MOLECULAR CHARACTERIZATION OF A GREEN ALGAE ISOLATE BY 16S rRNA IN IMPROVEMENT OF CAROTENOID PRODUCTION

Abstract

Sintesis karotenoid alami belum pernah melebihi produk sintetik pada skala komersial. Kurangnya pemahaman mengenai aspek mikrobiologis dan ekofisiologis isolat penghasil karotenoid seringkali menyebabkan terjadinya kesalahan penamaan spesies. Sam isolat lokal alga hijau dan Perairan Jepara yang digunakan sebagai pakan alami sumber karotenoid hewan-hewan perikanan, pada mulanya dianggap sebagai Dunaliella. Penamaan Dunaliella hanya dilakukan berdasarkan pengamatan mikrobiologis dan ekofisiologis yang kurang lengkap. Tujuan utama penelitian mi adalah menentukan spesies sam isolat lokal alga hijau secara molekuler menggunakan 16S rDNA untuk mendeteksi jalur biosintesis karotenoid yang digunakan. Urutan basa 16SrRNA yang diperoleh dianalisis menggunakan Multiple Alignment Analysis dan analisis filogenetik melalui program ClustalX ClustaiW, GeneDoc, Phylip dan NjPlot. Hasil penelitian memperlihatkan bahwa Isolat alga hijau menunjukkan similaritas yang tinggi dengan anggota-anggota Sianobakteria. Keserupaan tertinggi dimiliki dengan Cyanobacterium sp. MBIC 1021 sebesar 99 %, diikuti Synechoystis PCC6308 sebesar 95 %. Hasil analisis similaritas dan filogenetik memperlihatkan peluang bahwa Isolat alga hijau mengikuti jalur baru non-mevalonat dalam biosintesis karotenoidnya. Abstract Carotenoids production levels are not yet competitive with carotenoid levels presently produced by fermentation, synthesis and isolation. An attempt to optimize carotenoid production from local isolate of green algae from BBAP Jepara has faced several problems, primarily related to the microbiological and eco-physiological characteristic which affecting growth that have not sufficiently been understood. A misnamed of species also have arisen due to wrong characterization. One local isolate of Dunaliella species from BBAP Jepara was found potentially useful as source of carotenoids in food additives or as food supplement in fish farming. The present study aimed to characterize the species of green algae isolate from Jepara waters based on molecular techniques using 16S rRNA approach to detect its carotenoid biosynthetic pathway. Similarities analysis and phylogenetic relationship of 16S rRNA sequence was analyzing with Multiple Alignment Analysis by ClustalX ClustalW, GeneDoc, Phylip and NjPlot Programs. Molecular analysis showed close relationship among isolate of green algae and Cyanobacteria with 99 % similarity with Cyanobacterium sp. MBIC 1021 and 95 % similarity with Synechocysti.s PCC3O8. The result of this analysis indicated possibilities that a green algae isolate following the new non-mevalonate pathway for its catotenoid biosynthetics. Keywords A green algae isolate, Dunaliella, 16S rRNA, Cyanobacteria