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Mamata SINGHVI,Anoth MAHARJAN,Beom Soo KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
In this study, starch-based potato peel waste biomass (PWB) was used for hydrogen production through dark fermentation by the thermophillic amylase producing strain Parageobacillus thermoglucosidasius KCTC 33548. The effect of magnetic Fe₃O₄ nanoparticles (NPs) on hydrogen production from pure starch and starch-based PWB was experimentally studied and confirmed by kinetic analysis. The supplementation of optimized concentrations of both Fe₃O₄ NPs (300 ㎎/L) and L-cysteine (250 ㎎/L) during hydrogen fermentation using pure starch and PWB generated maximum cumulative hydrogen yields of 167 and 71.9 mL with maximum production rates of 2.81 and 1.26 mL/h, respectively. Further, the correlation between Fe₃O₄ and the expression of hydrogenase isoforms and the related hydrogenase activity was explored. Higher hydrogenase activity was obtained in the membrane-associated fractions (3.67 U/㎎ of protein) of cells grown in the presence of Fe₃O₄. Zymogram analysis exhibited two additional isoforms (Hyd 1 and Hyd 2) in fermented broth containing Fe₃O₄ NPs indicating the role of Fe ions in expression of hydrogenase isoforms.
정지완,SINGHVI MAMATA SACHIN,김범수 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.3
In this study, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was produced using extracellular enzymes present in the supernatant of Pseudomonas aeruginosa. DOD concentration and productivity were improved using extracellular enzymes obtained from P. aeruginosa culture broth than using conventional whole cell culture method. Among the different carbon sources used during cell preculture, glycerol showed higher DOD production than using glucose or crude glycerol. In batch process, the highest concentration of DOD (8.82 g/L) was accomplished using supernatant derived from 12 h-grown pre-culture of P. aeruginosa strain after 72 h of bioconversion process. To further improve DOD production, a fed-batch process was used with the addition of surfactant and enzyme concentrate. The fed-batch process using a 4-fold concentrated enzyme solution with Tween 80 yielded the highest DOD concentration (27.5 g/L at 72 h) with an 8.28-fold increase in DOD production compared to using whole cells. The prominence of this study was that the highest DOD production (27.5 g/L) ever reported was achieved using extracellular enzymes via a fed-batch process. Another significant aspect of this study is the possibility of utilizing abundantly available crude glycerol substrate for DOD production, which will help direct the development of sustainable process. Therefore, the overall study is projected to speed up the development of DOD production using inexpensive substrates such as crude glycerol on a larger scale.
Biosynthesis of Nicotinamide Mononucleotide through Metabolic Engineering of Escherichia coli
Anoth MAHARJAN,Mamata SINGHVI,Beom soo KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Biosynthesis of nicotinamide mononucleotide (NMN) is attained by direct conversion of nicotinamide (NAM) with the help of nicotinamide phosphoribosyltransferase (NAMPT) gene via salvage pathway. NMN is intermediate product generated during NAD⁺ biosynthesis. It has long-term pharmacological activities and hence recently it has gained much attention in preclinical studies. The current study has focused on the metabolic engineering of NAMPT, phosphoribosyl pyrophosphate synthetase 1 (PRPS1) and PRPS2 (from Homo sapiens) genes in E. coli. to investigate the effect of PRPS1 and PRPS2 on NMN biosynthesis. Batch fermentation studies exhibited 1.08 mM NMN in the presence of ㎎<SUP>2+</SUP> and phosphates through whole cell biocatalysis with IPTG induction. Further, using response surface methodology (RSM), 1.8 mM of NMN was obtained when supplemented with 1% ribose, 1 mM ㎎<SUP>2+</SUP> and phosphate, and 0.5% NAM. Process optimization can be further implied for economical production of NMN using recombinant strain of E. coli BL21 (DE3), which is the future perspective of the current study.
Optical dating of late Quaternary carbonate sequences of Saurashtra, western India
Sharma, Komal,Bhatt, Nilesh,Shukla, Anil Dutt,Cheong, Dae-Kyo,Singhvi, Ashok Kumar Cambridge University Press 2017 Quaternary research Vol.87 No.1
<B>Abstract</B><P>Bioclastic carbonate deposits that formed because of a combination of nearshore marine, fluvial, and aeolian processes, occur along the Saurashtra coast and in the adjacent interior regions of western India. Whether these carbonates formed by marine or aeolian processes has been debated for many decades. The presence of these deposits inland poses questions as to whether they are climate controlled or attributable to postdepositional tectonic uplift. In particular, the debate centres on chronologic issues including (1) appropriate sampling strategies and (2) the use of <SUP>230</SUP>Th/<SUP>234</SUP>U and <SUP>14</SUP>C ages on the bulk carbonates. Using traces (<1%) of quartz grains trapped in carbonate matrices, optically stimulated luminescence (OSL) dating of quartz grains, deposited along with the carbonate grains, provides ages for the most recent deposition events. The OSL ages range from >165 to 44 ka for the shell limestones, 75-17 ka for the fluvially reworked sheet deposits, and 80-11 ka for miliolites deposited by aeolian processes. These are younger than the <SUP>230</SUP>Th/<SUP>234</SUP>U and <SUP>14</SUP>C ages and suggest that the inland carbonate deposits were reworked from older carbonate sediments that were transported during more arid phases.</P>
Pisa Syndrome in Subacute Sclerosing Panencephalitis: A Case Report and Review of the Literature
Sandeep Kaur,Amit Shankar Singh,Sudesh Prabhakar,Jeenendra Prakash Singhvi,Harpreet Singh Mann,Arun Kaul 대한파킨슨병및이상운동질환학회 2023 Journal Of Movement Disorders Vol.16 No.3
Subacute sclerosing panencephalitis (SSPE) is a slowly progressive central nervous system disorder affecting children and young individuals and is caused by mutant measles virus persistence. Patients with SSPE may present with extrapyramidal manifestations such as tics, dystonia, parkinsonism, and chorea