater. Micronutrient stock solution, however, must be prepared by combining aliquots of pre-prepared stock solutions and adding them to a given volume of distilled water, from which aliquots are measured and added to seawater, which may complicate the preparation processes. Precipitation of one or more component of the medium, may be encountered upon inaccurate preparation or combining the stock solutions of the culture medium (Harrison & Berges, 2005).

Additionally, the nutritional value of algae produced is high and comparable to that of conventional, analytical grade fertilizers such as F/2 (Valenzuela-Espinoza et al., 1999).  

CONCLUSION

This algal culture media are easy to be prepared one of simple medium for the algal growth as they require enough nutrient. For diatom such as Chaetoceros, they need nutrient for building their outer cell wall or known as silicate.

REFERENCES

1. http://allaboutalgae.com/what-are-algae/

2. El Nabris, K. J. A. (2012). Development of cheap and simple culture medium for the microalgae Nannochloropsis sp. based on agricultural grade fertilizers available in the local market of Gaza strip (Palestine). J Al Azhar Univ Gaza (Nat Sci), 14, 61-76.