Judul: Eksplorasi Bakteri Amilolitik Yang Mampu Menghasilkan Polihidroksialkanoat (PHA) Sebagai Bahan Baku Bioplastik Dari Ekosistem Air Hitam Kalimantan Tenga
Abstrak: Salah satu faktor pembentuk tanah adalah organisme yang di dalamnya termasuk mikroba. Mikroba tanah mempunyai peranan yang penting dalam produktivitas tanah dan tanaman. Selain itu, mikroba tanah telah banyak dimanfaatkan dalam bidang pertanian, kesehatan, industr., pertambangan dan lingkungan. Polihidrok sialkanoat (PHA) merupakan cadangan makanan dan karbon yang diakumulasikan bakteri di dalam selnya dan bisa digunakan sebagai bahan baku plastik yang ramah lingkungan. Fenelitian ini bertujuan untuk mendapatkan isolat- isolat bakteri amilolitik (pendegradasi pati) yang mampu menghasilkan PHA sebagai bahan baku bioplastik dari ekosistem air hitam Kalimantan Tengah. Penelitian ini dilakukan di Laboratorium Mikrobiologi. Pusat Penelitian Lingkungan Hidup (PPLH). Tahapan penelitian ini meliputi isolasi bakteri dari sampel tanah ekosistem air hitam, uji kemampuan isolat bakteri dalam mendegradasi pati, uji kemampuan iso lat bakteri dalam menghasilkan Polihidroksialkanoat (PHA), pembuatan kultur stok, karakterisasi dan identifikasi isolat terpilih. Hasil penelitian didapatkan sebanyak 23 isolat bakteri pendegradasi pati yang mampu menghasilkan PHA di dalam selnya. Dua puluh tiga isolat tersebut mampu mendegradasi pati dengan indikasi adanya zona terang di sekitar koloni sclnya yang diamati secara langsung dan diwarnai dengan larutan lodium, Gram Uji kemampuan akumulasi PHA 23 isolat tersebut dilakukan dengan pewarnaan Sudan Black B, xylene dan safranin, dengan indikasi adanya granul yang berwarna kehitaman atau kebiruan di dalam sel bakteri ketika diamati di bawah mikroskop dengan perbesaran 1000x. ...
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Judul: Isolation and Screening of PHA Producing Halotolerant Actinobacteria from High Salinity Environment
Abstrak: Plastik konvensional menjadi masalah lingkungan yang genting dihadapi oleh umat manusia akibat dari persistensinya di lingkungan hidup. Hal ini menyebabkan pencarian alternatif terhadap plastik tersebut menjadi sebuah urgensi. Salah satu alternatifnya yaitu polihidroksialkanoat (PHA), biopolimer termoplastik yang dapat disintesis oleh beragam jenis bakteri sebagai cadangan energi termasuk aktinobakteri yang merupakan salah satu filum terbesar di kelompok bakteri. Biaya produksi yang tinggi dari polihidroksialkanoat mengarahkan eksplorasi terhadap mikroorganisme halotoleran (ekstremofil) sebagai sumber produk. Oleh karena itu, penelitian ini bertujuan mengisolasi aktinobakteri halotoleran penghasil polihidroksialkanoat (PHA). Isolat-isolat yang digunakan diisolasi dari berbagai lingkungan bersalinitas tinggi di Indonesia. Setelah dimurnikan isolat-isolat yang didapatkan kemudian ditumbuhkan pada media induksi ISP9-I dan ditapis dengan menggunakan zat warna Sudan Black B dan Nile Red. Polimer yang diekstraksi dari isolat yang positif kemudian dikuantifikasi dan divalidasi menggunakan analisis gravimetrik dan uji asam krotonat. Analisis gravimetrik menunjukkan produktivitas PHA oleh isolat HVB mencapai 78,426%, sedangkan uji asam krotonat memvalidasi dan menunjukkan hasil 1,982% poli(3-hidroksibutirat) (P3HB) yang mengindikasikan tipe heteropolimer., Conventional plastics have become an urgent environmental problem for human due to their persistence in the environment. This issue has led to the exploration of alternatives. One of them is polyhydroxyalkanoates (PHA), a thermoplastic biopolymer synthesized by various bacteria as an internal energy storage compound, including actinobacteria, one of the largest Gram-positive bacteria phylum. However, the high production cost of PHA is a significant factor contributing to its non-competitiveness in the market. This has led to the exploration of halotolerant bacteria (extremophiles) as a potential producer of PHA. Therefore, this study aims to isolate indigenous PHA producer halotolerant actinobacteria. The actinobacteria used in this study were isolated from various high-salinity environments in Indonesia. After purification, isolates were cultured in ISP9-I broth media and screened by using Sudan Black B and Nile Red dyes. The extracted polymer from both positive screenings was then quantified and validated using gravimetric analysis and crotonic acid assay. The analysis showed PHA productivity by HVB can reach up to 78,426% of the dry cell weight, whereas the crotonic acid assay showed 1,982% of the extract is poly(3-hydroxybutyrate) (P3HB), indicating that extracted the polymer is a heteropolymer.
Keyword: extremophiles, Gram positive, PHA, plastic, P3HB

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