title: Bioprocess exploration for thermostable α-amylase production of a deep-sea thermophile Geobacillus sp. in high-temperature bioreactor.
abstract: Geobacillus sp. 4j, a deep-sea high-salt thermophile, was found to produce thermostable α-amylase. In this work, culture medium and conditions were first optimized to enhance the production of thermostable α-amylase by statistical methodologies. The resulting extracellular production was increased by five times and reached 6.40 U/ml. Then, a high-temperature batch culture of the thermophile in a 15 l in-house-designed bioreactor was studied. The results showed that a relatively high dissolved oxygen (600 rpm and 15 l/min) and culture temperature of 60°C facilitated both cell growth and α-amylase production. Thus, an efficient fermentation process was established with initial medium of pH 6.0, culture temperature of 60°C, and dissolved oxygen above 20%. It gave an α-amylase production of 79 U/ml and productivity of 19804 U/l·hr, which were 10.8 and 208 times higher than those in shake flask, respectively. This work is useful for deep-sea high-salt thermophile culture, where efforts are lacking presently.
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Huang
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Hao
authors.initials: H
authors.lastname: He
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Xiangshan
authors.initials: X
authors.lastname: Zhou
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Menghao
authors.initials: M
authors.lastname: Cai
authors.affiliation: a State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , Shanghai , China.
authors.forename: Yuanxing
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D003470:Culture Media; D004795:Enzyme Stability; D005285:Fermentation; D056506:Geobacillus / Q000201:enzymology* / Q000254:growth & development; D006358:Hot Temperature; D008386:Marine Biology; D009584:Nitrogen / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D003470:Culture Media; D002244:Carbon; D000516:alpha-Amylases; D009584:Nitrogen
keywords: Geobacillus; high-temperature bioreactor; statistical methodologies; thermophile