Irawati, Maghfira Selia and Irfan Mustafa, S.Si., M.Si., Ph.D. and Farida Rahayu, S.Si., M.P., Ph.D. (2024) Bioekstraksi Lignin Dari Serasah Daun Tebu (Saccharum Officinarum L.) Menggunakan Konsorsium Bakteri Selulolitik Dan Hemiselulolitik. Magister thesis, Universitas Brawijaya.
Abstract
Tanaman tebu (Saccharum officinarum L.) merupakan tanaman yang digunakan sebagai bahan baku pada industri gula. Adanya peningkatan permintaan produk gula industri gula tentunya menghasilkan peningkatan limbah pula, salah satunya limbah pasca-panen yaitu serasah daun tebu. Limbah tersebut mengandung komponen lignoselulosa, yaitu selulosa, hemiselulosa, dan lignin. Konversi biomassa menjadi produk umumnya lebih berfokus pada pemanfaatan selulosa dan hemiselulosa saja, sedangkan komponen lignin masih belum banyak dimanfaatkan. Metode ekstraksi lignin (pre-treatment) umumnya dilakukan secara kimia. Namun, metode ini bersifat kurang ramah terhadap lingkungan dan struktur lignin yang diperoleh juga berubah. Proses pre-treatment dapat dilakukan secara biologi atau bioekstraksi dengan menggunakan bakteri. Bakteri selulolitik dan hemiselulolitik diharapkan dapat memecah serta mendegradasi struktur ikatan kimia pada selulosa dan hemiselulosa, sehingga didapatkan lignin dengan kemurnian yang tinggi. Tujuan penelitian ini adalah untuk menganalisis karakteristik bakteri selulolitik dan hemiselulolitik yang memiliki potensi terbaik dari tanah di Tempat Pembuangan Akhir (TPA) Supit Urang Kota Malang, menganalisis konsentrasi optimal inokulum konsorsium bakteri selulolitik dan hemiselulolitik pada proses bioekstraksi lignin dari serasah daun tebu (Saccharum officinarum L.) serta mengevaluasi kualitas lignin yang dihasilkan dari hasil bioekstraksi lignin dari perlakuan terbaik berdasarkan warna lignin, serta analisis FTIR (Fourier Transform Infra Red). Bakteri selulolitik dan hemiselulolitik diisolasi dari TPA Supit Urang Kota Malang menggunakan media selektif berbeda yaitu CMC dan xylan. Bakteri dikarakterisasi berdasarkan morfologi koloni kemudian dilakukan pengamatan zona bening dan dihitung nilai indeks aktivitas enzimnya. Selanjutnya dilakukan uji aktivitas enzim untuk mengetahui tingkat produksi enzim selulase dan enzim hemiselulase yang dihasilkan oleh bakteri. Bakteri yang memiliki aktivitas enzim tertinggi dikarakterisasi non ligninolitik. Kemudian dilakukan uji asosiasi pada isolat bakteri terpilih. Bakteri yang bersifat non-antagonis akan digunakan dalam penelitian. Tahap selanjutnya adalah pembuatan kurva pertumbuhan bakteri. Bakteri dengan potensi terbaik diidentifikasi berdasarkan sekuens 16S rDNA. Bioekstraksi lignin pada serasah daun tebu dilakukan dengan variasi konsentrasi inokulum konsorsium bakteri yaitu 0%, 5%, 10%, dan 15% selama 15 hari. Parameter yang diuji yaitu TPC; aktivitas enzim; pH; presentase penurunan berat kering serasah daun tebu; berat lignin; serta kadar selulosa, hemiselulosa, lignin. Berat lignin tertinggi dibandingkan dengan lignin komersial dan dikarakterisasi berdasarkan warna lignin serta FTIR. Selanjutnya, data yang diperoleh dianalisis menggunakan Analisis Varian Dua Arah (TwoWay Anova) dan dilanjutkan dengan uji BNJ.ii Hasil isolasi didapatkan 20 isolat bakteri selulolitik dan 14 bakteri hemiselulolitik. Berdasarkan hasil screening, bakteri selulolitik SL2 memiliki aktivitas selulase tertinggi yaitu 0,071 U/mL yang teridentifikasi sebagai Bacillus amyloliquefaciens F98 dengan similaritas 99,02%. Karakteristik morfologi koloni bakteri SL2 yaitu bentuk koloni tidak teratur, elevasi datar, tekstur berkontur, konsistensi lekit, ciri optik opalesens, pigmentasi putih, pinggiran beralun, bentuk sel batang (basil) dan merupakan bakteri gram positif. Bakteri hemiselulolitik HL2 memiliki aktivitas hemiselulase tertinggi yaitu 0,653 U/mL yang teridentifikasi sebagai Glutamicibacter soli NHSS28 dengan similaritas 82,46%. Karakteristik morfologi koloni bakteri HL2 yaitu bentuk tidak teratur, elevasi datar, tekstur berkontur, konsistensi tipis, ciri optik opalesens, pigmentasi putih, pinggiran menyeluruh, bentuk sel bulat (kokus) dan merupakan bakteri gram positif. Hasil karakteristik nonligniniolitik menunjukkan bahwa kedua isolat bakteri tersebut tidak bersifat ligninolitik. Berdasarkan hasil uji antagonis, kedua isolat bakteri tersebut bersifat non-antagonis karena tidak terbentuk zona bening pada daerah pertemuan antar isolat. Konsentrasi optimal inokulum konsorsium bakteri selulolitik dan hemiselulolitik pada proses bioekstraksi lignin dari serasah daun tebu (Saccharum officinarum L.) yaitu 15% (perlakuan P15) dengan persentase berat lignin yang dihasilkan yaitu 5,55% atau 1,387 g. Lignin P15 memiliki warna coklat tua. Hasil analisis FTIR (Fourier Transform Infra Red) menunjukkan pola grafik yang mirip dengan lignin komersial namun terdapat 2 puncak yang diduga merupakan kontaminan.
English Abstract
Sugarcane (Saccharum officinarum L.) is a plant that is used as raw material in the sugar industry. The increase in demand for sugar products from the sugar industry certainly results in an increase in post-harvest waste, namely sugar cane leaf. The waste is contains lignocellulose components, there are cellulose, hemicellulose, and lignin. Biomass conversion into products is generally only focused on the use of cellulose and hemicellulose, while the lignin component is still not widely used. The lignin extraction method (pretreatment) is generally done chemically (chemical method). However, this method is less friendly to the environment and the structure of lignin obtained also changes. The pretreatment process can also be done biologically, it called bioextraction. Bioextraction process can use bacteria as the agent. Cellulolytic and hemicellulolytic bacteria are expected to break down and degrade the structure of chemical bonds in cellulose and hemicellulose, so that lignin can be obtained. This bacteria can be used for lignin extraction of sugarcane biomass. The aimed of this research are to analyze the characteristics of cellulolytic and hemicellulolytic bacteria that have the highest potential from the soil at the Supit Urang Municipal Landfill, Malang City; to analyze the optimal concentration of cellulolytic and hemicellulolytic bacterial consortium inoculum in the lignin bioextraction process from sugarcane leaf (Saccharum officinarum L.) as well as evaluating the quality of lignin produced from lignin bioextraction from the best treatment based on lignin color and texture, as well as FTIR (Fourer Transform Infra Red) analysis. Cellulolytic and hemicellulolytic bacteria were isolated from the Supit Urang landfill, Malang City using different selective media, namely CMC and xylan. Bacteria were characterized based on colony morphology, then the clear zone was observed and the enzyme activity index value was calculated. Next, an enzyme activity test was carried out to determine the production level of the cellulase enzyme and hemicellulase enzyme produced by the bacteria. Bacteria that have the highest enzyme activity are characterized as nonligninolytic. Then an association test was carried out on selected bacterial isolates. Bacteria that are non-antagonistic will be used in the research. The next stage is to create a bacterial growth curve for cellulolytic and hemicellulolytic bacteria. The bacteria with the highest potential were identified based on the 16S rDNA sequence. Bioextraction of lignin from sugarcane leaf was carried out by varying the concentration of the bacterial consortium inoculum, 0%, 5%, 10% and 15%. The parameters tested are TPC; enzyme activity; pH; percentage reduction in dry weight of sugarcane leaf; lignin weight; content of cellulose, hemicellulose, lignin. The highest lignin weight was compared with commercial lignin and characterized based on color, texture and FTIR. Theiv data was analyzed using Two-Way Analysis of Variance (Two-Way Anova) and continued with the Tukey test. The isolation results showed that there were 20 isolates of cellulolytic bacteria and 14 hemicellulolytic bacteria. Based on the screening results, cellulolytic bacteria SL2 had the highest cellulase activity at 0.071 U/mL, which was identified as Bacillus amyloliquefaciens F98 with characteristics of irregular colony shape, flat elevation, contoured texture, sticky consistency, opalescent optical characteristics, white pigmentation, fluted edges, bacil cell shape and are gram-positive bacteria. The hemocellulolytic bacterium HL2 has the highest hemicellulase activity at 0.653 U/mL, which was identified as Glutamicibacter soli strain NHSS28 with characteristics of irregular shape, flat elevation, contoured texture, thin consistency, opalescent optical characteristics, white pigmentation, overall edges, round cell shape (cocci) and is a gram positive bacteria. The results of non-ligninolytic characteristics and antagonist tests showed that the two bacterial isolates were not ligninolytic and were non-antagonistic because they did not form clear zones. The optimal concentration of cellulolytic and hemicellulolytic bacterial consortium inoculum in the lignin bioextraction process from sugarcane leaf is 15% (P15) with the weight percentage of the lignin produced 5,549% or 1,387 g. Lignin P15 has a dark brown color and a rough, crystal-like texture. The results of FTIR (Fourer Transform Infra Red) analysis show a graphic pattern that is similar to commercial lignin but there are 2 peaks which are suspected to be contaminants.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | 0424090039 |
| Divisions: | S2/S3 > Magister Biologi, Fakultas MIPA |
| Depositing User: | Unnamed user with username nova |
| Date Deposited: | 06 Sep 2024 07:14 |
| Last Modified: | 06 Sep 2024 07:14 |
| URI: | http://repository.ub.ac.id/id/eprint/229108 |
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