Judul: Observation on Bioplastic Degradation by  River Microbial Communities
Abstrak: Plastik merupakan polimer polietilen yang rekalsitran karena ikatan kimianya tidak mudah diuraikan oleh kebanyakan mikrob pengurai. Produksi sampah plastik yang tinggi menyebabkan penumpukan hingga pencemaran air atau tanah oleh sampah plastik. Hal ini dapat diminimalkan dengan metode penguraian sampah berbasis biologi menggunakan bakteri pendegradasi plastik yang ramah lingkungan dan ekonomis. Penelitian ini bertujuan memperoleh bakteri untuk mempercepat proses degradasi plastik oleh komunitas mikrob asal air sungai. Metode yang digunakan dalam penelitian ini meliputi pengambilan sampel air dan lumpur dari Sungai Ciliwung, Sungai Cisadane, dan Sungai Ciapus, pengamatan degradasi bioplastik, pengayaan bakteri pendegradasi plastik, isolasi bakteri pendegradasi plastik dan uji degradasi plastik. Hasil penelitian menunjukkan degradasi terdapat pada seluruh sampel bioplastik. Penambahan pupuk NPK menghasilkan proses degradasi pada bioplastik lebih cepat. Sebanyak 15 isolat bakteri diperoleh dari seluruh sampel dan dapat mendegradasi plastik. Proses biodegradasi dilakukan oleh sekolompok bakteri, bukan koloni tunggal., Plastics are recalcitrant polyethylene polymers because their chemicals are not easily broken down by most decomposers. The high production of plastic waste causes the accumulation of air or soil pollution by plastic waste. This can be minimized by a biological-based waste decomposition method using plastic degrading bacteria that is environmentally friendly and economical. This study aims to obtain bacteria to support the plastic degradation process by microbes from river water. The methods used in this study include taking samples of water and mud from the Ciliwung River, Cisadane River, and Ciapus River, observing bioplastic degradation, enriching plastic-degrading bacteria, isolating plastic degrading bacteria and testing plastic degradation. The results showed some degree of degradation in all bioplastic samples. The addition of NPK fertilizer made the degradation process of bioplastics run faster. 15 different bacterial isolates were obtained from all samples and could degrade plastics. The biodegradation process is carried out by groups of bacteria, not single colonies.
Keyword: Bacteria, Biodegradation, Bioplastic, River

Judul: Penentuan Laju Biodegradasi Bioplastik dari Tandan Kosong Kelapa Sawit pada Lingkungan Alami dan Terkontrol
Abstrak: Plastik dari minyak bumi sangat sulit terdegradasi di alam dan menyebabkan terjadinya pencemaran lingkungan. Salah satu alternatif untuk mengurangi sampah plastik yaitu dengan memproduksi plastik yang ramah lingkungan. Bioplastik merupakan plastik yang dapat terdegradasi dan terbuat dari bahan terbaharui. Bioplastik dapat digunakan layaknya plastik konvensional dan dapat terurai oleh aktivitas mikroorganisme. Komponen yang digunakan harus material yang dapat diuraikan oleh mikroba. Beberapa penelitian telah menghasilkan teknologi pembuatan bioplastik salah satunya bioplastik dari tandan kosong kelapa sawit (TKKS) yang menggunakan selulosa sebagai bahan dasarnya. Bioplastik yang digunakan pada penelitian ini berbahan dasar TKKS. Penelitian yang dilakukan bertujuan untuk mengetahui kemampuan biodegradasi bioplastik dari TKKS melalui lingkungan terkontrol maupun alami dan dibandingkan dengan plastik oxodegradable, bioplastik dari pati, dan plastik konvensional. Penelitian ini dilakukan 4 tahap, yaitu: 1) Karakterisasi media pendegradasi meliputi total C/N rasio, pH, total mikroorganisme. 2) Pengujian biodegradasi pada lingkungan alami (media tanah perkebunan dan tanah Tempat Pembuangan Akhir (TPA)) dengan menggunakan rangkaian alat biometer. 3) Pengujian biodegradasi pada lingkungan terkontrol dengan menggunakan metode ISO 18455-2. Pengujian tahap kedua dan ketiga dilakukan dengan cara perhitungan CO2 yang dihasilkan selama proses penguraian. 4) Melakukan pengamatan visual pertumbuhan mikroorganisme. Bioplastik yang dihasilkan dapat tergolong sebagai plastik ramah lingkungan jika mudah atau dapat terdegradasi. Hasil biodegradasi dengan metode lingkungan alami menggunakan alat biometer pada media tanah perkebunan yang dihasilkannya oleh bioplastik dari TKKS, bioplastik dari pati, oxodegradable plastic, dan plastik konvensional menghasilkan nilai total CO2 berturut-turut sebesar 8,8 mg; 7,7 mg; 5,28 mg dan 0,00 mg dengan nilai rata-rata laju biodegradasi secara berturut-turut sebesar 0,20 mg/hari; 0,17 mg/hari; 0,12 mg/hari dan 0,00 mg/hari. Sedangkan nilai total CO2 pada media tanah TPA secara berturutturut sebesar 3,63 mg; 3,19 mg; 2.86 mg; 0,00 mg dengan nilai rata-rata laju biodegradasi 0,09 mg/hari; 0,08 mg/hari; 0,07 mg/hari, 0,00 mg/hari. Pada lingkungan terkontrol menggunakan metode ISO 14855-2, bioplastik dari TKKS mampu terdegradasi lebih cepat yaitu 32 hari dengan laju biodegradasi 3,34 %/hari dari pada bioplastik dari pati yang terdegradasi 50 hari dengan laju 1,77 %/hari. Sedangkan pada oxodegradable plastic dan plastik konvensional sampai 60 hari tidak dihasilkan CO2 sehingga dapat diasumsikan bahwa kedua bahan tersebut tidak dapat terdegradasi secara biologis (biodegradasi).
Keyword: Bioplastik, biodegradasi, tandan kosong kelapa sawit (TKKS), ISO 14855-2, plastik ramah lingkungan

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite