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Genomics of PHA Synthesizing Bacteria
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Parveen K. Sharma, Jilagamazhi Fu, Nisha Mohanan, David B. Levin
Glycerol uptake in Pseudomonas species is mediated by glycerol “uptake facilitators,” which are integral membrane proteins (glpF, locus tag PPUTLS46_022196 in the P. putida LS46 genome), catalyzing the rapid equilibration of glycerol concentration gradients across the cytoplasmic membrane [65]. Glycerol is converted to glycerol-3-phosphate (G3P) by phosphorylation of glycerol by the ATP-dependent glycerol kinase (glpK, locus tag PPUTLS46_022201 in P. putida LS46), followed by the dehydrogenation of G3P into dihydroxyacetone phosphate (DHAP) by three glyceraldehyde-3-phosphate dehydrogenase (GPDHs: locus tags PPUTLS46_022211, PPUTLS46_005991, and PPUTLS46_012690 in P. putida LS46). Glycerol is not a preferential carbon source for PHA production, and about two-thirds of the glycerol added to the medium as the sole carbon source for mcl-PHA production remained unused by P. putida LS46 after 72 h [66]. Phosphorylation of glycerol by GK is the rate-limiting step. GK, along with glycerol-3-phosphate dehydrogenase (GlpD), is induced by the presence of glycerol under aerobic conditions.
Tailoring Triacylglycerol Biosynthetic Pathway in Plants for Biofuel Production
Published in Arindam Kuila, Sustainable Biofuel and Biomass, 2019
Kshitija Sinha, Ranjeet Kaur, Rupam Kumar Bhunia
The first step of mobilization is hydrolysis of TAG to free fatty acids and glycerol, which is triggered by a lipase called sugar-dependent-1 (SDP-1) in plants. It belongs to the same gene family which consists of the lipases that initiate the hydrolysis of TAG in other organisms such as mammals, insects, and yeasts. The glycerol that is released here is converted into dihydroxyacetone phosphate (DHAP) via the action of glycerol kinase (GLI-1) located in the cytosol and flavin adenine dinucleotide-linked G-3-P dehydrogenase (SDP-6) located in the inner mitochondrial membrane. This DHAP can now be converted into sugars by gluconeogenesis (Quettier et al. 2009).
Transport of Nutrients and Carbon Catabolite Repression for the Selective Carbon Sources
Published in Kazuyuki Shimizu, Metabolic Regulation and Metabolic Engineering for Biofuel and Biochemical Production, 2017
Dihydroxyacetone is then phosphorylated by a kinase using ATP (Fig. 8). Another pathway for glycerol utilization is that glycerol is phosphorylated by glycerol kinase (ATP: glycerol phosphotransferase, EC 2.7.1.30) to form L-glycerol 3-phosphate (GL3P), which then is converted to glyceraldehyde 3-phosphate (GAP) in the glycolysis.
Effect of carbohydrate ingestion during cycling exercise on affective valence and activation in recreational exercisers
Published in Journal of Sports Sciences, 2018
Vivian Lee, Kay Rutherfurd-Markwick, Ajmol Ali
The glucose concentration was analysed by the hexokinase method, total cholesterol concentration by cholesterolesterase/cholesteroloxidase/peroxidase method, HDL-C concentration by detergent/cholesterolesterase/cholesteroloxidase/peroxidase method and triglyceride by lipase/glycerol kinase method according to the manufacturer’s instructions from Roche. The low-density lipoprotein (LDL-C) was calculated by subtracting the HDL-C concentration by the total cholesterol concentration. For all biochemical indices, there was a <5% intra-assay and <5% inter-assay coefficient of variation.
Utilization of glycerol and crude glycerol for polysaccharide production by an endophytic fungus Chaetomium globosum CGMCC 6882
Published in Preparative Biochemistry and Biotechnology, 2019
Zichao Wang, Tao Ning, Kun Gao, Xiaojia He, Huiru Zhang
As shown in Fig. 2C,D, the spore morphology of C. globosum CGMCC 6882 was found more favorable for polysaccharide production, this was similar to the general rules of microbial exo-polysaccharide synthesis, the exo-polysaccharide was synthesized during the stationary period for microorganism to protect it against environmental pressures.[16] The synthesis of biomass by C. globosum CGMCC 6882 from glycerol mainly through the pathways of glycerol phosphorylated to glycerol-3-phosphate by glycerol kinase, glycerol-3-phosphate oxidized to dihydroxyacetone phosphate by aerobic glycerol-3-phosphate dehydrogenase, dihydroxyacetone phosphate, and glyceraldehyde-3-phosphate aldolase to fructose-1,6-biphosphatase by fructose-1,6-biphosphatase aldolase, these pathways consumed a lot of energy,[17] meanwhile, the possible osmotic stress induced by glycerol made the mycelial cells more dispersed.[18] These might be the reason for long cell growth time, spore morphology, low cell dry weight, and high polysaccharide titer when C. globosum CGMCC 6882 used glycerol for polysaccharide production. When glucose was used as the sole carbon source, C. globosum CGMCC 6882 grew faster and easily formed large mycelia pellet and long hypha (Fig. 2A,B), thus leading to high cell dry weight and low polysaccharide titer. Interestingly, many researchers obtained similar results to this study, for instance, Lv et al.[19] and Chen et al.[20] found that the high production of Monascus pigments from Monascus species was associated with the formation of freely dispersed small mycelia pellets and short hyphae. Meanwhile, Driouch et al.[21] demonstrated that when titanate micro-particles were added into the growth medium, the pellet size of Aspergillus niger decreased from 1.7 to 0.3 mm, but the enzyme titer of glucoamylase produced by A. niger was 9.5-fold compared to the control group.
Mutagenesis of echinocandin B overproducing Aspergillus nidulans capable of using starch as main carbon source
Published in Preparative Biochemistry & Biotechnology, 2020
Zhong-Ce Hu, Wen-Jun Li, Shu-Ping Zou, Kun Niu, Yu-Guo Zheng
Generally, it is worth mentioning that microorganisms can utilize different carbon sources through different metabolism pathways. Carbon sources can often influence cell growth and metabolite production during fermentation processes. It was reported that mannitol and fructose were the traditional carbon sources for echinocandin B biosynthesis.[6] Obviously, starch is related to the metabolism of fructose and mannitol in A. nidulans, it transforms into fructose-6-phosphate under the function of glycogen phosphorylase, hexokinase and glucose-6-phosphate isomerase (Figure 2). And then fructose-6-phosphate can transform into fructose involved in the subsequent steps of glycolysis and enter mannitol cycle by mannitol-1-phosphate dehydrogenase (M1PDH) and mannitol-1-phosphatase (M1Pase).[31,32] Accordingly, starch, fructose and mannitol may have the similar metabolic processes, and can also provide enough energy for echinocandin B biosynthesis.[6] Altogether, these data provide indirect albeit support for carbon source replacement of fructose and mannitol by starch. Meanwhile, glycerol and peanut oil were also selected as carbon sources for echinocandin B fermentation. Glycerol as a kind of carbon source can be decomposed to glycerol-3-phosphate by glycerol kinase when strain is under starvation.[33] Then glycerol-3-phosphate transforms into 1, 3-diphosphoglycerate which leads to EMP pathway via dihydroxyacetone-phosphate. Using glycerol as carbon source was of benefit to mycelium growth at the beginning of fermentation. Furthermore, it was reported that glycerol might play a role in balancing the cellular osmoregulation and redox potential to regulate echinocandin B fermentation.[32,33] As we know, plant oil is also the common poor carbon source in antibiotic fermentation because it cannot be directly used by microorganisms.[3] Oil can be degraded to short-chain acyl-CoA, which can participate in biosynthesis of linoleic acid, the side chain of echinocandin B.