Isolasi, Skrining Dan Identifikasi Jamur Xilanolitik Lokal Yang Berpotensi Sebagai Agensia Pemutih Pulp Yang Ramah Lingkungan (Isolation, Screening and Identification Xylanolytic Local Fungi That Potentially as Pulp Bleaching Agents)

Xilanase merupakan enzim yang berfungsi luas dalam bidang industri. Xilanase digunakan sebagai perlakuan awal proses pemutihan kertas di industri pulp dan kertas sehingga dapat mengurangi penggunaan senyawa klorin yang berbahaya bagi lingkungan. Xilanase yang cocok digunakan dalam industri pulp dan kertas seharusnya bebas dari aktivitas selulase. Jamur merupakan salah satu kelompok mikrobia yang mampu menghasilkan xilanase. Penelitian ini bertujuan untuk memperoleh isolat jamur unggul lokal penghasil xilanase dari tanah yang diasumsikan memiliki kandungan xilan tinggi. Tanah di sekitar industri pulp dan kertas; hutan akasia di Kab. Muara Enim dan Ogan Ilir, Sumatera Selatan; hutan Wanagama, Yogyakarta; penggergajian kayu di kota Palembang dan Yogyakarta serta TPA Palembang digunakan sebagai sumber isolat jamur. Berdasarkan skrining awal dalam media basal xilan agar diketahui bahwa dari 111 isolat jamur yang diperoleh, sebagian besar mempunyai potensi menghasilkan xilanase, akan tetapi hanya 12 isolat yang mempunyai kemampuan xilanolitik tinggi. Skrining selanjutnya dilakukan pada media basal xilan cair menunjukkan bahwa jamur yang diidentifikasi sebagai Chaetomium globosum, Penicillium simplicissimum, Aspergillus tamarii dan Monocillium sp. berpotensi unggul dalam menghasilkan xilanase dibandingkan isolat lainnya berdasarkan aktivitas enzim spesifiknya. Keempat jamur tersebut diketahui juga memiliki aktivitas lignolitik dan selulolitik. Oleh karena itu, xilanase yang diproduksi ke empat jamur tersebut berpotensi dikembangkan sebagai agen pemutih pulp

Isolation and Selection of Rhizobium Tolerant to Pesticides and Aluminum From Acid Soils in Indonesia

Application of Rhizobium as inoculum in acid soil requires specific characters, namely high tolerance to pesticide residues, soil acidity, and high concentration of Aluminum. This study was conducted to isolate Rhizobium having these characters. Inspite of acid soils from Kalimantan, Sumatra, Sulawesi and Java; root nodules of legumes planted in those regions were used as source of isolates. Rhizobial isolation was done using direct isolation andenrichment technique. A paper disc diffusion technique was used in selecting tolerance to pesticides. The selected isolates were examined the tolerance to pH, Al, and ability to form root nodule with soybean. From soil analysis, it could be seen the correlation between pH value and Al concentration. It means that the lower pH value the higher Al concentration. The number of Rhizobium isolates and its tolerance to paraquat was depended on soil type. From 173 strains of isolated Rhizobium, 24 strains were tolerance to pesticides and Aluminum. They were able to grow in wide range of pH, namely 3 – 8, or some of them in 5 - 8. Around 92% of the selected bacteria could form root nodules with soybean plant in different number and size. Hopefully, these isolates can be applied in the pesticide polluted agricultural lands, especially in acid soils with high concentration of Al, and it can also increase soybean production

Karakterisasi Bakteri Pendegradasi Fenol Dan Pembentuk Biofilm Dari Sumber Alami Dan Artifisial

Fenol merupakan salah satu polutan air tanah yang memiliki sifat toksik bagi manusia maupun lingkungan. Salah satu teknologi yang dapat diaplikasikan untuk pengolahan limbah fenol adalah melalui bioremediasi dengan memanfaatkan aktivitas bakteri. Secara umum, bakteri di alam akan tumbuh dan membentuk biofilm. Bakteri pembentuk biofilm memiliki beberapa kelebihan, diantaranya mampu bertahan hidup dalam lingkungan yang kurang menguntungkan serta meningkatkan degradasi senyawa rekalsitran, karena bakteri akan saling berinteraksi dan saling melengkapi proses metabolik yang ada. Penelitian ini ditujukan untuk karakterisasi dan identifikasi isolat bakteri pendegradasi fenol dan pembentuk biofilm yang diperoleh dari limbah cair rumah sakit dan industri tekstil serta dari tanah gambut. Karakter yang diamati meliputi karakter morfologi koloni dan sel, serta karakter biokimiawi. Hasil karakterisasi selanjutnya digunakan untuk identifikasi menggunakan analisis profile matching isolat terpilih berdasarkan Bergey's Manual of Determinative Bacteriology. Hasil menunjukkan bahwa bakteri yang diperoleh dari limbah cair rumah sakit memiliki karakter yang mirip dengan Genus Micrococcus (isolat DL120), Genus Enterobacter (DOK135), dan Genus Bacillus (ATA6). Isolat TU3 dari limbah cair industri tekstil mirip dengan Genus Flavobacterium. Isolat HG1, SG3, dan HP3 yang diperoleh dari tanah gambut berturut-turut menunjukkan karakter yang mirip dengan Genus Alcaligenes, Arthrobacter, dan Rhodococcus

Paraquat Toxicity on the Growth of Rhizobium SP. in a Synthetic Medium

Toxicity of paraquat on the growth of several strains of Rhizobium sp. in Yeast Extract Mannitol medium was studied. Various concentrations of paraquat 100, ranged from O (control) to 100 ppm were applied. Qualitative examination was done using paper disc diffusion technique, and the quantitative examination was conducted based on the change in cell density in medium measured by plate count method.Qualitative data showed that effect or paraquat was species specific. Some strains of Rhizobium sp., namely Rhizobium sp. strain T-37 and QF, were tolerant to paraquat until100 ppm, but other strains were sensitive to paraquat, especially at high concentration.Quantitative examination to the sensitive strains shows that higher concentration of paraquat caused higher toxicity to the growth of Rhizobium. Rhizobium sp. strain G-69 and G-182.paraquat addition at 100 ppm slightly decreased cell density from 10 to 10 CFU/mL. Rhizobium japonicum strains 143 and KS were tolerant to 20 and 40 ppm of paraquat; their cell density increased from 10^6 to a level of 10&7 or 10^8 CFU/mL depend on the strain. This level was not significantly lower than those in medium without paraquat, in which maximal population density reached to 10^8 or 10^9 CFU/mL. Addition of higher paraquat concentration damaged the cell of these strains, and caused population density increased specifically to a level of 10^1 CFU/mL. The data which showed that paraquat was toxic to Rhizobium sp. were important growth inhibitor, because growth inhibition of these bacteria may influence the formation of root nodule on leguminous plants, and in turn will decrease the yield. Due to widely applied paraquat in agricultural and plantation systems, and the role of Rhizobium in nitrigen fixation, these results are important for minimizing the impact of paraquat application

Paraquat Toxicity on Root Nodule Formation on Macroptiliuma Tropurpureum Urb. and Its Corelation with Population of Rhizobium SP.

This study was designed to investigate the paraquat toxicity toward root nodulation by Rhizobium on Macroptilium atropurpureum as an indicator plant. The legume was grown in Thornton medium treated with several concentrations of paraquat and inoculated with R.japonicum 143 (Rj-143) or Rhizobium sp. C-1.1. These bacteria represent cross-inoculation of soybean and cover-crops legumes, respectively. Nodule formation and Rhizobium population were measured periodically. At the end of planting time, nitrogenase activity of the nodules was analysis based on ARA (Acethylene Reduction Analysis) method. The results showed that nodules in plants inoculated with Rhizobium without addition paraquat, were formed within four weeks. There was no nodulation when paraquat was added. Paraquat was toxic to the plant, causing chlorosis, stunting, drying of the plant tissues, and death. The symptoms were detected at the second week after planting time. Paraquat also decreased Rhizobium population from 10^6 to 10^2 or 10^1 CFU/mL at 40 and 100 pp, respectively. These results depicted that paraquat disturbed the plant before nodulation, and at the same time Rhizobium populatin decreased until below minimal population required for nodulation. Therefore, the process of nodulation was disturbed, and in some treatments there was nodulation. It was concluded that paraquat was toxic to both plant and the Rhizobium, which cause nodulation failure

Paraquat Herbicide in Peat Soil: I. Its Effects on the Dynamics of Microbial Population

Paraquat has been used widely and periodically in peat soil. It is stable in acid environments, therefore its application in peat soil which represents an acid environment, might prolong its persistence. Liming treatment has known to reduce peat soil acidity. This research was conducted to study the effect of paraquat and liming treatments on the dynamics of microbial population in peat soil. Unlimed and limed peat soil were treated with paraquat to a final concentration of 20 ppm, and incubated for 2 months. Microbiological analysis, consisting of counting of bacterial, actinomycetes, and fungal population were done weekly. The changes of pH value and paraquat residue were also measured. The results showed that in unlimed peat soil, paraquat treatment did not influence microbial population. However, when paraquat was added into limed peat soil, the number of microbial population decreased; especially the population of bacteria. Liming treatment increased bacterial population and changed the population dynamics of actinomycetes. No significant difference of fungal population in peat soil treated with paraquat and lime. Additionally, there was no significant difference in paraquat resistance between limed and unlimed peat soil

Acceleration of Paraquat Biodegradation by Isolated Soil Bacteria

Herbicides residues were reported to have impact on the ecosystem. It was thought that acceleration of paraquat degradation would minimize these impacts. Paraquat was persistent in peat soil due to low pH. This study was done to investigate the role of bacterial isolates on the acceleration of paraquat degradation, especially in peat soil. The bacteria were isolated from several kinds of Indonesian soils using enrichment culture technique in a modified N-free medium. The medium was added with paraquat at gradually increase-concentration from 10, 20, and 40 ppm (w/w). Examinations in paraquat degradation were done in two levels. The first was in a synthetic medium (N-free medium); the second was in soil extract medium. Two kinds of peat were used to make the soil extract media, i.e. fibric and saphric peat soils.Several bacterial isolates were able to degrade paraquat in N-free medium. However, the degradation mode was different with those in peat soil extract media. None of them degraded paraquat in fibric and saphric soil extract media. It was suggested that the environmental limiting factors were responsible to the failure of paraquat degradation. Two selected isolates were able to degrade paraquat when the pH value of the extract medium was enhanced to around 5.5. Bacterial isolate of SM1, which was isolated from acid sulfate soil of Central Kalimantan, was the best isolate which was able to degrade paraquat in synthetic medium and peat soil extract media, especially in fibric extract medium. It degraded around 30%of paraquat within 15 day. Experiments are being done to enhance paraquat degradation by inoculation of mixed cultures of selected bacterial isolates

Herbisida Parakuat dalam Lahan Gambut: II. Pengaruhnya terhadap Pertumbuhan dan Hasil Kedelai

Utilization of peat soil for agriculture faces several constraints, such as low soil fertility and pH value. No-tillage agricultural system in peat land needs application of herbicides, for example herbicides with paraquat as active agent. This research was conducted to study the influence of paraquat on the growth and yield of soybean in peat. Peat soil from Central Kalimantan Province was obtained for this study. Due to the requirement of the plant, the soil was treated with lime and NPK-fertilizers. The results showed that paraquat significantly inhibited vegetative growth and decreased soybean production. These phenomena were found in early and advanced decomposed peat soil. Enhancement of vegetative growth and yield were detected when peat was treated with lime and or fertilizers. Liming treatment also supported the formation of root nodules. Inspite of increasing the growth of soybean, lime and fertilizers addition in peat was able to neutralize the negative effect of paraquat on the growth and yield of soybean. The best growth and yield of soybean were found in early decomposed peat soil, i.e. fibric peat soil