Growth and proximate composition of Nannochloropsis sp. cultured using different media in indoor and outdoor condition

Abstract

Nannochloropsis sp. was widely used in aquaculture as it has a great source of protein, lipid and carbohydrate. Microalgae's major applications for aquaculture are related to nutrition, being used fresh as a sole component, as a food additive to basic nutrients, for coloring the flesh of salmonids and for other biological activities. Study on Nannochloropsis sp .. was conducted to determine the growth and the proximate composition of Nannochloropsis sp. cultured using different media in indoor and outdoor culture condition. This study was conducted at Universiti Malaysia Terengganu. Marine rnicroalgae, Nannochloropsis sp., was collected and cultured in two different media - Conway and KW2 l; and two different culture conditions - indoor and outdoor. The growth and proximate composition - protein, lipid and carbohydrate; of all culture treatments were determined. Nannochloropsis sp. was grown best in both culture media even though growth in KW2 l was slightly higher (P>0.05) when compared to Conway medium. Nannochloropsis sp. culture in indoor (laboratory) condition was significantly shown higher growth (P<0.05) when compared to the outdoor (natural) culture condition. The protein production seems to be significantly high (P>0.05) in KW21 culture medium (39.58% and 32.99% for indoor and outdoor respectively) when compared to Conway medium (26. 74% and 19.05% for indoor and outdoor respectively). However, rnicroalgae culture under indoor culture condition (26.74% and 39.58% for Conway and KW21 media respectively) has shown significantly high (P>0.05) percentage of protein as compared to outdoor condition (19.05% and 32.99% for Conway and KW21 media respectively). Lipid accumulation in Nannochloropsis sp. was significantly high (P>0.05) when cultured under indoor condition (27.2% and 25.6% for Conway and KW21 respectively) when compared to outdoor condition (18.13% and 12. 73% for Conway and KW21 respectively). The percentage (%) of carbohydrate in microalgae cultured in Conway medium for indoor condition (34.01 %) was slightly high (P<0.05) compared to outdoor condition (32.29%). All of the results obtained might be affected by some physical factors such as light intensity and temperature; as well as nutrient composition such as nitrogen, phosphate and trace metals. From the results obtain, we also can make a conclusion that Nannochloropsis sp. can grow best in both Conway and KW2 l media under indoor culture condition.