Judul: Penapisan Bakteri Asam Laktat Penghasil Bioetanol pada Substrat Cairan Hidrolisat Rumput Laut Gracilaria sp.
Abstrak: Bakteri asam laktat (BAL) berpotensi mengkonversi gula menjadi asam laktat dan etanol. Penelitian terkait fermentasi bioetanol pada substrat cairan hidrolisat Gracilaria sp. menggunakan BAL belum dilakukan. Penelitian ini bertujuan mengkarakterisasi komposisi kimia tepung dan cairan hidrolisat Gracilaria sp., menyeleksi hasil penapisan BAL penghasil bioetanol, serta produksi bioetanol pada fermentasi hidrolisat menggunakan BAL terpilih dan Saccharomyces cerevisiae yang telah diadaptasikan. Tepung Gracilaria sp. mengandung kadar agar yang tinggi serta kadar lignin yang rendah. Kandungan gula pada cairan hidrolisat Gracilaria sp. meliputi glukosa (29,58±4,89 g/L) dan galaktosa (24,58±2,44 g/L). Hasil penapisan menunjukkan bahwa bakteri Pediococcus pentosaceus BP(20) terdeteksi menghasilkan bioetanol tertinggi pada fermentasi substrat de Man Rogosa Sharpe Broth (MRSB). Fermentasi cairan hidrolisat Gracilaria sp. oleh P. pentosaceus BP(20) tidak menghasilkan bioetanol, sedangkan fermentasi oleh S. cerevisiae pada substrat yang sama menghasilkan konsentrasi tertinggi (25,65 g/L) selama fermentasi 72 jam.
Keyword: Bakteri Asam Laktat, Bioetanol, S. cerevisiae

Judul: Produksi Bioetanol Pada Substrat Hidrolisat Limbah Padat Karaginan Menggunakan Bakteri Asam Laktat dan Saccharomyces cerevisiae.
Abstrak: Limbah padat karaginan (LPK) memiliki potensi sebagai bahan baku bioetanol. Produksi bioetanol oleh Saccharomyces cerevisiae telah banyak dilakukan, sedangkan produksi bioetanol oleh bakteri asam laktat (BAL) masih sangat jarang dilakukan. Penelitian ini bertujuan untuk: 1) menentukan karakterik hidrolisat limbah padat karaginan (LPK) sebagai bahan baku bioetanol; 2) melakukan penapisan BAL untuk produksi bioetanol; dan 3) memproduksi bioetanol menggunakan S. cerevisiae dan BAL. Penelitian ini diawali dengan pembuatan hidrolisat menggunakan hidrolisis asam. Hidrolisat ini digunakan sebagai bahan baku produksi bioetanol menggunakan S. cerevisiae dan BAL. Sebelum itu dilakukan penapisan BAL penghasil bioetanol menggunakan media MRSB. Hidrolisat LPK mengandung gula pereduksi 2,1% (w/v), glukosa (568,01 mg/L) dan galaktosa (1,19 mg/L). Bakteri terpilih pada penapisan BAL penghasil bioetanol menggunakan media MRSB adalah Pediococcus pentosaceus BP (8). Produksi bioetanol yang dihasilkan oleh S. cerevisiae pada media hidrolisat LPK tertinggi pada jam ke-48 (7,78 g/L). Pediococcus pentosaceus BP (8) tidak dapat memproduksi bioetanol pada hidrolisat LPK.
Keyword: Bakteri asam laktat, bioetanol, hidrolisis, limbah padat karaginan

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