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Bioactivation of phosphate rocks by indigenous phosphate-solubilizing fungi Bioaktivasi fosfat alam oleh fungi pelarut fosfat setempat H WIDIASTUTI; Didiek H GOENADI; . TRI-PANJI; L P SANTI; P FATURACHIM; N MARDIANA; I HARIANTO; . ISROI
E-Journal Menara Perkebunan Vol 68, No 1: Juni 2000
Publisher : INDONESIAN RESEARCH INSTITUTE FOR BIOTECHNOLOGY AND BIOINDUSTRY

Ringkasan Efektivitas fungi pelarut fosfat (FPF) dalam meningkatkan kelarutan fosfor (P) fosfat alam (FA) sangat dipengaruhi oleh kesesuaian isolat fungi dengan mineralogi batuan fosfat. Satu seri percobaan laboratorium telah dilakukan untuk menetapkan potensi supernatan kultur cair (SKC) dari FPF asal tanah dan batuan tambang FA eksCileungsi dan Madura untuk meningkatkan kelarutan FA eks-Cileungsi (FAQ dan eksMadura (FAM) dalam pembuatan superfosfat yang diaktivasi secara biologi (SPab). Kegiatan penelitian meliputi: (1) seleksi pelarutan P-FPF dalam medium Pikovskaya, (2) pengujian kemampuan pelarutan P-FAC, P-FAM, P-Ca3 (PO4)z, dan P AIP04 isolat-isolat terseleksi, dan (3) optimasi pembuatan SPab dengan isolat terpilih. Rancangan percobaan yang digunakan adalah rancangan acak lengkap dengan dua ulangan. Dari hasil isolasi diperoleh 50 isolat FPF, 17 isolat di antaranya berpotensi dalam melarutkan fosfat yang ditandai pembentukan zona bening yang intensif di sekitar koloni. Dari ketujuh belas isolat tersebut sepuluh isolat berasal dari Lulut (Cileungsi), dan tujuh isolat lainnya berasal dari Madura (masing-masing dua isolat dari Socah dan Aengnyior serta tiga isolat dari Korbe). Berdasarkan kemampuan melarutkan P dari FAC, FAM, Ca3(PO4)2, dan AIP04 diperoleh masing-masing tiga isolat dari Cileungsi dan Madura. Dari keenam isolat tersebut empat isolat di antaranya tergolong Penicillium sp. dan dua isolat lainnya termasuk Aspergillus sp. Di antara keenam isolat tersebut isolat Korbe 0909 memiliki kemampuan iertinggi dalam melarutkan P dari semua sumber P. Kandungan P-FAC lebih tinggi daripada FAM dan mendekati FA eks Maroko. SKC dapat menggantikan fungsi H2SO4 (98%) dalam melarutkan P-FA. SPab Cileungsi mengandung P nyata lebih tinggi daripada FAC yang diaktivasi secara konvensional, namun pada SPab Madura kandungan P larut air nyata lebih rendah, sedangkan P larut asam sitrat 2% dan perklorat sebanding dengan FAM yang diaktivasi secara konvensional. Aktivasi FA oleh SKC dapat menurunkan konsentrasi asam fosfat (H3PO4) dari 52% menjadi 42%. Kelarutah P (asam sitrat 2% dan air) dan kandungan sulfur-SPab Cileungsi dan Madura nyata lebih rendah dibandingkan dengan SP36.Summary The effectiveness of phosphate-solubilizing fungi (PSF) in enhancing phosphorus (P) solubility of phosphate rocks (PR) is assumed to be dependent on the suitability of the fungal isolate to the mineralogycal composition of the rocks. A laboratory study was conducted to determine the phosphate solubilizing ability of liquid culture supernatants (LCS) of PSF isolated from various PR deposits and adjacent soils, i.e. at Cileungsi in West Java and the island of Madura in East Java to enhance the reactivity of PR from deposits at Cileungsi (CPR) and Madura (MPR) and their potential use as agents in the production of biologically-activated superphosphate (SPab). Three series of laboratory experiments were conducted: (1) screening isolate on the solubilization of P in Pikovskaya medium; (2) assaying the ability of selected isolates on solubilization of P-CPR, PMPR, P-Ca3(P04)2 and P-AIPO4, and (3) optimizing superphosphate fertilizer formulation. Completely random design was used as the experimental design with two replicates. Seventeen out of 50 PSF isolates were characterized to be highly potential as phosphate solubilizers, as indicated by clear zone formation. Ten isolates were from Lulut (Cileungsi) and seven from Madura island, two from Socah and Aengnyior respectively, and remaining three from Korbe. Regarding the ability of P solubilization of four P sources, six isolates were selected, three each from Cileungsi and Madura. Of these six isolates, four are Penicillium sp., and four belong to Aspergillus sp. The Aspergillus sp. isolate Korbe 0909 was found to be the highest in P-solubilization of various sources of P. Based on the P dissolving ability of P-CPR and their effectiveness in substituting for sulphuric acid (98%) usually used in conventional production of superphosphate, the LCS of Korbe 0909 improved significantly the P-PRs dissolution. MPR activated by the LCS yielded a comparable values of 2% citric acid-soluble P content and significantly lower water-soluble P compared with conventional method: Reduction of phosphoric acid (H3PO4) concentration from 52% to 42%, in combination with LCS treatment, produced P dissolution comparable to the conventional method. Although the P solubilization of CSPab and MsPab in both 2% citric acid and water as well as thus content were significantly lower compared with SP36.

Solubilization of insoluble phosphates by Aspergillus niger Pelarutan fosfat sukar larut oleh Aspergillus niger LAKSMITA P SANTI; D H GOENADI; . SISWANTO; I SAILAH; . ISROI
E-Journal Menara Perkebunan Vol 68, No 2: Desember 2000
Publisher : INDONESIAN RESEARCH INSTITUTE FOR BIOTECHNOLOGY AND BIOINDUSTRY

RingkasanPenggunaan langsung fosfat alam (FA) ke dalam tanah sebagai sumber pupuk P telah dilakukan selama bertahun-tahun melalui beberapa macam cara penggunaan. Kualitas FA di Indonesia umumnya rendah dan ketersediaan bahan baku yang berkualitas untuk produksi pupuk fosfat terlarut relatif terbatas. Beberapa mikroba asal tanah yang dapat melarutkan fosfat anorganik telah banyak dilaporkan. Namun, informasi yang tersedia tentang mekanisme pelarutan P dari FA lokal asal Indonesia dan P anorganik oleh Aspergillus niger BCC F194 belum banyak diteliti. Satu seri penelitian laboratorium telah dilaksanakan untuk mengetahui kemampuan A. niger BCC F194 melarutkan P. Evaluasi agronomi FA lokal (FA Cileungsi dan Madura) di rumah kaca juga telah dilakukan. A. niger BCC F194 dapat melarutkan sumber P sukar larut, yaitu FA Cileungsi dan Madura, serta senyawa Ca3(PO4)2 dan AlPO4. Kelarutan P anorganik tersebut berhubungan dengan peningkatan aktivitas proton (H*) yang menyebabkan penurunan pH medium dan produksi asam organik. Asam organik utama yang dihasilkan oleh A. niger BCC F194 dalam medium cair Pikovskaya yang dimodifikasi adalah asam oksalat (3.75 mM), asam sitrat (2.0 mM), dan asam glukonat (0.9 mM). Kelarutan FA Cileungsi lebih besar dibandingkan dengan FA Madura, dan kelarutan Ca3(PO4)2 lebih besar dibandingkan kelarutan AlPO4. Tidak ada korelasi antara kelarutan P anorganik dengan aktivitas enzim fosfatase, walaupun aktivitas enzim fosfatase cukup tinggi terdeteksi dalam medium. Satu formula biosuperfosfat telah berhasil dirakit dengan mereaksikan FA lokal dengan supernatan kultur cair (SKC) pengganti asam sulfat. Hasil percobaan padabibit kakao, karet dan kelapa sawit di rumah kaca menunjukkan bahwa prototipe pupuk biosuperfosfat dengan bahanbaku FA Cileungsi dan Madura bentuk granul maupun serbuk, memiliki nilai efektivitas agronomi yang relatif menyamai SP-konvensional. SummaryThe direct application of rock phosphate (RP) to soils as a source of phosphorus (P) fertilizer has been employed with varying popular methods over the years. The RP in Indonesia has low quality for plant fertilization and the availability of the raw material with good quality for production of soluble phosphate fertilizers is limited. Many common soil microbes that can dissolve insoluble inorganic phosphate have been extensively studied. However, there is little information on mechanism of P-solubilization from local RP of Indonesia and inorganic P by Aspergillus niger BCC F194 isolated from tropical acid soils. A laboratory study was conducted to determine the ability of phosphate solubilization A. niger BCC F194. Agronomic evaluation of bioactivated local RP, i.e. Cileungsi and Madura phosphate rocks (CRP and MRP) for direct application in greenhouse experiment was also conducted. A. niger BCC F194 was able in solubilizing different types of hardly-soluble phosphates, i.e. CRP and MRP, Ca3(PO4)2, and AlPO4 compounds. Inorganic P solubilization was directly correlated to the organic acid production and increasing proton (H+) activities causing pH to decrease and production of organic acid. The major acidic metabolites produced by A. niger BCC F 194 in modified liquid culture Pikovskaya medium were oxalic acid (3.75 mM), citric acid (2.0 mM), and gluconic acid (0.9 mM). The solubilization of Cileungsi RP was higher than that of Madura RP, and the solubilization of Ca3(PO4)2 was better than that of AlPO4. No correlation between solubilization of inorganic P and enzyme activities, although high activities of phosphatase enzyme were detectable in the medium. A biosuperphosphate formula had been constructed by reacting local RP with liquid culture supernatant (LCS) replacing sulfuric acid. Results of cocoa, rubber, and oil palm seedlings experiments in greenhouse indicate that both granular and powder biosuperphosphate prototypes commonly had a comparable relative agronomic effectiveness value to that of the conventional SP.

Extraction and characterization of humic acid from plantation’s solid organic waste composts Ekstraksi dan karakterisasi asam humat dari kompos limbah padat organik perkebunan LAKSMITA P.SANTI P SANTI; D H GOENADI; H WIDIASTUTI; N MARDIANA; . ISROI
E-Journal Menara Perkebunan Vol 68, No 2: Desember 2000
Publisher : INDONESIAN RESEARCH INSTITUTE FOR BIOTECHNOLOGY AND BIOINDUSTRY

Ringkasan Kompos dari limbah padat organik (LPO) perkebunan memiliki kandungan asam humat yang relatif tinggi. Namun, metode ekstraksi dan karakteristik asam humat asal kompos tersebut belum banyak diteliti. Oleh karena itu suatu rangkaian penelitian dilakukan dengan tujuan memperoleh paket teknologi ekstraksi dan menetapkan karakteristik asam humat asal kompos tandan kosong kelapa sawit (TKKS), kulit buah kakao (KBK), dan sisa pangkasan teh (SPT). Pengomposan dilakukan melalui tahapan pengumpulan limbah organik padat perkebunan, pencacahan, pencampuran dengan bioaktivator, inkubasi dan pemanenan. Hasil penelitian menunjukkan bahwa metode ekstraksi konvensional dengan larutan NaOH dalam atmosfer udara dapat digunakan untuk ekstraksi skala semi pilot. Jumlah asam humat yang dihasilkan dari kompos asal TKKS dan SPT lebih banyak apabila dibandingkan dengan asam humat asal kompos KBK. Waktu inkubasi pengomposan dan metode ekstraksi dengan gas N2 atau udara yang digunakan tidak berpengaruh nyata terhadap perolehan asam humat. Pemurnian asam humat asal ketiga jenis LPO perkebunan dengan menggunakan kolom Sephadex G-50 mengindikasikan bahwa asam humat asal kompos TKKS, KBK, dan SPT tersebut memiliki fraksi bobot molekul rendah serta didominasi oleh asam amino aspartat dan glutamat. Konsentrasi asam amino dan senyawa karboksilat tertinggi terdeteksi pada asam humat asal kompos SPT. Summary The plantation’s solid organic waste (SOW) composts contain relatively high humic acid (HA) substances. However, there is little information on extraction and characteristics of HA from the SOW-originated composts. An investigation has been conducted to determine extraction and characterisation of HA from empty fruit bunches of oil palm (EFBOP), cocoa pod husks (CPH), and tea cutting residues (TCR). Composting was conducted using the method that involved SOW collection, shredding, mixing with bioactivator, incubation, and harvesting. The results showed that conventional extraction method using NaOH solution under air atmosphere could be used for pilot scale extraction of humic acids (Has). Amount of humic acid from EFBOP and TCR were higher than that of CPH. The composting period and the extraction method under air or N2 gas were not significantly affected the amount of the humid acid obtained. Purification of HA extracted from EFBOP, TCR, and CPH composts by using Sephadex G-50 column indicated that EFBOP, TCR, and CPH contained HAs with lower molecular weight fractions and predominated by aspartic and glutamic acids. The highest concentration of amino acids and carboxyl compounds were detected in the TCR-originated compost

Bioactivation of phosphate rocks by indigenous phosphate-solubilizing fungi Bioaktivasi fosfat alam oleh fungi pelarut fosfat setempat H WIDIASTUTI; Didiek H GOENADI; . TRI-PANJI; L P SANTI; P FATURACHIM; N MARDIANA; I HARIANTO; . ISROI
Menara Perkebunan Vol. 68 No. 1: 68(1), 2000
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v68i1.137

Ringkasan Efektivitas fungi pelarut fosfat (FPF) dalam meningkatkan kelarutan fosfor (P) fosfat alam (FA) sangat dipengaruhi oleh kesesuaian isolat fungi dengan mineralogi batuan fosfat. Satu seri percobaan laboratorium telah dilakukan untuk menetapkan potensi supernatan kultur cair (SKC) dari FPF asal tanah dan batuan tambang FA eksCileungsi dan Madura untuk meningkatkan kelarutan FA eks-Cileungsi (FAQ dan eksMadura (FAM) dalam pembuatan superfosfat yang diaktivasi secara biologi (SPab). Kegiatan penelitian meliputi: (1) seleksi pelarutan P-FPF dalam medium Pikovskaya, (2) pengujian kemampuan pelarutan P-FAC, P-FAM, P-Ca3 (PO4)z, dan P AIP04 isolat-isolat terseleksi, dan (3) optimasi pembuatan SPab dengan isolat terpilih. Rancangan percobaan yang digunakan adalah rancangan acak lengkap dengan dua ulangan. Dari hasil isolasi diperoleh 50 isolat FPF, 17 isolat di antaranya berpotensi dalam melarutkan fosfat yang ditandai pembentukan zona bening yang intensif di sekitar koloni. Dari ketujuh belas isolat tersebut sepuluh isolat berasal dari Lulut (Cileungsi), dan tujuh isolat lainnya berasal dari Madura (masing-masing dua isolat dari Socah dan Aengnyior serta tiga isolat dari Korbe). Berdasarkan kemampuan melarutkan P dari FAC, FAM, Ca3(PO4)2, dan AIP04 diperoleh masing-masing tiga isolat dari Cileungsi dan Madura. Dari keenam isolat tersebut empat isolat di antaranya tergolong Penicillium sp. dan dua isolat lainnya termasuk Aspergillus sp. Di antara keenam isolat tersebut isolat Korbe 0909 memiliki kemampuan iertinggi dalam melarutkan P dari semua sumber P. Kandungan P-FAC lebih tinggi daripada FAM dan mendekati FA eks Maroko. SKC dapat menggantikan fungsi H2SO4 (98%) dalam melarutkan P-FA. SPab Cileungsi mengandung P nyata lebih tinggi daripada FAC yang diaktivasi secara konvensional, namun pada SPab Madura kandungan P larut air nyata lebih rendah, sedangkan P larut asam sitrat 2% dan perklorat sebanding dengan FAM yang diaktivasi secara konvensional. Aktivasi FA oleh SKC dapat menurunkan konsentrasi asam fosfat (H3PO4) dari 52% menjadi 42%. Kelarutah P (asam sitrat 2% dan air) dan kandungan sulfur-SPab Cileungsi dan Madura nyata lebih rendah dibandingkan dengan SP36.Summary The effectiveness of phosphate-solubilizing fungi (PSF) in enhancing phosphorus (P) solubility of phosphate rocks (PR) is assumed to be dependent on the suitability of the fungal isolate to the mineralogycal composition of the rocks. A laboratory study was conducted to determine the phosphate solubilizing ability of liquid culture supernatants (LCS) of PSF isolated from various PR deposits and adjacent soils, i.e. at Cileungsi in West Java and the island of Madura in East Java to enhance the reactivity of PR from deposits at Cileungsi (CPR) and Madura (MPR) and their potential use as agents in the production of biologically-activated superphosphate (SPab). Three series of laboratory experiments were conducted: (1) screening isolate on the solubilization of P in Pikovskaya medium; (2) assaying the ability of selected isolates on solubilization of P-CPR, PMPR, P-Ca3(P04)2 and P-AIPO4, and (3) optimizing superphosphate fertilizer formulation. Completely random design was used as the experimental design with two replicates. Seventeen out of 50 PSF isolates were characterized to be highly potential as phosphate solubilizers, as indicated by clear zone formation. Ten isolates were from Lulut (Cileungsi) and seven from Madura island, two from Socah and Aengnyior respectively, and remaining three from Korbe. Regarding the ability of P solubilization of four P sources, six isolates were selected, three each from Cileungsi and Madura. Of these six isolates, four are Penicillium sp., and four belong to Aspergillus sp. The Aspergillus sp. isolate Korbe 0909 was found to be the highest in P-solubilization of various sources of P. Based on the P dissolving ability of P-CPR and their effectiveness in substituting for sulphuric acid (98%) usually used in conventional production of superphosphate, the LCS of Korbe 0909 improved significantly the P-PRs dissolution. MPR activated by the LCS yielded a comparable values of 2% citric acid-soluble P content and significantly lower water-soluble P compared with conventional method: Reduction of phosphoric acid (H3PO4) concentration from 52% to 42%, in combination with LCS treatment, produced P dissolution comparable to the conventional method. Although the P solubilization of CSPab and MsPab in both 2% citric acid and water as well as thus content were significantly lower compared with SP36.

Extraction and characterization of humic acid from plantation’s solid organic waste composts Ekstraksi dan karakterisasi asam humat dari kompos limbah padat organik perkebunan LAKSMITA P.SANTI P SANTI; D H GOENADI; H WIDIASTUTI; N MARDIANA; . ISROI
Menara Perkebunan Vol. 68 No. 2: 68 (2), 2000
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v68i2.141

Ringkasan Kompos dari limbah padat organik (LPO) perkebunan memiliki kandungan asam humat yang relatif tinggi. Namun, metode ekstraksi dan karakteristik asam humat asal kompos tersebut belum banyak diteliti. Oleh karena itu suatu rangkaian penelitian dilakukan dengan tujuan memperoleh paket teknologi ekstraksi dan menetapkan karakteristik asam humat asal kompos tandan kosong kelapa sawit (TKKS), kulit buah kakao (KBK), dan sisa pangkasan teh (SPT). Pengomposan dilakukan melalui tahapan pengumpulan limbah organik padat perkebunan, pencacahan, pencampuran dengan bioaktivator, inkubasi dan pemanenan. Hasil penelitian menunjukkan bahwa metode ekstraksi konvensional dengan larutan NaOH dalam atmosfer udara dapat digunakan untuk ekstraksi skala semi pilot. Jumlah asam humat yang dihasilkan dari kompos asal TKKS dan SPT lebih banyak apabila dibandingkan dengan asam humat asal kompos KBK. Waktu inkubasi pengomposan dan metode ekstraksi dengan gas N2 atau udara yang digunakan tidak berpengaruh nyata terhadap perolehan asam humat. Pemurnian asam humat asal ketiga jenis LPO perkebunan dengan menggunakan kolom Sephadex G-50 mengindikasikan bahwa asam humat asal kompos TKKS, KBK, dan SPT tersebut memiliki fraksi bobot molekul rendah serta didominasi oleh asam amino aspartat dan glutamat. Konsentrasi asam amino dan senyawa karboksilat tertinggi terdeteksi pada asam humat asal kompos SPT. Summary The plantation’s solid organic waste (SOW) composts contain relatively high humic acid (HA) substances. However, there is little information on extraction and characteristics of HA from the SOW-originated composts. An investigation has been conducted to determine extraction and characterisation of HA from empty fruit bunches of oil palm (EFBOP), cocoa pod husks (CPH), and tea cutting residues (TCR). Composting was conducted using the method that involved SOW collection, shredding, mixing with bioactivator, incubation, and harvesting. The results showed that conventional extraction method using NaOH solution under air atmosphere could be used for pilot scale extraction of humic acids (Has). Amount of humic acid from EFBOP and TCR were higher than that of CPH. The composting period and the extraction method under air or N2 gas were not significantly affected the amount of the humid acid obtained. Purification of HA extracted from EFBOP, TCR, and CPH composts by using Sephadex G-50 column indicated that EFBOP, TCR, and CPH contained HAs with lower molecular weight fractions and predominated by aspartic and glutamic acids. The highest concentration of amino acids and carboxyl compounds were detected in the TCR-originated compost

Solubilization of insoluble phosphates by Aspergillus niger Pelarutan fosfat sukar larut oleh Aspergillus niger LAKSMITA P SANTI; D H GOENADI; . SISWANTO; I SAILAH; . ISROI
Menara Perkebunan Vol. 68 No. 2: 68 (2), 2000
Publisher : INDONESIAN OIL PALM RESEARCH INSTITUTE

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22302/iribb.jur.mp.v68i2.142

RingkasanPenggunaan langsung fosfat alam (FA) ke dalam tanah sebagai sumber pupuk P telah dilakukan selama bertahun-tahun melalui beberapa macam cara penggunaan. Kualitas FA di Indonesia umumnya rendah dan ketersediaan bahan baku yang berkualitas untuk produksi pupuk fosfat terlarut relatif terbatas. Beberapa mikroba asal tanah yang dapat melarutkan fosfat anorganik telah banyak dilaporkan. Namun, informasi yang tersedia tentang mekanisme pelarutan P dari FA lokal asal Indonesia dan P anorganik oleh Aspergillus niger BCC F194 belum banyak diteliti. Satu seri penelitian laboratorium telah dilaksanakan untuk mengetahui kemampuan A. niger BCC F194 melarutkan P. Evaluasi agronomi FA lokal (FA Cileungsi dan Madura) di rumah kaca juga telah dilakukan. A. niger BCC F194 dapat melarutkan sumber P sukar larut, yaitu FA Cileungsi dan Madura, serta senyawa Ca3(PO4)2 dan AlPO4. Kelarutan P anorganik tersebut berhubungan dengan peningkatan aktivitas proton (H*) yang menyebabkan penurunan pH medium dan produksi asam organik. Asam organik utama yang dihasilkan oleh A. niger BCC F194 dalam medium cair Pikovskaya yang dimodifikasi adalah asam oksalat (3.75 mM), asam sitrat (2.0 mM), dan asam glukonat (0.9 mM). Kelarutan FA Cileungsi lebih besar dibandingkan dengan FA Madura, dan kelarutan Ca3(PO4)2 lebih besar dibandingkan kelarutan AlPO4. Tidak ada korelasi antara kelarutan P anorganik dengan aktivitas enzim fosfatase, walaupun aktivitas enzim fosfatase cukup tinggi terdeteksi dalam medium. Satu formula biosuperfosfat telah berhasil dirakit dengan mereaksikan FA lokal dengan supernatan kultur cair (SKC) pengganti asam sulfat. Hasil percobaan padabibit kakao, karet dan kelapa sawit di rumah kaca menunjukkan bahwa prototipe pupuk biosuperfosfat dengan bahanbaku FA Cileungsi dan Madura bentuk granul maupun serbuk, memiliki nilai efektivitas agronomi yang relatif menyamai SP-konvensional. SummaryThe direct application of rock phosphate (RP) to soils as a source of phosphorus (P) fertilizer has been employed with varying popular methods over the years. The RP in Indonesia has low quality for plant fertilization and the availability of the raw material with good quality for production of soluble phosphate fertilizers is limited. Many common soil microbes that can dissolve insoluble inorganic phosphate have been extensively studied. However, there is little information on mechanism of P-solubilization from local RP of Indonesia and inorganic P by Aspergillus niger BCC F194 isolated from tropical acid soils. A laboratory study was conducted to determine the ability of phosphate solubilization A. niger BCC F194. Agronomic evaluation of bioactivated local RP, i.e. Cileungsi and Madura phosphate rocks (CRP and MRP) for direct application in greenhouse experiment was also conducted. A. niger BCC F194 was able in solubilizing different types of hardly-soluble phosphates, i.e. CRP and MRP, Ca3(PO4)2, and AlPO4 compounds. Inorganic P solubilization was directly correlated to the organic acid production and increasing proton (H+) activities causing pH to decrease and production of organic acid. The major acidic metabolites produced by A. niger BCC F 194 in modified liquid culture Pikovskaya medium were oxalic acid (3.75 mM), citric acid (2.0 mM), and gluconic acid (0.9 mM). The solubilization of Cileungsi RP was higher than that of Madura RP, and the solubilization of Ca3(PO4)2 was better than that of AlPO4. No correlation between solubilization of inorganic P and enzyme activities, although high activities of phosphatase enzyme were detectable in the medium. A biosuperphosphate formula had been constructed by reacting local RP with liquid culture supernatant (LCS) replacing sulfuric acid. Results of cocoa, rubber, and oil palm seedlings experiments in greenhouse indicate that both granular and powder biosuperphosphate prototypes commonly had a comparable relative agronomic effectiveness value to that of the conventional SP.

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