Kadar Pigmen Klorofil dan Karotenoid pada Nannochloropsis sp. dengan Perlakuan Penyinaran Ultraviolet

Abstract

Nannochloropsis sp. merupakan fitoplankton dengan kemampuan memproduksi pigmen klorofil-a, b, dan karotenoid yang berperan dalam fotosintesis. Produksi pigmen Nannochloropsis sp. dipengaruhi utama oleh faktor cahaya. Pemberian sinar UV berpotensi memberikan rangsangan terhadap fitoplankton pada pertumbuhan sel dan produksi pigmen. Penelitian ini bertujuan untuk menentukan upaya yang sesuai untuk peningkatan kadar klorofil dan karotenoid Nannochloropsis sp. menggunakan perlakuan sinar UV.  Rancangan penelitian melalui Rancangan Acak Lengkap (RAL) dengan tiga kali pengulangan. Perlakuan sinar UV yang diberikan meliputi 4 kelompok yaitu; 0 (kontrol), 10, 20, dan 30 menit. Pengamatan kualitas air pada media dan perhitungan kepadatan sel dilakukan setiap hari hingga masing-masing kultur mencapai fase stasioner untuk pemanenan. Kadar pigmen klorofil-a, b, dan karotenoid ditentukan menggunakan metode spektrofotometri dan diuji secara statistika melalui ANOVA One Way. Hasil penelitian didapatkan bahwa kepadatan sel tertinggi terdapat pada kelompok pemberian sinar UV 10 menit sebesar 1017,714x105 sel/mL pada fase stasioner hari ke-24. Kadar pigmen klorofil-a tertinggi pada kelompok sinar UV 20 menit, yaitu sebesar 108,46 µg/g berat basah, klorofil-b tertinggi pada kelompok UV 30 menit, yaitu sebesar 32,93 µg/g berat basah, dan karotenoid tertinggi pada kelompok UV 10 menit, yaitu sebesar 147,88 µg/g berat basah. Namun, berdasarkan uji statistika pemberian sinar UV sampai 30 menit tidak memberi pengaruh nyata (p≥0,05) terhadap kadar klorofil-a,b, dan karotenoid yang dihasilkan.  Nannochloropsis sp. is a phytoplankton with the ability to produce chlorophyll-a, b, and carotenoid pigments that are useful for photosynthesis. Pigment production of Nannochloropsis sp. is influenced mainly by the light factor. The treatment of UV light has the potential to stimulate phytoplankton cell growth and pigment production. This study aims to determine the appropriate efforts to increase levels of chlorophyll and carotenoids Nannochloropsis sp. using UV light treatment. The research design was through a completely randomized design (CRD) with three repetitions. UV light treatment given includes 4 levels, namely; 0 (control), 10, 20, and 30 minutes. Observation of media water quality and cell density calculations were carried out every day until each culture reached a stationary phase for harvesting. The levels of chlorophyll-a, b, and carotenoid pigments were determined using the spectrophotometric method and statistically tested through One Way ANOVA. The results showed that the highest cell density was found at the 10-minute UV light level of 1017,714x105 cells/mL on the stationary phase on the 24th day. The highest levels of chlorophyll-a were at the UV light level of 20 minutes, which was 108.46 µg/g wet weight, the highest chlorophyll-b was at the UV level of 30 minutes, which was 32.93 µg/g  wet weight, and the highest carotenoids were at the UV 10 level. minutes, which is 147.88 µg/g wet weight. However, based on statistical tests, UV light up to 30 minutes did not have a significant effect (p≥0.05) on the levels of chlorophyll-a, b, and carotenoids produced.