Investigation of the Physiology of the Obligate Alkaliphilic Bacillus marmarensis GMBE 72T Considering Its Alkaline Adaptation Mechanism for Poly(3-hydroxybutyrate) Synthesis

Abstract

The novel extreme obligate alkaliphilic Bacillus marmarensis DSM 21297 is known to produce polyhydroxybutyrate (PHB). However, the detailed mechanism of PHB synthesis in B. marmarensis is still unknown. Here, we investigated which metabolic pathways and metabolic enzymes are responsible for PHB synthesis in order to understand the regulatory pathway and optimize PHB synthesis in B. marmarensis. In accordance with the fact that beta-galactosidase, 3-hydroxyacyl-CoA dehydrogenase, and Enoyl-CoA hydratase together with acyl-CoA dehydrogenase and lipase were annotated in B. marmarensis according to the RAST server, we used glucose, lactose, and olive oil to understand the preferred metabolic pathway for the PHB synthesis. It was found that B. marmarensis produces PHB from glucose, lactose, and olive oil. However, the highest PHB titer and the highest amount of PHB synthesized per dry cell mass (YP/X) were achieved in the presence of lactose, as compared to glucose and olive oil. Additionally, in the absence of peptone, the amount of PHB synthesized is reduced for each carbon source. Interestingly, none of the carbon sources studied yielded an efficient PHB synthesis, and supplementation of the medium with potassium ions did not enhance PHB synthesis. According to these experimental results and the presence of annotated metabolic enzymes based on the RAST server, PHB accumulation in the cells of B. marmarensis could be improved by the level of the expression of 3-hydroxybutyryl-CoA dehydrogenase (1.1.1.157), which increases the production of NADPH. Additionally, the accumulation of 3-hydroxyacyl-CoA could enhance the production of PHB in B. marmarensis in the presence of fatty acids. To our knowledge, this is the first report investigating the regulatory system involved in the control of PHB metabolism of B. marmarensis.

Screening, identification and characterisation of Polyhydroxybutyrate producing bacteria from garden soil

“…The concentration of the test sample was estimated by comparing with a standard. From these results, the potent PHB strain was identi ed [44].…”

Challenges for polyhydroxyalkanoates production: extremophilic bacteria, waste streams, and optimization strategies

“…18 Haloalkalophilic microorganisms offers several advantages in in the production of PHA, easy recovery, and lower cost compared to other extremophiles. 39 For instance, the production of PHB was carried out using an alkaliphilic strain, Bacillus marmarensis DSM 21297, 70 and an acidophilic bacterium was used in another study. 71 Halophiles PHA-producer such as Haloferax mediterannei 72 and halophilic marine bacteria Vibrio proteolyticus 73 were operated in unsterilized conditions.…”

Coproduction of 5-Aminovalerate and δ-Valerolactam for the Synthesis of Nylon 5 From L-Lysine in Escherichia coli

“…The monomers of polyamides are primarily dicarboxylic acids, diamines, lactams, and ω-amino acids ( Radzik et al, 2019 ). Examples of these main platform chemicals range from succinate ( Zhang et al, 2009 ), glutarate ( Zhao et al, 2018 ), to adipate ( Wang F. et al, 2020 ) for dicarboxylic acids; from putrescine, cadaverine ( Rui et al, 2020 ; Xue et al, 2020 ), to 1,6-hexanediamine for diamines; from δ-valerolactam ( Zhang et al, 2017a ), to ε-caprolactam ( Thompson et al, 2020 ) for lactams; from 3-hydroxybutyrate ( Atakav et al, 2021 ; Mierziak et al, 2021 ; Schmid et al, 2021 ), 2-hydroxybutyrate ( Tian et al, 2021 ), to 3-hydroxyhexanoate ( Harada et al, 2021 ) for hydroxyl acids; and from 4-aminobutyrate, 5AVA ( Cheng et al, 2021b ), to 6-aminocaproate ( Turk et al, 2016 ) for ω-amino acids. In this respect, also 5AVA ( Adkins et al, 2013 ) and δ-valerolactam ( Xu et al, 2020 ) are attractive C5 platform chemicals for the production of biopolyamides from renewable biomass.…”