Penapisan Mikroalga Penghasil Karotenoid serta Studi Pengaruh Stres Nitrogen dan Fosfor terhadap Produksi B-Karoten pada Mikroalga Oocystis sp.

Abstract

Abstrakb-karoten merupakan karotenoid yang bermanfaat sebagai antioksidan. Penelitian ini bertujuan menapis mikroalga yang berpotensi  mengandung karotenoid tinggi dan mempelajari pengaruh nitrogen dan fosfor terhadap produktivitas biomassa, kandungan pigmen fotosintesis dan b-karoten, pada mikroalga yang diisolasi dari perairan Danau Atas, Sumatra Barat. Penapisan mikroalga penghasil karotenoid dilakukan  dengan memberikan  paparan UV-A 326 nm terhadap kultur campuran mikroalga. Hasil penelitian menunjukkan bahwa 5 dari 18 spesies mampu bertahan pada proses penapisan. Pengaruh 9 jenis medium pertumbuhan dengan kriteria: tanpa NaNO3, 3x NaNO3, 5x NaNO3, 10x NaNO3, Bold Basalt Medium (BBM) normal (kontrol), tanpa KH2PO4, 3x KH2PO4, 5x KH2PO4,dan10x KH2PO4 terhadap mikroalga terpilih (Oocystis sp.) diamati. Hasil menunjukkan kandungan b-karoten tertinggi  ditemukan pada perlakuan 5x KH2PO4  yaitu sebesar 0,22 % dari berat kering mikroalga, dengan produktivitas biomassa 0,0015 g/mL/hari, serta kandungan klorofil a, klorofil b dan karotenoid total yaitu 7,15 µg/mL, 0,81 µg/mL dan 6,67 µg/mL. Berdasarkan penelitian ini dapat disimpulkan medium pertumbuhan dengan kandungan 5x KH2PO4 merupakan medium yang cocok bagi pertumbuhan Oocystis sp. untuk mendapatkan biomassa dengan kandungan b-karoten dan karotenoid tinggi tanpa harus menurunkan produktivitas biomassanya. Screening of Carotenoid Producing Microalgae and Study of the Effect of Nitrogen and Phosphorus Stress on the Production of b-Carotene in Microalgae Oocystis sp.Abstractb-carotene is a carotenoid that is useful as an antioxidant. Present study aims to screening high microalgae which contain carotenoids from water of Danau Atas lake (West Sumatra Province), and study the effect of nitrogen and phosphorus on biomass productivity, photosynthetic and b-carotene pigment content. Screening of carotenoid-producing microalgae was carried out by exposing UV-A 326 nm to mixed microalgae cultures. The results showed that 5 of the 18 species were able to survive in the screening process. The effect of growth medium, i.e. without NaNO3, 3x NaNO3, 5x NaNO3, 10x NaNO3, normal Bold Basalt Medium (BBM) (control), without KH2PO4, 3x KH2PO4, 5x KH2PO4, and 10x KH2PO4 on of selected microalgae (Oocystis sp.) was carried out. The result showed that the highest content of b-carotene of Oocystis sp. was obtained with 5x KH2PO4 which was 0.22% of the dry weight of biomass. Biomass productivity was 0.0015 g/mL/day and the chlorophyll a, chlorophyll b and total carotenoids contents were 7.15 µg/mL, 0.81 µg/mL and 6.67 µg/mL, respectively. Based on this research, 5x KH2PO4 can be concluded as a suitable medium for Oocystis sp. to obtained high b -carotene and carotenoid of Oocystis sp. without  reducing biomass productivity.