title: Microbial biosynthesis and secretion of l-malic acid and its applications.
abstract: l-Malic acid has many uses in food, beverage, pharmaceutical, chemical and medical industries. It can be produced by one-step fermentation, enzymatic transformation of fumaric acid to l-malate and acid hydrolysis of polymalic acid. However, the process for one-step fermentation is preferred as it has many advantages over any other process. The pathways of l-malic acid biosynthesis in microorganisms are partially clear and three metabolic pathways including non-oxidative pathway, oxidative pathway and glyoxylate cycle for the production of l-malic acid from glucose have been identified. Usually, high levels of l-malate are produced under the nitrogen starvation conditions, l-malate, as a calcium salt, is secreted from microbial cells and CaCO3 can play an important role in calcium malate biosynthesis and regulation. However, it is still unclear how it is secreted into the medium. To enhance l-malate biosynthesis and secretion by microbial cells, it is very important to study the mechanisms of l-malic acid biosynthesis and secretion at enzymatic and molecular levels.
authors.affiliation: a UNESCO Chinese Center of Marine Biotechnology , Ocean University of China , Qingdao , China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Chi
authors.affiliation: a UNESCO Chinese Center of Marine Biotechnology , Ocean University of China , Qingdao , China.
authors.forename: Zhi-Peng
authors.initials: ZP
authors.lastname: Wang
authors.affiliation: a UNESCO Chinese Center of Marine Biotechnology , Ocean University of China , Qingdao , China.
authors.forename: Guang-Yuan
authors.initials: GY
authors.lastname: Wang
authors.affiliation: a UNESCO Chinese Center of Marine Biotechnology , Ocean University of China , Qingdao , China.
authors.forename: Ibrar
authors.initials: I
authors.lastname: Khan
authors.affiliation: a UNESCO Chinese Center of Marine Biotechnology , Ocean University of China , Qingdao , China.
authors.forename: Zhen-Ming
authors.initials: ZM
authors.lastname: Chi
mesh_terms: D001419:Bacteria / Q000166:cytology / Q000378:metabolism*; D005285:Fermentation; D019649:Food Industry; D005649:Fumarate Hydratase / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D006868:Hydrolysis; D008293:Malates / Q000737:chemistry / Q000378:metabolism*
chemical_list: D006038:Glyoxylates; D008293:Malates; C030298:malic acid; D005649:Fumarate Hydratase; D005947:Glucose; C031150:glyoxylic acid
keywords: Application; biosynthesis; fumurase; l-malic acid; one-step fermentation secretion