JoSSED 2(1) (2021) Journal of Science and Science Education http://jppipa.unram.ac.id/index.php/jossed/index ___________ Email: megahati71@gmail.com (*Corresponding author) Copyright © 2021Author et al.. This open access article is distributed under a (CC-BY License) Thermozyme Amylase from Enterobacter sp Extremophiles in Bioethanol Production Gustina Indriati 1 , Ruth Rize Paas Megahati S. 2* 1 Hiperkes and Work Safety Study Program, STIKES Indonesia, Padang, West Sumatra, Indonesia 2 Biology Department STKIP PGRI Sumatera Barat, Padang, West Sumatra, Indonesia DOI: 10.29303/jossed.v2i1.698 Article Info Received : January 25 th , 2021 Revised : April 10 th , 2021 Accepted: April 21th, 2021 Abstract: Bioethanol is an alternative fuel to replace fossil fuels due to the reduction of fossil fuels. Bioethanol is produced from starch and converted to sugar by thermozyme amylase. Thermozyme amylase produced by thermophile bacteria can be obtained from Pariangan hot springs which have a temperature of 55 °C, pH of 9.2, and have a high level of bacterial diversity. The aim of this study was to obtained isolates of thermozyme amylase-producing bacteria that have the potential for bioethanol production. The research method were bacteria isolation, amylase stability test, temperature and pH optimization, and bioethanol production. The result showed that Enterobacter sp has been isolated from Pariangan hot springs is stable up to 5 hours of incubation, temperature and pH optimum was 85 °C, pH 8.5, and fructose as a carbon source. Thermozyme amylase converts starch into sugar under optimum conditions with a yield of 9.8% bioethanol. Keywords: amylase; bioethanol; extremophiles; Enterobacter sp; Pariangan Hot Spring Citation: Indriati, G., & Megahati, R. (2021). Thermozyme Amylase from Enterobacter sp Extremophiles in Bioethanol Production. Journal of Science and Science Education, 2(1), 1-7. doi:https://doi.org/10.29303/jossed.v2i1.698 Introduction Amylase produced by bacteria or bacteria amylase is an enzyme that can hydrolyze starch to sugar (Megahati et al 2017). Amylase can convert starch to sugar in bioethanol production. Bioethanol is a biofuel that is renewable and environmentally friendly (Fatoni, & Zulfahair. 2012). Bioethanol is an alternative fuel to replace fossil fuels due to the reduction of fossil fuels (Svetlitchnyi et al., 2013). Bioethanol is used as a gasoline mixture to become biofuel. The composition of bioethanol in gasoline in the world has 5% in 2020 and increased by 20% in 2025. Generally, bioethanol is produced from starch and converted to sugar by thermozyme amylase. As a thermozyme, amylase generally does not undergo denaturation and is active at high temperatures and is very stable at normal temperatures (Schiraldi, & Rosa, 2002). Thermozyme amylase is one of the three largest industrial group enzymes and accounts for approximately 65% of the world enzyme (Abdullah et al, 2014). Thermophile bacteria are commonly found in volcanic craters, craters on the ocean floor, and hot springs. Some hot springs in Indonesia generally have a pH of 7 or even below 7 or are acidic. In contrast to the Pariangan hot springs which have a temperature of 47 ºC-51 °C and a pH of 9.2. This causes Pariangan hot springs to have a high level of bacteria diversity. The aim of this study was to obtained isolates of thermozyme amylase-producing bacteria that have the potential for bioethanol production. Bioethanol as a biofuel is needed as an alternative fuel to reduce the use of fossil fuels. Bioethanol can be obtained by utilizing the potency of thermophile amylase-producing bacteria which will be carried out in this study. The success of this research is a finding/innovation that can be applied in the development and development of science and technology.