Browsing by Author "Budakoti, Mridul"

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    Strategies and tools for the biotechnological valorization of glycerol to 1, 3-propanediol: challenges, recent advancements and future outlook
    (Elsevier, 2023-05-22) Agrawal, Deepti; Budakoti, Mridul; Kumar, Vinod
    Global efforts towards decarbonization, environmental sustainability, and a growing impetus for exploiting renewable resources such as biomass have spurred the growth and usage of bio-based chemicals and fuels. In light of such developments, the biodiesel industry will likely flourish, as the transport sector is taking several initiatives to attain carbon-neutral mobility. However, this industry would inevitably generate glycerol as an abundant waste by-product. Despite being a renewable organic carbon source and assimilated by several prokaryotes, presently realizing glycerol-based biorefinery is a distant reality. Among several platform chemicals such as ethanol, lactic acid, succinic acid, 2, 3-butanediol etc., 1, 3-propanediol (1, 3-PDO) is the only chemical naturally produced by fermentation, with glycerol as a native substrate. The recent commercialization of glycerol-based 1, 3-PDO by Metabolic Explorer, France, has revived research interests in developing alternate cost-competitive, scalable and marketable bioprocesses. The current review outlines natural glycerol assimilating and 1, 3-PDO-producing microbes, their metabolic pathways, and associated genes. Later, technical barriers are carefully examined, such as the direct use of industrial glycerol as input material and genetic and metabolic issues related to microbes alleviating their industrial use. Biotechnological interventions exploited in the past five years, which can substantially circumvent these challenges, such as microbial bioprospecting, mutagenesis, metabolic, evolutionary and bioprocess engineering, including their combinations, are discussed in detail. The concluding section sheds light on some of the emerging and most promising breakthroughs which have resulted in evolving new, efficient, and robust microbial cell factories and/or bioprocesses for glycerol-based 1, 3-PDO production.
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    Unveiling the potential of a novel alkalophilic Citrobacter freundii IIPDR3 strain in valorizing glycerol to 1,3-propanediol
    (Springer, 2024-12-31) Budakoti, Mridul; Bhandari, Shivani; Agrawal, Deepti; Kumar, Vinod
    Glycerol-based biotechnological production of 1,3-propanediol (PDO) has taken center stage after its recent commercialization by Metabolic Explorer. The present study unveils the potential of a novel alkalophilic, BSL-1 bacterium Citrobacter freundii IIPDR3 to produce 1,3-PDO from glycerol. The culture conditions were optimized at shake flask level using one-variable-at-a-time (OVAT) approach, and statistically significant parameters were identified. The optimal conditions for batch production of 1,3-PDO were phosphate-buffered glycerol-based medium essentially containing 1.5 gL−1 ammonium sulfate, 3 gL−1 yeast extract, and 0.5 gL−1 magnesium sulphate, temperature 36 °C, pH–stat of 8.0, and inoculum size being ≥ 35 µgbacterial cells/mL on dry cell weight (DCW) basis. Incorporation of 0.2% Tween 80 in the fermentation medium improved glycerol uptake rate and prevented self-flocculation of bacterial cells. Using liquor NH3 as a neutralizing agent, C. freundii IIPDR3 produced a maximum of 18.04 ± 0.76 gL−1 1,3-PDO from pure glycerol, with productivity and yield being 1.72 gL−1 h−1 and 0.53 gg−1, respectively. When the robustness of the strain was tested on crude glycerol (CG), it accumulated 9.65 and 11.11gL−1 1,3-PDO in 7 h and 10.5 h with initial glycerol concentrations of 20 and 40 gL−1, respectively. The study confirms that C. freundii IIPDR3 can be a promising candidate to tackle CG, a prominent waste derived from biodiesel industry, and simultaneously upgrade it to valorized products such as 1,3-PDO.