| dc.description.abstract | The problem regarding the processing of CPO in oil palm plantations is the
liquid waste or POME (Palm Oil Mill Effluent) produced, which has a very
dangerous impact on the environment. The management of this waste in the
production of biogas is often carried out by anaerobic treatment. However, the
inadequate utilization of a biogas sludge is commonly observed, where the high
diversity of microbial populations supports soil fertility and plant productivity. This
indicates the necessity to study the characteristics of biogas sludge towards field
applications, to assist oil palm companies in managing the remaining waste from
the anaerobic POME processing.
This dissertation contained 2 stages, starting with a pre-study to obtain several
chemical characteristics and the number of beneficial bacteria populations to be
used as an isolate source. This study was carried out by obtaining a sludge sample
from the anaerobic biogas tank of a palm oil mill in South Labuhanbatu Regency,
North Sumatra, Indonesia. Using an analytical descriptive method, this process was
subsequently accompanied by analyzing the chemical characteristics of the sludge
within January-February 2020, as well as the number of beneficial bacteria
population, including nitrogen fixing bacteria and phosphate solubilizing bacteria.
The results showed that the sludge from the anaerobic tank had a pH of 7.41 which
meets quality standards, indicating lower BOD and COD than palm oil effluent.
The population of nitrogen fixing bacteria was also more than the phosphate
solubilizing bacteria. This indicated that the bacterial population from biogas sludge
had the potential for morphological characteristics, biochemical activity, potential
testing, and identification of superior isolates.
The first research was aimed to (1) obtain the characteristics of superior
bacterial isolates from biogas sludge, with the potential to increase available P and
the N-total, as well as dissolve P, and (2) molecularly identify superior bacterial
isolates from biogas sludge. This study was conducted using a Completely
Randomized Design (CRD) with 3 replications at the Soil Biology Laboratory,
Agriculture Faculty, University of North Sumatra between March-August 2020.
The process began with the isolation, selection, potency testing, as well as the
identification of nitrogen fixing and phosphate solubilizing bacteria isolates. This
was subsequently accompanied by a synergism test, organic acid measurement, and
molecular identification. The results showed that the nitrogen fixing bacteria
isolates dominantly had flat elevation, smooth edges, milky white color, gramnegative,
round cells, as well as positive in the motility, citrate, and catalase tests,
respectively. Meanwhile, the dominant phosphate-solubilizing isolates had flat
elevation, smooth edges, milky white color, gram-negative, rod cells, and were
positive in the catalase test. The potency test showed that the nitrogen fixing
bacteria (N3) isolate had nitrogenase activity, as well as increased the N-total soil
of the highest ultisols by 2.2 nmol/h and 62.56%. The results also showed that the
phosphate solubilizing bacteria isolate (P7) was able to increase the highest
available P-content of the ultisol soil by 36.21%, and also had the highest sequential
organic compounds, namely lactic, oxalic, acetic and citric acids. The highest
phosphate solubilization index and efficiency were subsequently found in the P1
isolate (medium IPF). In addition, the P7 and P1 isolates had the highest Psolubilization
abilities from calcium triphosphate/rock phosphate (4.62 and 2.66
times) and aluminium (1.42 times) sources, compared to the control group. The
nitrogen fixing bacteria isolate (N3) and phosphate solubilizing bacteria isolate (P7)
from the biogas sludge were related to Bacillus paramycoides and Bacillus cereus,
respectively.
The second research was aimed to determine the effect of superior bacterial
isolates, biogas sludge, as well as their growth interactions and production of
upland rice on ultisol soils. This was conducted on a farmer's land at Ikahi Street,
Medan Selayang Subdistrict, Medan City, Indonesia, from October 2020 to March
2021, using a randomized block design with two factors on 3 replications. The first
factor (Factor I) indicated the use of superior bacterial isolates at a dose of 10
ml/polybag (B0 = no isolates, B1 = N3 nitrogen fixing bacteria isolates, B2 = P7
phosphate solubilizing bacteria isolates, B3 = a combination of isolates N3+P7).
However, the second factor (Factor II) was the dose of the biogas sludge (S0=
control, S1= 157.5 ml/polybag, S2= 315 ml/polybag, S3= 630 ml/polybag). These
parameters were analyzed by variance and DMRT at a 5% level. The results showed
that superior isolates (B1-B3) increased canopy dry weight, N-total and P-available
soils, N-uptake, the total phosphate-solubilizing and nitrogen-fixing bacteria
population, plant growth rate, as well as all production features of upland rice. At
a dose of 315-630 ml/polybag, the biogas sludge increased plant height and growth
rate, the number of tillers, wet and dry weights of the roots and canopy, RV (root
volume), N and P-uptake, the total nitrogen fixing bacteria population, and the
panicles on upland rice. The interaction of the nitrogen fixing isolates at a dose of
630 ml/polybag (B1S3) increased the total N-soil and N-bacteria population, as
well as the plant growth rates. Therefore, the biogas sludge contained a population
of beneficial bacteria, such as the nitrogen fixers and phosphate solubilizers, which
increased the total N and P-available acid soils (ultisol), as well as supported the
growth and production of upland rice plants. | en_US |
| dc.description.abstract | Permasalahan yang ditimbulkan saat pengolahan CPO pada perkebunan
kelapa sawit menghasilkan limbah cair atau Palm Oil Mill Effluent (POME) dan
dampaknya sangat berbahaya pada lingkungan. Pengelolaan POME dapat
dilakukan dengan pengolahan secara anaerobik dalam memproduksi biogas, namun
terdapat sludge biogas yang belum dimanfaatkan dengan baik. Tingginya
keanekaragaman populasi mikroba dari sludge biogas yang mendukung kesuburan
tanah maupun produktivitas tanaman. Oleh karena itu diperlukan beberapa
penelitian karakteristik sludge biogas sampai diaplikasikan ke lapangan untuk
membantu perusahaan kelapa sawit dalam mengelola sisa limbah dari pengolahan
POME secara anaerobik.
Penelitian disertasi ini terdiri dari 2 tahap, yang diawali dengan pra-penelitian
dengan tujuan untuk memperoleh beberapa karakteristik kimia dan jumlah populasi
bakteri yang menguntungkan dari sludge biogas limbah cair kelapa sawit yang
dapat digunakan sebagai sumber isolat. Penelitian ini dilaksanakan dengan
mengambil sampel sludge biogas dari tangki anaerob biogas pabrik kelapa sawit di
Kabupaten Labuhanbatu Selatan, Sumatera Utara kemudian dianalisis karakteristik
kimia dan jumlah populasi bakteri menguntungkan (penambat nitrogen dan pelarut
fosfat) pada Januari-Februari 2020. Penelitian ini menggunakan metode deksriptif
analitik. Hasil menunjukkan bahwa sludge biogas dari tangki anaerob biogas pabrik
kelapa sawit memiliki pH 7,41 (memenuhi standar mutu), BOD dan COD lebih
rendah dibandingkan dari limbah cair kelapa sawit. Diperoleh jumlah populasi
bakteri penambat nitrogen lebih banyak dibandingkan populasi bakteri pelarut
fosfat. Hasil ini menjadi dasar bahwa populasi bakteri dari sludge biogas berpotensi
untuk pengujian karakteristik morfologi, aktivitas biokimia dan uji potensi serta
identifikasi jenis isolat bakteri unggul.
Penelitian Tahap Pertama dengan tujuan (1) memperoleh karakteristik
isolat bakteri unggul dari sludge biogas yang potensial meningkatkan N-total,
melarutkan P dan meningkatkan P-tersedia, (2) mengidentifikasi isolat bakteri
unggul dari sludge biogas secara molekuler. Penelitian ini dilakukan di
Laboratorium Biologi Tanah, Fakultas Pertanian, Universitas Sumatera Utara
menggunakan Rancangan Acak Lengkap (RAL) dengan 3 ulangan. Penelitian ini
diawali dengan isolasi, seleksi, dan uji potensi, serta identifikasi isolat bakteri
penambat nitrogen dan pelarut fosfat, uji sinergisme, pengukuran asam organik dan
identifikasi secara molekuler. Penelitian ini dilakukan pada Maret sampai Agustus
2020. Hasil karakteristik morfologi isolat bakteri penambat nitrogen pada sludge
biogas dominan memiliki elevasi datar, tepian licin, warna putih susu, gram negatif,
sel bulat serta positif pada uji motilitas, sitrat, dan katalase, sedangkan isolat bakteri
pelarut fosfat dominan memiliki elevasi datar, tepian licin, warna putih susu, gram
negatif, sel batang serta positif pada uji katalase.
Uji potensi menunjukkan bahwa isolat bakteri penambat nitrogen (N3)
memiliki aktivitas nitrogenase dan dapat meningkatkan N-total tanah ultisol
tertinggi masing-masing sebesar 2,2 nmol/jam dan 62,56%. Isolat bakteri pelarut
fosfat (P7) dapat meningkatkan kadar P-tersedia tanah ultisol tertinggi sebesar
36,21% dibandingkan kontrol dan memiliki asam-asam organik tertinggi secara
berurutan yaitu asam laktat, asam oksalat, asam asetat, dan asam sitrat. Indeks dan
efisiensi pelarutan fosfat tertinggi terdapat pada isolat bakteri pelarut fosfat P1 (IPF
sedang). Isolat P7 memiliki kemampuan melarutkan P tertinggi dari sumber calsium
triphosphate dan batu fosfat (4,62 dan 2,66 kali), sedangkan isolat P1 memiliki
kemampuan melarutkan P tertinggi dari sumber aluminium fosfat (1,42 kali)
dibandingkan kontrol. Isolat bakteri penambat nitrogen (N3) dan bakteri pelarut
fosfat (P7) dari sludge biogas memiliki kekerabatan masing-masing dengan
Bacillus paramycoides dan Bacillus cereus.
Penelitian Tahap Kedua dengan tujuan mendapatkan pengaruh isolat
bakteri unggul, sludge biogas, dan interaksinya terhadap pertumbuhan dan produksi
padi gogo pada tanah ultisol. Penelitian ini dilakukan di lahan petani Jl. Ikahi,
Kecamatan Medan Selayang, Kota Medan, pada Oktober 2020-Maret 2021.
Penelitian ini menggunakan Rancangan Acak Kelompok dengan dua faktor pada 3
ulangan. Faktor I yaitu penggunaan jenis isolat bakteri unggul dosis 10 ml/polybag
(B0= tanpa isolat, B1= isolat bakteri penambat nitrogen N3, B2= isolat bakteri
pelarut fosfat P7, B3= kombinasi isolat N3+P7). Faktor II yaitu dosis sludge biogas
(S0= kontrol, S1= 157,5 ml/polybag, S2= 315 ml/polybag, S3= 630 ml/polybag).
Parameter penelitian ini dianalisis dengan sidik ragam dan dilanjutkan DMRT pada
taraf 5%. Hasil menunjukkan bahwa isolat bakteri unggul (B1-B3) dapat
meningkatkan bobot kering tajuk, N-total dan P-tersedia tanah, serapan N, total
populasi bakteri pelarut fosfat dan penambat nitrogen, laju pertumbuhan tanaman,
dan semua karakter produksi tanaman padi gogo. Sludge biogas dosis 315-630
ml/polybag dapat meningkatkan tinggi tanaman, jumlah anakan, bobot basah akar
dan tajuk, volume akar, bobot kering akar dan tajuk, serapan N dan P, total populasi
bakteri penambat nitrogen, laju pertumbuhan tanaman, dan jumlah malai tanaman
padi gogo. Interaksi isolat bakteri penambat nitrogen dengan sludge biogas dosis
630 ml/polybag (B1S3) dapat meningkatkan N-total tanah, total populasi bakteri
penambat nitrogen, dan laju pertumbuhan tanaman.
Berdasarkan tahapan penelitian yang telah dilakukan dapat disimpulkan
bahwa sludge biogas terdapat populasi bakteri yang menguntungkan seperti bakteri
penambat nitrogen dan pelarut fosfat yang dapat meningkatkan N-total dan Ptersedia
tanah masam (ultisol) serta mendukung pertumbuhan dan produksi
tanaman padi gogo. | en_US |
