Browsing by Author "Kumar, Deepak"

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    Biological production and recovery of 2,3-butanediol using arabinose from sugar beet pulp by Enterobacter ludwigii
    (Elsevier, 2022-04-21) Narisetty, Vivek; Narisetty, Sudheera; Jacob, Samuel; Kumar, Deepak; Leeke, Gary A.; Chandel, Anuj Kumar; Singh, Vijai; Srivastava, Vimal Chandra; Kumar, Vinod
    Sugar beet pulp (SBP) is a major byproduct from the sugar industries and consists of >20% w/w arabinose. The current work evaluated the potential of Enterobacter ludwigii assimilating pure arabinose and arabinose rich hydrolysate from SBP pellets for 2,3-butanediol (BDO) production. The hydrolysate was obtained through dilute acid pretreatment (DAP) with sulphuric acid. The process was optimized for acid and solid loading to obtain a hydrolysate free from furan derivatives. The effect of different levels of substrate (10–60 g/L) using pure arabinose was conducted in shake flask experiments, followed by co-fermentation with small amounts of glucose and SBP hydrolysate. After flask cultivations, BDO fermentations were carried-out in a bench-top bioreactor in batch and fed-batch modes using pure arabinose as well as SBP hydrolysate. The fed-batch culture led to BDO production of 42.9 and 35.5 g/L from pure arabinose and SBP hydrolysate with conversion yields of 0.31 and 0.29 g/g, respectively. Finally, BDO accumulated on pure arabinose and SBP hydrolysate were recovered using an aqueous two-phase extraction system. The recovery yield of BDO accumulated on arabinose and hydrolysate was ∼97%. The work demonstrated the feasibility of using SBP as a suitable feedstock for manufacturing BDO.
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    Fermentative valorisation of xylose-rich hemicellulosic hydrolysates from agricultural waste residues for lactic acid production under non-sterile conditions
    (Elsevier, 2023-05-18) Cox, Rylan; Narisetty, Vivek; Castro, Eulogio; Agrawal, Deepti; Jacob, Samuel; Kumar, Gopalakrishnan; Kumar, Deepak; Kumar, Vinod
    Lactic acid (LA) is a platform chemical with diverse industrial applications. Presently, commercial production of LA is dominated by microbial fermentation using sugary or starch-based feedstocks. Research pursuits emphasizing towards sustainable production of LA using non-edible and renewable feedstocks have accelerated the use of lignocellulosic biomass (LCB). The present study focuses on the valorisation of xylose derived from sugarcane bagasse (SCB) and olive pits (OP) through hydrothermal and dilute acid pretreatment, respectively. The xylose-rich hydrolysate obtained was used for LA production by homo-fermentative and thermophilic Bacillus coagulans DSM2314 strain under non-sterile conditions. The fed-batch mode of fermentation resulted in maximum LA titers of 97.8, 52.4 and 61.3 g/L with a yield of 0.77, 0.66 and 0.71 g/g using pure xylose, xylose-rich SCB and OP hydrolysates, respectively. Further, a two-step aqueous two-phase system (ATPS) extraction technique was employed for the separation and recovery of LA accumulated on pure and crude xylose. The LA recovery was 45 – 65% in the first step and enhanced to 80–90% in the second step.The study demonstrated an efficient integrated biorefinery approach to valorising the xylose-rich stream for cost-effective LA production and recovery.
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    Life cycle analysis of fermentative production of succinic acid from bread waste
    (Elsevier, 2021-04-23) Gadkari, Siddharth; Kumar, Deepak; Qin, Zi-hao; Lin, Carol Sze Ki; Kumar, Vinod
    According to the US Department of Energy, succinic acid (SA) is a top platform chemical that can be produced from biomass. Bread waste, which has high starch content, is the second most wasted food in the UK and can serve as a potential low cost feedstock for the production of SA. This work evaluates the environmental performance of a proposed biorefinery concept for SA production by fermentation of waste bread using a cradle-to-factory gate life cycle assessment approach. The performance was assessed in terms of greenhouse gas (GHG) emissions and non-renewable energy use (NREU). Waste bread fermentation demonstrated a better environmental profile compared to the fossil-based system, however, GHG emissions were about 50% higher as compared to processes using other biomass feedstocks such as corn wet mill or sorghum grains. NREU for fermentative SA production using waste bread was significantly lower than fossil-based system and about the same as that of established biomass-based processes, thus proving the great potential of waste bread as a valuable feedstock for bioproduction of useful chemicals. The results show that steam and heating oil used in the process were the biggest contributors to the NREU and GHG emissions. Sensitivity analyses highlighted the importance of the solid biomass waste generated in the process which can potentially be used as fish feed. The LCA analysis can be used for targeted optimization of SA production from bread waste, thereby enabling the utilization of an otherwise waste stream and leading to the establishment of a circular economy.
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    Myco-biorefinery approaches for food waste valorization: Present status and future prospects
    (Elsevier, 2022-07-09) Awasthi, Mukesh Kumar; Harirchi, Sharareh; Sar, Taner; VS, Vigneswaran; Rajendran, Karthik; Gómez-García, Ricardo; Hellwig, Coralie; Binod, Parameswaran; Sindhu, Raveendran; Madhavan, Aravind; Kumar, A.N. Anoop; Kumar, Vinod; Kumar, Deepak; Zhang, Zengqiang; Taherzadeh, Mohammad J.
    Increases in population and urbanization leads to generation of a large amount of food waste (FW) and its effective waste management is a major concern. But putrescible nature and high moisture content is a major limiting factor for cost effective FW valorization. Bioconversion of FW for the production of value added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting on production of multiple products will solve these issues to greater extent. This article provides an overview of bioconversion of FW to different value added products.
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    Organic waste recycling for carbon smart circular bioeconomy and sustainable development: a review
    (Elsevier, 2022-07-15) Awasthi, Mukesh Kumar; Yan, Binghua; Sar, Taner; Gómez-García, Ricardo; Ren, Liheng; Sharma, Pooja; Binod, Parameswaran; Sindhu, Raveendran; Kumar, Vinod; Kumar, Deepak; Mohamed, Badr A.; Zhang, Zengqiang; Taherzadeh, Mohammad J.
    The development of sustainable and low carbon impact processes for a suitable management of waste and by-products coming from different factors of the industrial value chain like agricultural, forestry and food processing industries. Implementing this will helps to avoid the negative environmental impact and global warming. The application of the circular bioeconomy (CB) and the circular economic models have been shown to be a great opportunity for facing the waste and by-products issues by bringing sustainable processing systems which allow to the value chains be more responsible and resilient. In addition, biorefinery approach coupled to CB context could offer different solution and insights to conquer the current challenges related to decrease the fossil fuel dependency as well as increase efficiency of resource recovery and processing cost of the industrial residues. It is worth to remark the important role that the biotechnological processes such as fermentative, digestive and enzymatic conversions play for an effective waste management and carbon neutrality.
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    Progress in microalgal mediated bioremediation systems for the removal of antibiotics and pharmaceuticals from wastewater
    (Elsevier, 2022-02-16) Chandel, Neha; Ahuja, Vishal; Gurav, Ranjit; Kumar, Vinod; Tyagi, Vinay Kumar; Pugazhendhi, Arivalagan; Kumar, Gopalakrishnan; Kumar, Deepak; Yang, Yung-Hun; Bhatia, Shashi Kant
    Worldwide demand for antibiotics and pharmaceutical products is continuously increasing for the control of disease and improvement of human health. Poor management and partial metabolism of these compounds result in the pollution of aquatic systems, leading to hazardous effects on flora, fauna, and ecosystems. In the past decade, the importance of microalgae in micropollutant removal has been widely reported. Microalgal systems are advantageous as their cultivation does not require additional nutrients: they can recover resources from wastewater and degrade antibiotics and pharmaceutical pollutants simultaneously. Bioadsorption, degradation, and accumulation are the main mechanisms involved in pollutant removal by microalgae. Integration of microalgae-mediated pollutant removal with other technologies, such as biodiesel, biochemical, and bioelectricity production, can make this technology more economical and efficient. This article summarizes the current scenario of antibiotic and pharmaceutical removal from wastewater using microalgae-mediated technologies.
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    Towards an improved understanding of plasticity, friction and wear mechanisms in precipitate containing AZ91 Mg alloy
    (Elsevier, 2020-02-28) Kumar, Deepak; Goel, Saurav; Gosvami, Nitya Nand; Jain, Jayant
    This work reports a combined experimental and atomistic simulation study on continuous precipitates (CPs) and discontinuous precipitates (DPs) affecting the scratch induced wear in AZ91 magnesium alloy. Nanoscratching experiments complemented by atomic simulations were performed to understand the directional dependence and origins of plasticity, friction and wear mechanisms as benchmarked to nanocrystalline HCP magnesium. Post scratch deformation analysis was performed using electron back scattering diffraction, scanning electron microscope and molecular dynamics (MD) simulation. The direction of orientation of the precipitates was observed to make a significant influence on the deformation behaviour. For example, regardless of the precipitates type (CP or DP), a ductile-brittle transition becomes pronounced while scratching along the direction (orientation) of precipitates, whilst a fully ductile response was obtained while scratching along the direction normal to the precipitates. However, regardless of the direction of orientation, DPs showed a higher wear resistance and coefficient of friction compared to the CPs. These observations were supported by the quantitative analysis of the planar defects such as coherent twins, extrinsic and intrinsic stacking faults in the deformation zone as well as 1/3〈11¯00〉" role="presentation"> ( and 1/3〈12¯10〉" role="presentation"> dislocations type extracted from the MD analysis.These observations will facilitate an improved design of AZ91 alloys in particular and intermetallic precipitate containing alloys in general.