Pengaruh Konsentrasi Pupuk Organik Cair Sargassum sp. terhadap Pertumbuhan Mikroalga Arthrospira sp.

Algifari Izzan Muska, Prof. Dr. Ir. Alim Isnansetyo, M.Sc.

2026 | Skripsi | BUDIDAYA PERIKANAN

Arthrospira sp. merupakan mikroalga bernilai ekonomis tinggi, namun budidayanya masih bergantung pada pupuk anorganik yang mahal dan berpotensi mencemari perairan. Penelitian ini bertujuan mengetahui pengaruh konsentrasi pupuk organik cair (POC) Sargassum sp. terhadap pertumbuhan dan kepadatan sel Arthrospira sp. serta menentukan dosis paling efektif. Penelitian menggunakan Rancangan Acak Lengkap dengan lima perlakuan dan tiga ulangan: P0 (kontrol negatif tanpa pupuk), P1 (kontrol positif, 100% media CFTR-1), serta P2, P3, dan P4 (media CFTR-1 dengan penambahan POC masing-masing 1%, 2,5%, dan 5%). POC dibuat melalui fermentasi anaerob selama 5 hari terhadap ampas Sargassum sp. sisa ekstraksi alginat dan fukoidan dengan penambahan molase dan probiotik. Arthrospira sp. dikultur selama 10 hari dan diamati kepadatan sel, laju pertumbuhan spesifik, doubling time, serta kualitas air. Data dianalisis dengan ANOVA dan uji Duncan atau Kruskal–Wallis (? = 0,05). POC mengandung nitrogen 1,82%, P?O? 0,95%, K?O 0,88%, serta fitohormon giberelin, IAA, zeatin, dan kinetin. Pemberian POC berpengaruh nyata (p < 0> 0,05) terhadap laju pertumbuhan spesifik maupun doubling time, dan kualitas air layak bagi pertumbuhan. Dosis POC 5% (P4) paling efektif pada rentang dosis yang diuji, sehingga berpotensi menjadi alternatif pupuk organik yang ekonomis dan ramah lingkungan.

Arthrospira sp. is a microalga of high economic value, yet its cultivation still depends on inorganic fertilizers that are costly and may pollute aquatic environments. This study aimed to determine the effect of Sargassum sp. liquid organic fertilizer (LOF) concentrations on the growth and cell density of Arthrospira sp. and to identify the most effective dose. A Completely Randomized Design was used with five treatments and three replications: P0 (negative control without fertilizer), P1 (positive control, 100?TR-1 medium), and P2, P3, and P4 (CFTR-1 medium with 1%, 2.5%, and 5% LOF, respectively). The LOF was produced by 5-day anaerobic fermentation of Sargassum sp. residue from alginate and fucoidan extraction, with molasses and probiotics added. Arthrospira sp. was cultured for 10 days, and cell density, specific growth rate, doubling time, and water quality were observed. Data were analyzed using ANOVA with Duncan's test or Kruskal–Wallis (? = 0.05). The LOF contained 1.82% nitrogen, 0.95% P?O?, 0.88% K?O, and the phytohormones gibberellin, IAA, zeatin, and kinetin. LOF significantly affected (p < 0> 0.05) on specific growth rate or doubling time, and water quality remained suitable for growth. A 5% LOF dose (P4) was the most effective within the tested range, indicating its potential as an economical and environmentally friendly alternative fertilizer.

Kata Kunci : Arthrospira sp., kepadatan sel, mikroalga, pupuk organik cair, Sargassum sp.