Pengembangan kitosan sebagai absorben pengotor dalam aplikasi pemurnian agar dan karagenan

Abstract

Chitosan, a polymer of glucosamine is the largest polysaccharides after cellulose. A natural polymer chitosan has reactive ionic charge that has ability to bind and absorb other components of opposite charge as an absorbent. This research utilized chitosan in the process of seaweed purification . The purpose of this study were (1) To determine physical, chemical and microscopic characteristics of chitosan that will be developed as an absorbent (2) To test the ability of chitosan as an absorbent of heavy metals (Fe, Cu, Pb), pigments (carrot extract) and bacteria (E. coli ) (3) To apply chitosan to absorb impurity in the extraction of agar and carrageenan (4) To analyze the quality of agar and carrageenan produced from these methods. This study consisted of several stages which included: preparation, characterization and application phase. Preparation of chitosan production was conducted by modifying the process conditions, through 36 variations treatment NaOH concentrations (0.5-2N) and deproteinisation time (2-5 hours) and deacetylation with NaOH (1.5-6N), followed by quality analysis. The characterization phase involved determining the physical properties (size and viscosity), chemical (proximate and degree of deacetylation) and microscopic (morphology-surface pores) of chitosan.In addition the chitosan was tested to absorp metal (Fe, Cu, Pb), pigments (carrot extract) , and bacteria (Escherichia coli). Stage of the application included the use of chitosan product on agar and carrageenan extraction, the product was analysed using viscometer for viscosity, rheotex for gel strength, FTIR for functional group, SEM for morphology, Autosorp for pore distribution, ONPG: Ortho Nitro Phenil glycosides for bacteria and HPLC for analysis of the remaining components of impurities and main components/β-galactose. The selected results were obtained using chitosan with deacetylation degree 90%,which was made by using NaOH 1N for 4 hours of deproteinization and deacetylation time for 2 hours with 6N NaOH. The chitosan showed a physical-chemical characteristics as follows: 13.5% yield, colorless, transparent, N concentration of 4%, 0.2% mineral content, water content 10%, viscosity 247cPs at 1.5%, have amine functional groups detected at 1639cm-1 and hydroxy group at 3410 cm-1. SEM analysis showed the morphology of chitosancontaining pores and through autosorp analysis showed the distribution of pores with pore diameter variation between 37.2 Å up to 1,802,205 Å 0.1% chitosan has the ability to absorb 1% solution of (Fe 32%), Cu ( 26%), Pb (22%), carrot extract (100% w/v) by 50%, soft drinks pigment (55%) and 2% w/v biomass of E. coli (by 80.58%). 0.1% chitosan treatment for agar extraction as absorbent resulted agar quality (bacto agar as a comparison) as follows: TPC 1.25 x 102 CFU (2.04 x102 CFU of bacto agar), 0.1% sulphate content (0.3% of bacto agar), water content 21.1% (16, 9% of bacto agar), gel strength of 275.10 gF (350.15gF of bakto agar). The application to the extraction of carrageenan resulted : 12.40% sulphate content, gel strength of 80gF, 15% water concentration and viscosity of 26.4 cps. FTIR analysis showed seven functional groups (OH at 3000-3450 cm-1, CH at 2920 cm-1, amide at 1650 cm-1, sulphate ester at 1350-1355 cm-1, glycosidic bond at 1150 cm-1, 3.6 anhidro galaktan at 930 cm-1 and C2-OS and galaktan at 830 cm-1), while the sulphate functional groups was detected only at 1350 cm-1. The result of HPLC analysis showed the clear pick at 0.1% chitosan treatment. Thus the use of 0.1% chitosan was selected in the purification of agar and carrageenan as it is cheaper, simpler and non-chemical.

Kitosan adalah polimer glukosamin yang sangat banyak dialam setelah selulosa. Sebagai polimer alami kitosan mempunyai muatan ionik yang reaktif sehingga dapat mengikat dan mengabsorbsi komponen lain yang bermuatan berlawanan, oleh karena itu kitosan mempunyai kemampuan sebagai absorben. Kitosan dimanfaatkan sebagai absorben terhadap pengotor dalam proses pemurnian rumput laut sehingga dihasilkan produk (agar dan karagenan) yang bermutu baik. Tujuan dari penelitian ini adalah: (1) Menentukan karakteristik fisika, kimia dan mikroskopis kitosan yang akan dikembangkan sebagai absorben (2) Menguji kemampuan kitosan sebagai absorben logam berat (Fe Cu, Pb), pigmen ekstrak wortel dan bakteri Escherichia coli (E. coli) (3) Mengaplikasikan kitosan sebagai absorben terhadap pengotor pada ekstraksi agar dan karagenan (4) Menganalisis mutu agar dan karagenan yang dihasilkan dari metoda tersebut. Penelitian ini terdiri dari beberapa tahapan yang meliputi: tahap preparasi, tahap karakterisasi, dan tahap aplikasi. Tahap preparasi yaitu tahap produksi kitosan dengan memodifikasi kondisi proses, melalui 36 perlakuan diantaranya variasi larutan NaOH (0,5-2N) dan waktu proses deproteinisasi (2-5 jam) serta deasetilasi dengan NaOH (1,5-6N) dilanjutkan dengan analisis mutu hasilnya. Tahap karakterisasi meliputi penentuan sifat fisika (ukuran dan viskositas), kimia (proksimat dan derajat deasetilasi) dan mikroskopis (morfologi permukaan-poripori) dari kitosan serta uji kemampuan absorbsinya terhadap logam (Fe, Cu, Pb), pigmen ekstrak wortel, dan bakteri (E. coli). Tahap aplikasi meliputi tahap penggunaan absorben pada ekstraksi agar dan karagenan serta uji mutu hasil aplikasinya dengan viskometer (viskositas), rheoteks (gel strength), FTIR (gugus fungsi), SEM (morfologi), autosorp (distribusi pori), ONPG: Orto Nitro Phenil Glikosida (bakteri) dan HPLC (untuk uji komponen pengotor yang tersisa dan komponen utama/β-galaktosa yang sudah bersih). Hasil kitosan yang dibuat dengan kondisi deproteinisasi: NaOH 1N, waktu proses 4jam, dan deasetilasi: NaOH 6N, waktu 2jam, terpilih sebagai absorben, adalah kitosan dengan derajat deasetilasi 90%, mempunyai karakteristik fisikakimia sebagai berikut: rendemen 13,5%, tidak berwarna, lebih transparan, kadar N 4%, kadar mineral 0,2%, kadar air 10%, viskositas 247 cPs, gugus fungsi amin terdeteksi oleh FTIR pada bilangan gelombang 1639 cm-1 dan gugus fungsi hidroksi pada bilangan gelombang 3410 cm-1. Analisis SEM menunjukan morfologi kitosan yang ber pori- pori dan melalui analisis autosorp menunjukkan distribusi pori dengan variasi diameter pori antara 37,2 Å sampai 1802205 Å. Kitosan 0,1% mempunyai kemampuan mengabsobsi 1% larutan logam Fe 32%, logam Cu 26%, logam Pb 22%, ekstrak wortel sebanyak 50% (100% b/v) pewarna minuman bersoda 55% dan 2% b/v biomas E. coli 80,58%.