Contributory roles of two l-lactate dehydrogenases for l-lactic acid production in thermotolerant Bacillus coagulans

Sun, Lifan; Zhang, Caili; Lyu, Pengcheng; Wang, Yanping; Wang, Limin; Yu, Bo

doi:10.1038/srep37916

Cited by 19 publications

(27 citation statements)

References 29 publications

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“…The distinct catalytic activities of L‐ and D‐LDHs contributed to differences in the ratio of the two isomers and different types of Lactobacillus strains. In contrast to the situation in Lactobacillus strains, the ldh L transcription level in B. coagulans 2‐6 was much higher than that of ldh D in all growth phases, which might explain high optical purity of the l ‐lactate produced by this strain (Sun et al., ; Wang et al., ). Therefore, the crucial factors affecting the optical purity of lactate may differ among various LAB.…”

Section: Resultsmentioning

confidence: 85%

“…E. coli strains were grown in Luria‐Bertani (LB) medium on a rotary shaker at 37°C. Plasmid pMD18‐T was used for cloning the genes encoding LDHs, whereas plasmid pET‐28a was used to express the recombinant LDHs with a N‐terminal His‐tag (Sun et al., ; Zhou, Zhang, Meng, Zhang, & Li, ). All the reagents were of analytical grade and commercially available.…”

Section: Methodsmentioning

confidence: 99%

“…Quantitative real‐time PCR reactions were performed on a SteponePlus ™ real‐time PCR system (ABI) with SYBR Premix Ex Tag (TaKaRa, China) according to the manufacturer's instructions. The 2 −∆∆Ct relative quantification method was used to assess mRNA levels, with 16S rRNA as the internal reference gene (Sun et al., ; Wang et al., ; Zheng et al., ).…”

Section: Methodsmentioning

confidence: 99%

“…In this pathway, lactate dehydrogenases (LDHs) play key roles by catalyzing not only the transformation of pyruvate to lactate, but also the oxidation of nicotinamide adenine dinucleotide (NADH), which constitutes an important step in the metabolism and energy conversion of living cells (Andreevskaya et al., ; Wang, Ingram, & Shanmugam, ). Two optically pure isomers of lactate were produced from pyruvate as separate entities through reactions catalyzed by either the chiral‐specific d ‐lactate dehydrogenase (D‐LDH, EC 1.1.1.28) or l ‐lactate dehydrogenase (L‐LDH, EC 1.1.1.27) (Singhvi, Jadhav, & Gokhale, ; Sun, Zhang, Lyu, Wang, & Yu, ; Wang, Cai, Zhu, Guo, & Yu, ; Zheng et al., ; Zhu et al., ). A sequence comparison has shown that D‐LDH and L‐LDH belong to two distinct families, the NAD‐dependent L‐ and D‐2‐hydroxyacid dehydrogenases, respectively (Cristescu & Egbosima, ; Ma et al., ).…”

Section: Introductionmentioning

confidence: 99%

“…They found that L‐ and D‐LDHs coexisted in three Lactobacillus genomes, with the relative catalytic efficiencies of enzymes playing a crucial role for the optical purity of lactate in Lactobacillus strains (Zheng et al., ). Subsequently, a study with Bacillus coagulans 2–6, which contained both D‐LDH and L‐LDH, showed that elevated catalytic efficiency of L‐LDH toward pyruvate and high transcription ratio of ldh L to ldh D constituted the main factors for the high optical purity of l ‐lactate produced by this strain(Sun et al., ; Wang et al., ). These findings indicate that different L‐ and D‐LDH activity levels and ldh L and ldh D mRNA amounts in LAB contribute to differences in the ratio of the two isomers.…”

Section: Introductionmentioning

confidence: 99%

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Relative catalytic efficiencies and transcript levels of three d‐ and two l‐lactate dehydrogenases for optically pure d‐lactate production in Sporolactobacillus inulinus

Zheng

et al. 2018

MicrobiologyOpen

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As the optical purity of the lactate monomer is pivotal for polymerization, the production of optically pure d-lactate is of significant importance. Sporolactobacillus inulinus YBS1-5 is a superior optically pure d-lactate-producing bacterium. However, little is known about the relationship between lactate dehydrogenases in S. inulinus YBS1-5 and the optical purity of d-lactate. Three potential d-lactate dehydrogenase (D-LDH1-3)- and two putative l-lactate dehydrogenase (L-LDH1-2)-encoding genes were cloned from the YBS1-5 strain and expressed in Escherichia coli D-LDH1 exhibited the highest catalytic efficiency toward pyruvate, whereas two L-LDHs showed low catalytic efficiency. Different neutralizers significantly affected the optical purity of d-lactate produced by strain YBS1-5 as well as the transcription levels of ldhDs and ldhLs. The high catalytic efficiency of D-LDH1 and elevated ldhD1 mRNA levels suggest that this enzyme is essential for d-lactate synthesis in S. inulinus YBS1-5. The correlation between the optical purity of d-lactate and transcription levels of ldhL1 in the case of different neutralizers indicate that ldhL1 is a key factor affecting the optical purity of d-lactate in S. inulinus YBS1-5.

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Section: Resultsmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Relative catalytic efficiencies and transcript levels of three d‐ and two l‐lactate dehydrogenases for optically pure d‐lactate production in Sporolactobacillus inulinus

Zheng

et al. 2018

MicrobiologyOpen

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Study of Photocarriers Lifetime Distribution in a‐Si:H via Magneto‐photoconductivity and Magneto‐Photoluminescence

McLaughlin

Pan

Sun

et al. 2022

Advanced Optical Materials

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a detailed understanding of the dynamics of photogenerated charge carriers has remained incomplete due to the complexity of the microscopic landscape of amorphous systems. The band structure formalism that leads to accurate descriptions of well-ordered crystalline semiconductors fails to adequately describe the behavior of amorphous systems, which are characterized by an exponentially decaying density of states in energies that extend into the classically forbidden band gap (see Figure 1a). Due to this large density of native defects and mid-gap states such as dangling bonds (DBs, see Figure 1a), the dynamics of photogenerated carriers in a-Si:H resemble to those of organic semiconductors, where the charge transport may also occur by hopping between nearby localized states having similar carrier mobility values. Also radiative recombination occurs between localized, strongly exchange-coupled electron-hole (e-h) polaron pairs. In addition, the photogenerated carriers are similarly localized in both systems. For these reasons, there might be valuable insight to be gained by applying some of the models of spin-dependent recombination processes developed in the field of organic semiconductors [10][11][12] to the a-Si:H system, as done here.It is an experimentally challenging task to probe photocarriers in an energy-resolved manner so that the effects of wavefunction localization in such amorphous systems might be elucidated. Magnetic resonance experiments can be devised so that only a desired subset of the total photogenerated carrier population is probed. [13] For example, electrically detected magnetic resonance [14] is sensitive only to those carriers which participate in conduction, so that the g-factors and hyperfine coupling strengths of electrons or holes near their respective mobility edges may be revealed. Optically detected magnetic resonance [15][16][17] and light-induced electron spin resonance [18] are sensitive to localized spin ½ electrons or holes that are trapped in deep defect states and do not participate in transport. Powerful as these techniques are for probing the local environment of photogenerated charge carriers, it is desirable to supplement them by a careful investigation of the steady-state photoluminescence (PL) and photocurrent (PC) efficiency, so that practical a-Si:H devices operating in the steady-state regime may benefit from the thorough understanding of microscopic carriers dynamics.Herein, the magneto-photoluminescence (MPL) of localized photocarriers and magneto-photoconductivity (MPC) of delocalized photocarriers in amorphous hydrogenated silicon (a-Si:H) films and devices, respectively, are investigated. Both responses are caused by mixing of spin sublevels in the photogenerated electron-hole (e-h) pairs that alters their recombination and dissociation rates. The spin mixing occurs by a combination of hyperfine interaction (HFI) between spin ½ photocarriers and neighboring 29 Si and 1 H nuclei, and the Δg mechanism which originates from a difference in the Landé g-factors of el...

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Fast Adaptive Thermal Buffering by a Passive Open Shell Based on Transformation Thermodynamics

Liu

Sun

2018

Advcd Theory and Sims

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By using transformation thermodynamics, an open, adaptive thermal buffer shell (TBS) is designed and experimentally implemented with natural materials (layered copper and expanded polystyrene [EPS]). The TBS can store excessive heat flux quickly in the shell and release it slowly when it is needed, which also has some distinctive features: first it is a buffer shell that can avoid external extremes in temperature (either high or low) and also provide a relatively stable temperature for the interior of the shell when the temperature outside the shell has some fluctuations; second the TBS is not thermally insulated (with holes connected to the outside world) and the buffering effect of the TBS originates from the heat recycling mechanics, not thermal insulation; third the TBS has a short response time and the temperature inside the shell can be quickly adjusted according to the average temperature outside the shell; fourth the TBS is a passive device. Unlike traditional air conditioning, the TBS can work without an external power supply. The TBS will have many applications in energy recycling systems, smart heat controlling systems, and passive heat self-adaptation systems. Numerical simulations and experimental demonstrations are given to verify the function of the TBS.In the times of energy shortage, the recycling of heat energy becomes more and more important. Therefore, how to handle the heat dissipation, the heat storage, and thereby give an effective control of heat flux becomes an important subject. For some applications, it is desirable for heat to dissipate as quickly as possible, such as the heat generated on chips. For other applications, though, enough heat must be retained to resist cold. However, heat generated in the first case is usually wasted and seldom reused for the second case because these two situations occur

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Contributory roles of two l-lactate dehydrogenases for l-lactic acid production in thermotolerant Bacillus coagulans

Cited by 19 publications

References 29 publications

Relative catalytic efficiencies and transcript levels of three d‐ and two l‐lactate dehydrogenases for optically pure d‐lactate production in Sporolactobacillus inulinus

Relative catalytic efficiencies and transcript levels of three d‐ and two l‐lactate dehydrogenases for optically pure d‐lactate production in Sporolactobacillus inulinus

Study of Photocarriers Lifetime Distribution in a‐Si:H via Magneto‐photoconductivity and Magneto‐Photoluminescence

Fast Adaptive Thermal Buffering by a Passive Open Shell Based on Transformation Thermodynamics

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