Judul: Pemanfaatan Zeolit Terimpregnasi Logam Sebagai Katalis Konversi Glukosa Menjadi 5-Hidroksimetilfurfural (HMF)
Abstrak: The abundant glucose content of biomass needs to be re-optimized, one of which is synthesizing 5-hydroxymethylfurfural (HMF). HMF can be synthesized through glucose with the help of a catalyst. That used consists of homogeneous and heterogeneous catalysts. Homogeneous catalysts such as H2SO4 can be used, but they can cause corrosion of the tool. Heterogeneous catalysts such as zeolite can be an alternative catalyst for the HMF formation process. This formation happens because it is easy to regenerate, and zeolites has Lewis acid sites and Brönsted acids That is a reason that zeolite is a potential catalysts. This study was conducted to provide a review related to the conversion of glucose into HMF, analyze, and compare the characteristics of zeolites that affect the process of forming HMF from glucose. Metal impregnation in zeolite aims to increase the acidity of the zeolite and assist in the isomerization of glucose to fructose. The results obtained indicate an effect of zeolite characteristics on the formation of HMF. The Si/Al ratio with a value of 11 is the optimum Si/Al ratio for the formation of HMF. In addition, there is also the influence of temperature and time on the process of forming the zeolite, Kandungan glukosa yang melimpah dari biomassa perlu dioptimalkan kembali pemanfaatannya salah satunya dengan pembuatan 5-hidroksimetilfurfural (HMF). HMF dapat disintesis melalui glukosa dengan bantuan katalis yang terdiri atas katalis homogen dan heterogen. Katalis homogen seperti H2SO4 dapat digunakan, namun penggunaannya dapat menyebabkan korosi pada alat. Katalis heterogen seperti zeolit dapat menjadi alternatif untuk proses pembentukan HMF. Hal ini terjadi karena sifatnya yang mudah diregenerasi, selain itu zeolit memiliki situs asam Lewis dan asam Brönsted yang potensial untuk dimanfaatkan sebagai katalis. Penelitian dilakukan untuk memberikan ulasan terkait konversi glukosa menjadi HMF, serta menganalisis dan membandingkan karakteristik zeolit yang mempengaruhi proses pembentukan HMF dari glukosa. Impregnasi logam pada zeolit bertujuan meningkatkan keasaman pada zeolit dan juga dapat membantu tahapan isomerasi glukosa menjadi fruktosa. Hasil yang diperoleh menunjukkan bahwa terdapat pengaruh karakteristik zeolit terhadap pembentukan HMF. Rasio Si/Al dengan nilai 11 merupakan rasio Si/Al yang optimum untuk pembentukan HMF. Selain itu juga terdapat pengaruh suhu dan waktu pada proses pembentukan zeolit tersebut.
Keyword: 5-hydroxymethylfurfural, impregnation, mordenite zeolite, Si/Al ratio

Judul: Transformation of Glucose into 5-Hydroxymethylfurfural Using Natural Cr-Zeolite Catalyst in Biphasic Solvent System
Abstrak: Zeolit merupakan katalis heterogen yang dapat digunakan dalam transformasi gula menjadi 5-hidroksimetilfurfural (HMF) karena memiliki situs asam Lewis dan asam Brønsted. Zeolit alam dapat dimanfaatkan sebagai katalis, namun zeolit alam memiliki aktivitas katalitik yang rendah jika dibandingkan dengan zeolit sintetis. Oleh karena itu, aktivitas katalitik ditingkatkan dengan pengembanan logam Cr yang juga meningkatkan keasaman zeolit. Penelitian ini bertujuan menganalisis potensi zeolit alam termodifikasi ion logam Cr sebagai katalis heterogen dalam sistem pelarut bifasik untuk transformasi glukosa menjadi HMF dan menganalisis pengaruh rasio Si/Al dalam transformasi glukosa menjadi HMF melalui kajian literatur. Pengembanan logam Cr ke dalam zeolit dapat meningkatkan aktivitas katalitik sehingga rendemen HMF yang didapatkan lebih tinggi. Rasio Si/Al yang lebih tinggi mampu memberikan rendemen HMF yang lebih tinggi. Pelarut memiliki peran penting dalam sintesis HMF. Penggunaan sistem pelarut bifasik mampu mengatasi sulitnya proses pemisahan pada senyawa murni dan dapat meningkatkan rendemen HMF., Zeolite is a heterogeneous catalyst that can be used to the transformation of sugar into 5-hydroxymethylfurfural (HMF) because it has Lewis and Brønsted acid sites. Natural zeolite can be used as a catalyst, but natural zeolite has low catalytic activity compared to synthetic zeolite. Therefore, the catalytic activity is enhanced by the impregnation of Cr metal which also increases the acidity of zeolite. This study aims to analyze the potential of Cr metal ion-modified natural zeolite as a heterogeneous catalyst in a biphasic solvent system for the transformation of glucose into HMF and analyze the effect of the Si/Al ratio in the transformation of glucose into HMF through a literature review. The impregnation of Cr into the zeolite can increase the catalytic activity so that the yield of HMF obtained is high. A higher Si/Al ratio can provide a higher HMF yield. Solvents have an important role in the synthesis of HMF. The use of a biphasic solvent system can overcome the difficulty of the separation process in pure compounds and can increase the yield of HMF.
Keyword: biphasic systems, chromium, 5-hydroxymethylfurfural, zeolite

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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