Rohmah, Nita Shilfiani (2019) Uji Potensi serta Identifikasi Bakteri Rhizosfer dan Endofit Awar-Awar (Ficus Septica Burm.F) sebagai Agen Pendukung Fitoremediasi Tanah Terkontaminasi Kromium. Magister thesis, Universitas Brawijaya.
Abstract
Kromium heksavalen (Cr (VI)) dari limbah industri penyamakan kulit berpotensi sebagai pencemar lingkungan dan toksik terhadap manusia dan organisme lainnya. Lingkungan terkontaminasi Cr (VI) dapat diremediasi dengan memanfaatkan bakteri. Bakteri memiliki kemampuan akumulasi dan reduksi Cr (VI) yang toksik menjadi Cr (III) yang kurang toksik, tetapi bakteri memiliki keterbatasan dalam mengakumulasi logam berat tersebut. Aktivitas bakteri ini perlu diasosiasikan dengan tumbuhan yang berperan sebagai agen pengakumulasi logam berat. Namun, pertumbuhan tumbuhan terhambat sebagai respon terhadap konsentrasi logam berat yang tinggi. Kelompok bakteri rhizosfer dan endofit diketahui dapat menghasilkan indole acetic acid (IAA), fosfat terlarut, dan eksopolisakarida (EPS), sehingga bakteri tersebut dapat dijadikan sebagai bioinokulan untuk memperbaiki fungsi metabolik dan meningkatkan ketahanan tumbuhan terhadap toksisitas Cr (VI). Tujuan dari penelitian ini adalah untuk menganalisis toleransi bakteri rhizosfer dan endofit terhadap Cr (VI) dan kemampuan akumulasinya, serta menganalisis potensinya sebagai agen pendukung fitoremediasi Cr (VI). Bakteri rhizosfer dan endofit masing-masing diisolasi dari tanah perakaran dan bagian daun tumbuhan awar-awar (Ficus septica Burm F.) di kawasan pembuangan limbah penyamakan kulit di Kota Malang. Bakteri diskrining berdasarkan tingkat toleransinya terhadap berbagai konsentrasi Cr (VI). Isolat yang memiliki toleransi tinggi diuji potensinya dalam menghasilkan IAA, EPS, dan melarutkan fosfat serta keberadaan gen ChR yang terlibat dalam reduksi Cr (VI) menjadi Cr (III). Data dianalisis ragam (ANOVA) menggunakan program SPSS Software v.16. Bakteri rhizosfer dan endofit paling potensial diuji kemampuan akumulasi Cr (VI) dan diidentifikasi berdasarkan sekuen 16S rDNA. Sekuen-sekuan 16S rDNA dikonstruksi pohon filogeni berdasarkan algoritma Neighbor-Joining menggunakan program MEGA 7. Empat isolat bakteri rhizosfer (R7, R9, R10, dan R12) dan tiga isolat bakteri endofit (E3, E4, dan E8) yang masing-masing toleran terhadap Cr (VI) hingga konsentrasi 800 mg/L dan 900 mg/L. Ketujuh isolat tersebut mampu menghasilkan IAA, melarutkan fosfat, dan menghasilkan EPS. Kemampuan produksi IAA dan pelarutan fosfat tertinggi ditunjukkan oleh isolat R9 (25,08 μg/mL dan 150,98 μg/mL), sedangkan produksi EPS tertinggi ditemukan pada isolat R12 yaitu 20 μg/mL. Gen ChR ditemukan pada isolat R10, R12, E3, E4, dan E8. Isolat R12 dan E8 yang memiliki gen ChR juga menunjukkan tingginya produksi IAA, pelarutan fosfat dan produksi EPS. Hal ini menjadikan kedua isolat tersebut paling potensial sebagai agen pendukung fitoremediasi Cr (VI) dibandingkan dengan isolat lain. Gen ChR isolat R12 dan E8 masing-masing memiliki similaritas 100% dan 97,3% dengan chromate transport protein Bacillus subtilis OX 1423 dan chromate transporter Enterobacter cloacae OX 550. Protein transporter tersebut bertindak sebagai pompa efflux dan berperan dalam resistensi Cr (VI). Dua isolat potensial (R12 dan E8) masing-masing menunjukkan similaritas 100% dengan Bacillus subtilis NRS 744T dan Enterobacter cloacae ATCC 13047
English Abstract
Hexavalent chromium (Cr (VI)) from the tannery industrial waste has the potency to be an environmental pollutant because of its toxic effects on humans and other organisms. Cr (VI) contaminated environment can be remediated by using bacteria. Bacteria have the ability to accumulate and reduce the toxic Cr (VI) to less toxic Cr (III), but the bacteria have limitations in heavy metals accumulation. This bacterial activity needs to be associated with plants that act as heavy metal accumulating agents. However, plant growth is inhibited by high concentration of heavy metals. Rhizospheric and endophytic bacterial groups able to produce indole acetic acid (IAA), solubilize phosphate, and produce exopolysaccharides (EPS), so that these bacteria can be used as bioinoculants to improve metabolic function and enhance plant resistance to Cr (VI) toxicity. The objectives of this study were to analyze Cr (VI) tolerance, accumulation, and potency of rhizospheric and endophytic bacteria as promoting agents for phytoremediation of Cr (VI). Rhizospheric and endophytic bacteria were isolated from rhizospheric soil and leaf of Ficus septica Burm F. respectively, in the tannery waste disposal area in Malang City. Bacteria were screened based on their tolerance to various Cr (VI) concentrations. High tolerant isolates were determined for their potency to produce IAA, EPS, phosphate solubilizing and the presence of ChR genes that involved in reducing of Cr (VI) to Cr (III). Data were analyzed by analysis of variance (ANOVA) using SPSS Software v.16. The most potential rhizospheric and endophytic bacteria were determined based on the ability of Cr (VI) accumulation and identified based on 16S rDNA sequences. The phylogeny trees were constructed based on the Neighbor-Joining algorithm using the MEGA 7 program. Four isolates of rhizospheric bacteria (R7, R9, R10, and R12) and three isolates of endophytic bacteria (E3, E4, and E8) were tolerant to Cr (VI) until concentrations 800 mg/L and 900 mg/L. The seven isolates were able to produce IAA, solubilize phosphate, and produce EPS. The highest IAA production and phosphate solubility ability was shown by R9 isolate (25.08 μg/mL and 150.98 μg/mL), while R12 isolate has the highest EPS production was 20 μg/mL. The ChR gene was detected in R10, R12, E3, E4, and E8 isolates. The isolates that have the ChR gene (R12 and E8) also showed high IAA production, phosphate dissolution and EPS production. This makes the two isolates were the most potential supporting agents of phytoremediation of Cr (VI) compared to other isolates. ChR gene of R12 and E8 isolates have 100% and 97.3% similarities with chromate transport protein Bacillus subtilis OX 1423 and the chromate transporter Enterobacter cloacae OX 550, respectively. The transporter protein acts as an efflux pump and plays a role in Cr (VI) resistance. Two potential isolates (R12 and E8) showed 100% similarity with Bacillus subtilis NRS 744T and Enterobacter cloacae ATCC 13047, respectively
Other obstract
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| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | TES/577.57/ROH/u/2019/041911399 |
| Uncontrolled Keywords: | RHIZOSPHERE, BACTERIA, FICUS (PLANTS), PHYTOREMEDIATION, CHROMIUM |
| Subjects: | 500 Natural sciences and mathematics > 577 Ecology > 577.5 Ecology of miscellaneous environments > 577.57 Rhizophere |
| Divisions: | S2/S3 > Magister Biologi, Fakultas MIPA |
| Depositing User: | Budi Wahyono Wahyono |
| Date Deposited: | 08 Jan 2020 02:56 |
| Last Modified: | 25 Oct 2021 03:57 |
| URI: | http://repository.ub.ac.id/id/eprint/177629 |
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