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Pseudomonas putida
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Maria Tsampika Manoli, Natalia Tarazona, Aranzazu Mato, Beatriz Maestro, Jesús M. Sanz, Juan Nogales, M. Auxiliadora Prieto
The de novo fatty acid intermediates are activated by the acyl carrier protein (ACP). The fatty acid synthesis starts with the acetyl-CoA carboxylation into malonyl-CoA by the acetyl-CoA carboxylase, the AccABCD complex [81]. Then, the malonyl-CoA is transesterified into malonyl-ACP by the malonyl-CoA: ACP transacylase, FabD [82]. The generated malonyl-ACP is further condensed into 3-ketoacyl-ACP by different 3-ketoacyl-ACP synthases. First, it is condensed by an acetyl-CoA molecule by FabH, then, in successive rounds of elongation, a new molecule of malonyl-ACP is condensed with the 3-acyl-ACP formed by FabB or FabF [83,84]. FabB has also been proposed to catalyze the decarboxylation of malonyl-ACP into acetyl-ACP [85]. The following step includes the reduction of 3-ketoacyl-ACP into (R)-3-hydroxyacyl-ACP by a 3-ketoacyl-ACP reductase, FabG [86], and the formation of a double bond into enoyl-ACP by 3-hydroxyacyl-ACP dehydratase, FabA, or FabZ [87]. Finally, one enoyl-ACP reductase, FabI, FabK, or FabL transforms the enoyl-ACP into 3-acyl-ACP [88]. The gene that codifies for enoyl-ACP reductase activity has not been identified in P. putida KT2440 [84].
Characterization of recycled concrete aggregates
Published in François de Larrard, Horacio Colina, Concrete Recycling, 2019
S. Rémond, J.M. Mechling, R. Trauchessec, E. Garcia-Diaz, R. Lavaud, B. Cazacliu
Chemical methods are based on the selective dissolution of the ACP. Solutions of hydrochloride acid allow for an efficient dissolution of ACP and have been used in several studies (Yagishita et al. 1994; Nagataki et al. 2004). This method permits to measure the ACP content (and not only the AM content), but it is not suitable for RA coming from concretes containing calcareous aggregates, which are also partly dissolved in hydrochloric acid.
Exploring the potential of microalgae cell factories for generation of biofuels
Published in Biofuels, 2023
Dixita Chettri, Ashwani Kumar Verma, Anil Kumar Verma
In addition to conventional engineering methods, in-silico approaches have shown great potential for biofuel production from algae. In silico metabolic engineering allows deciphering the function of various genes, metabolites, enzymes, and transcripts responsible for metabolic processes. Manipulation of TAG synthesis in C. reinhardtii (Cr) for biofuel production was performed in a study using protein–protein interactions. The study showed that protein–protein interactions between thioesterases (TEs) and fatty acid acyl carrier protein (ACP) play a crucial role in fatty acid biosynthesis. Structural simulation of CrACP docking to CrTE indicated the presence of a protein–protein recognition surface between the domains. Plant TEs show similar binding to CrACP in silico as shown in the virtual screen. Activity-based cross-linking probes designed for selective detection of interactions between ACP and TE showed interaction of CrTE with CrACP with release of fatty acid. In vivo overproduction of CrTE increased total short-chain fatty acid synthesis [72].
Improvement of lipopeptide production in Bacillus subtilis HNDF2-3 by overexpression of the sfp and comA genes
Published in Preparative Biochemistry & Biotechnology, 2023
Jiawen Wang, Yuan Ping, Wei Liu, Xin He, Chunmei Du
In recent years, with the in-depth study of key enzymes and transcription factors of the lipopeptide synthesis pathway, the high production of microbial lipopeptide using more targeted genetically engineered methods has become a major research topic. The basic synthesis of lipopeptide is as follows: a branched-chain fatty acid is synthesized and activated and then connects with amino acids; the peptide chain continuously extends and finally cyclizes to form lipopeptide (Figure 1). The peptide part of the lipopeptide is synthesized in a ribosome-independent manner by complexes of non-ribosomal peptide synthetase (NRPS) enzymes.[14] NRPSs are composed of multiple multifunctional modules that cooperate with each other, and peptide extension can be performed among the modules to further extend a cycle.[15] A typical NRPS extension module consists of an adenylation (A) domain used for activating specific amino acids, a condensation (C) domain used for forming peptide bonds, and a thiolation (T) domain (i.e., peptidyl carrier protein (PCP) domain) used for delivery.[16] Acyl carrier proteins (ACPs) are key functional domains of fatty acid synthetase (FAS), which is required for the biosynthesis of the fatty acid part of the lipopeptide.[17] In Bacillus subtilis, the type II PPTase encoded by sfp gene can use for posttranslational modification of PCPs and ACPs, converting them from the inactive apo-form to the active holo-form.[18,19] Wang et al.[20] increased the iturin A production of B. amyloliquefacienss by 3.2 times, to 17.0 mg/L by overexpressing the sfp gene and knockout of kinA, bdh, dhbF and rapA. Tan et al.[21] increased the fengycin production of B. subtilis 168 that could not produce lipopeptide to 10.4 mg/L by introducing the sfp gene and replacing the original promoter of the degQ gene with the P43 promoter. Therefore, overexpression of the sfp gene is a feasible method to increase lipopeptide production.