No abstract

Plant red galangal (Alpinia purpurata K. Schum) is one of the many spices used as bio-pharmacy products which contain essential oil that is active as an antifungal and antibacterial agent. Isolation of volatile oil from red galangal rhizome (Alpinia purpurata K. Schum) uses the method of water and steam distillation so as to get the rendemen 0.1062%, the density 0.9524 g/mL and the index of refraction by 1.4862. Results from GC-MS (Gas Chromatography-Mass Spectrometry) retrieved 30 compounds contained in red galangal rhizome oil with 10 major compounds i.e. 1,8-cineole (40.92%), acetyl chavicol (10.33%), cis β-farnesene (6.91%), 1-caryophillene (6.32%), 1-β-bisabolene (3.37%), βelemene (3.23%), α-pinene (3.20%), β-sesquiphellandrene (2.32%), β-pinene (2.21%), and germacrene-D (1.90%). The inhibition test was done by agar diffusion method and different variations of concentration (1, 2, 3 and 4%) compared with ketoconazole 2% as positive controls and dimethyl sulfoxide (DMSO) as negative controls with an incubation period of 2x24 hours. The test results show that the essential oil of red galangal rhizome (Alpinia purpurata K. Schum) can inhibit the growth of the fungus Malassezia furfur with the inhibitory power on concentrations1, 2, 3 and 4% were 7.15 mm, 13.87 mm, 16.05 mm and 20.05 mm, respectively. As for comparison, ketoconazole 2% was used as positive (+) control that produces inhibitory zone 27.20 mm and dimethyl sulfoxide (DMSO) as negative control (-) which does not produce inhibitory zones.

Reclamation is an effort to repair the damaged mining sector to provide optimal benefits. This review article aims to propose a natural product technology approach to the reclamation of post-coal mining land by increasing the content of soil organic matter so that the post-mining land becomes fertile and can be used for agricultural land. The method used is an observation and literature study. Literature searches were using them ScienceDirect, Scopus, PubMed, and Google Scholar databases. Land-use change of post-mining site to agricultural land provides prospective economic value to the community. However, the land quality of the post-mining area should be improved before food crop production. Tephrosia vogelii is a member of the Papilionoideae subfamily is important for land revegetation. They can fertilize the soil because of mutualistic symbiosis with the bacteria Rhizobium sp. which is capable to fix nitrogen in the soil and hence provide available nitrogen. Thus, the use of post-mining land as agriculture can improve the economy and sustainability as well as protect life and the environment with natural product technology.

Cracking coal-forming organic compounds during the gasification process produces liquid waste containing phenolic compounds that require special handling based on their toxicity. As one of the components, there is liquid waste resulting from the coal gasification process. The purpose of this research was to study the activity of polyphenol oxidase (PPO) on phenol after the addition of Cu2+ to purple eggplant (Solanum melongena L.) extract and its potential to work more effectively in phenol biodegradation for coal wastewater containing phenol. Enzyme activity and phenol determination were carried out spectrophotometrically. The results showed PPO activity of 25.90-38.10 U/mL; 4.0 mM phenol and the activity of PPO-Cu2+ was 21.58-46.32 U/mL; 2-10 mM CuSO4; 2.0-4.0 mM phenol. Based on Michaelis Menten’s graph, the initial rate of PPO-Cu2+ was 0.015 mM/min and the initial rate of PPO was 0.15 mM/min using 2 mM phenol as a substrate. Lineweaver-Burk’s graph shows the KM of PPO-Cu2+ = 6.92 mM, which is lower than KM of PPO = 13.05 mM. Its means that the phenol response has a higher affinity for PPO-Cu2+ than PPO. The application of PPO-Cu2+ in purple eggplant extract works effectively as much as 46.7% for artificial coal liquid waste containing phenol.

NTC (Negative Temperature Coefficient) thermistors are widely used as temperature sensors in industrial and medical applications due to their high-temperature sensitivity, durability, and low cost. Generally, NTC thermistors are made from spinel structured ceramics formed by transition metal oxides with the general formula AB2O4. One of the spinel structured ceramics that can be made for NTC thermistors is NiFe2O4 nanoparticles. This work aimed to prepare Cu-Mn co-doped NiFe2O4 based thick ceramic film using Jarosite mineral as a precursor. The synthesis method used was a simple coprecipitation method, while the technique used in making a thick ceramic film was a simple screen printing technique. The sintering temperatures used were 1000 °C, 1100 °C, and 1200 °C. Based on x-ray diffraction analysis, the thick films consist of spinel phase, hematite phase, and some unidentified phase. The constant thermistor values (B) for thick films obtained with 1000, 1100, and 1200 °C sintering temperatures were 4740 K, 5669 K, and 5731 K, respectively. These results showed that all obtained thick films had passed the minimum value in market needs (B ≥2000 K).