Browsing by Author "Pandey, Ashok"

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    Cleaner technologies to combat heavy metal toxicity
    (Elsevier, 2021-07-10) Rebello, Sharrel; Sivaprasad, M. S.; Anoopkumar, A. N.; Jayakrishnan, Lekshmi; Aneesh, Embalil Mathachan; Narisetty, Vivek; Sindhu, Raveendran; Binod, Parameswaran; Pugazhendhi, Arivalagan; Pandey, Ashok
    Heavy metals frequently occur as silent poisons present in our daily diet, the environment we live and the products we use, leaving us victims to various associated drastic health and ecological bad effects even in meagre quantities. The prevalence of heavy metals can be traced from children's toys, electronic goods, industrial effluents, pesticide preparation, and even in drinking water in some instances; necessitating methods to remediate them. The current review discusses the various physicochemical and biological methods employed to tackle the problem of heavy metal pollution. Apart from the conventional methods following the principles of adsorption, precipitation, coagulation, and various separation techniques, the advancements made in the directions of biological heavy metal detoxification using microbes, plants, algae have been critically analyzed to identify the specific utility of different agents for specific heavy metal removal. The review paper is a nutshell of different heavy metal remediation strategies, their merits, demerits, and modifications done to alleviate process of heavy metal pollution.
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    Current state of the art biotechnological strategies for conversion of watermelon wastes residues to biopolymers production: a review
    (Elsevier, 2021-12-14) Awasthi, Mukesh Kumar; Kumar, Vinay; Yadav, Vivek; Sarsaiya, Surendra; Awasthi, Sanjeev Kumar; Sindhu, Raveendran; Binod, Parameswaran; Kumar, Vinod; Pandey, Ashok; Zhang, Zengqiang
    Poly-3-hydroxyalkanoates (PHA) are biodegradable and compostable polyesters. This review is aimed to provide a unique approach that can help think tanks to frame strategies aiming for clean technology by utilizing cutting edge biotechnological advances to convert fruit and vegetable waste to biopolymer. A PHA manufacturing method based on watermelon waste residue that does not require extensive pretreatment provides a more environmentally friendly and sustainable approach that utilizes an agricultural waste stream. Incorporating fruit processing industry by-products and water, and other resource conservation methods would not only make the manufacturing of microbial bio-plastics like PHA more eco-friendly, but will also help our sector transition to a bioeconomy with circular product streams. The final and most critical element of this review is an in-depth examination of the several hazards inherent in PHA manufacturing.
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    Development of hypertolerant strain of Yarrowia lipolytica accumulating succinic acid using high levels of acetate
    (American Chemical Society, 2022-08-09) Narisetty, Vivek; Prabhu, Ashish A.; Bommareddy, Rajesh Reddy; Cox, Rylan; Agrawal, Deepti; Misra, Ashish; Ali Haider, M.; Bhatnagar, Amit; Pandey, Ashok; Kumar, Vinod
    Acetate is emerging as a promising feedstock for biorefineries as it can serve as an alternate carbon source for microbial cell factories. In this study, we expressed acetyl-CoA synthase in Yarrowia lipolytica PSA02004PP, and the recombinant strain grew on acetate as the sole carbon source and accumulated succinic acid or succinate (SA). Unlike traditional feedstocks, acetate is a toxic substrate for microorganisms; therefore, the recombinant strain was further subjected to adaptive laboratory evolution to alleviate toxicity and improve tolerance against acetate. At high acetate concentrations, the adapted strain Y. lipolytica ACS 5.0 grew rapidly and accumulated lipids and SA. Bioreactor cultivation of ACS 5.0 with 22.5 g/L acetate in a batch mode resulted in a maximum cell OD600 of 9.2, with lipid and SA accumulation being 0.84 and 5.1 g/L, respectively. However, its fed-batch cultivation yielded a cell OD600 of 23.5, SA titer of 6.5 g/L, and lipid production of 1.5 g/L with an acetate uptake rate of 0.2 g/L h, about 2.86 times higher than the parent strain. Cofermentation of acetate and glucose significantly enhanced the SA titer and lipid accumulation to 12.2 and 1.8 g/L, respectively, with marginal increment in cell growth (OD600: 26.7). Furthermore, metabolic flux analysis has drawn insights into utilizing acetate for the production of metabolites that are downstream to acetyl-CoA. To the best of our knowledge, this is the first report on SA production from acetate by Y. lipolytica and demonstrates a path for direct valorization of sugar-rich biomass hydrolysates with elevated acetate levels to SA.
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    High yield recovery of 2,3-butanediol from fermented broth accumulated on xylose rich sugarcane bagasse hydrolysate using aqueous two-phase extraction system
    (Elsevier, 2021-06-26) Narisetty, Vivek; Amraoui, Yassin; Abdullah, Alamri; Ahmad, Ejaz; Agrawal, Deepti; Parameswaran, Binod; Pandey, Ashok; Goel, Saurav; Kumar, Vinod
    Downstream processing of chemicals obtained from fermentative route is challenging and cost-determining factor of any bioprocess. 2,3-Butanediol (BDO) is a promising chemical building block with myriad applications in the polymer, food, pharmaceuticals, and fuel sector. The current study focuses on the recovery and purification of BDO produced (68.2 g/L) from detoxified xylose-rich sugarcane bagasse hydrolysate by a mutant strain of Enterobacter ludwigii. Studies involving screening and optimization of aqueous-two phase system (ATPS) revealed that 30% w/v (NH4)2SO4 addition to clarified fermentation broth facilitated BDO extraction in isopropanol (0.5 v/v), with maximum recovery and partition coefficient being 97.9 ± 4.6% and 45.5 ± 3.5, respectively. The optimized protocol was repeated with unfiltered broth containing 68.2 g/L BDO, cell biomass, and unspent protein, which led to the partitioning of 66.7 g/l BDO, 2.0 g/L xylose and 9.0 g/L acetic acid into organic phase with similar BDO recovery (97%) and partition coefficient (45).
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    Isobutanol production by Candida glabrata – A potential organism for future fuel demands
    (Elsevier, 2021-08-13) Lakshmi, Nair M.; Binoop, Mohan; Salini, Chandrasekharan Nair; Vivek, Narisetty; Sindhu, Raveendran; Pandey, Ashok; Binod, Parameswaran
    Due to global concern on the sustainability of energy from fossil fuels, isobutanol as a biofuel has urged attention in recent years due to its high octane number, higher blending capacity, low vapour pressure and higher energy content. The present study reports a novel wild strain, Candida glabrata, which produces isobutanol under submerged fermentation condition. Different process parameters have been optimized by both conventional as well as statistical methods. The production of isobutanol is enhanced in the presence of valine and this attribute the degradation pathway of valine is highly depend on isobutanol production. Under optimized condition, the yield of isobutanol is increased from 0.19 g/L to 0.96 g/L. This strain has not yet reported for the production of isobutanol.
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    Process optimization for recycling of bread waste into bioethanol and biomethane: a circular economy approach
    (Elsevier, 2022-05-28) Narisetty, Vivek; Nagarajan, Sanjay; Gadkari, Siddharth; Ranade, Vivek V.; Zhang, Jingxin; Patchigolla, Kumar; Bhatnagar, Amit; Awasthi, Mukesh Kumar; Pandey, Ashok; Kumar, Vinod
    Bread is the second most wasted food in the UK with annual wastage of 292,000 tons. In the present work, bread waste (BW) was utilized for fermentative production of ethanol by Saccharomyces cerevisiae KL17. Acidic and enzymatic saccharification of BW was carried out resulting in the highest glucose release of 75 and 97.9 g/L which is 73.5 and 95.9% of theoretical yield, respectively. The obtained sugars were fermented into ethanol initially in shake flask followed by scale up in bioreactor in batch and fed-batch mode. In the fed-batch mode of cultivation, the maximum ethanol titers of 111.3, 106.9, and 114.9 g/L with conversion yield and productivity of 0.48, 0.47, and 0.49 g/g, and 3.1, 3.0, and 3.2 g/L.h was achieved from pure glucose, glucose-rich acidic and enzymatic hydrolysates, respectively. Further to improve the process economics, the solid residues after acidic (ABW) and enzymatic (EBW) hydrolysis of BW along with respective fermentation residues (FR) obtained after the ethanol production were pooled and subjected to anaerobic digestion. The solid residue from ABW + FR, and EBW + FR yielded a biochemical methanation potential (BMP) of 345 and 379 mL CH4/g VS, respectively. Life cycle assessment of the process showed that the total emissions for ethanol production from BW were comparable to the emissions from more established feedstocks such as sugarcane and maize grain and much lower when compared to wheat and sweet potato. The current work demonstrates BW as promising feedstock for sustainable biofuel production with the aid of circular biorefining strategy. To the authors knowledge, this is the first time, such a sequential system has been investigated with BW for ethanol and biomethane production. Further work will be aimed at ethanol production at pilot scale and BMP will be accessed in a commercial anaerobic digester.
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    Recent advances in biodiesel production: challenges and solutions
    (Elsevier, 2021-06-28) Mathew, Gincy Marina; Raina, Diksha; Narisetty, Vivek; Kumar, Vinod; Saran, Saurabh; Pugazhendi, Arivalagan; Sindhu, Raveendran; Pandey, Ashok; Binod, Parameswaran
    Mono alkyl fatty acid ester or methyl ethyl esters (biodiesel) are the promising alternative for fossil fuel or petroleum derived diesel with similar properties and could reduce the carbon foot print and the greenhouse gas emissions. Biodiesel can be produced from renewable and sustainable feedstocks like plant derived oils, and it is biodegradable and non-toxic to the ecosystem. The process for the biodiesel production is either through traditional chemical catalysts (Acid or Alkali Transesterification) or enzyme mediated transesterification, but as enzymes are natural catalysts with environmentally friendly working conditions, the process with enzymes are proposed to overcome the drawbacks of chemical synthesis. At present 95% of the biodiesel production is contributed by edible oils worldwide whereas recycled oils and animal fats contribute 10% and 6% respectively. Although every process has its own limitations, the enzyme efficiency, resistance to alcohols, and recovery rate are the crucial factors to be addressed. Without any benefit of doubt, production of biodiesel using renewable feedstocks and enzymes as the catalysts could be recommended for the commercial purpose, but further research on improving the efficiency could be an advantage.
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    Recent advances in microbial biosynthesis of C3 – C5 diols: Genetics and process engineering approaches
    (Elsevier, 2020-12-13) Vivek, Narisetty; Hazeen, Sulfath Hakkim; Alphy, Maria Paul; Kumar, Vinod; Magdouli, Sara; Sindhu, Raveendran; Pandey, Ashok; Binod, Parameswaran
    Diols derived from renewable feedstocks have significant commercial interest in polymer, pharmaceutical, cosmetics, flavors and fragrances, food and feed industries. In C3-C5 diols biological processes of 1,3-propanediol, 1,2-propanediol and 2,3-butanediol have been commercialized as other isomers are non-natural metabolites and lack natural biosynthetic pathways. However, the developments in the field of systems and synthetic biology paved a new path to learn, build, construct, and test for efficient chassis strains. The current review addresses the recent advancements in metabolic engineering, construction of novel pathways, process developments aimed at enhancing in production of C3-C5 diols. The requisites on developing an efficient and sustainable commercial bioprocess for C3-C5 diols were also discussed
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    Retrieving back plastic wastes for conversion to value added petrochemicals: opportunities, challenges and outlooks
    (Elsevier, 2023-06-01) Kumar, Manish; Bolan, Shiv; Padhye, Lokesh P.; Konarova, Muxina; Foong, Shin Ying; Lam, Su Shiung; Wagland, Stuart T.; Cao, Runzi; Li, Yang; Batalha, Nuno; Ahmed, Mohamed; Pandey, Ashok; Siddique, Kadambot H.M.; Wang, Hailong; Rinklebe, Jörg; Bolan, Nanthi
    Plastic production and its unplanned management and disposal, has been shown to pollute terrestrial, aquatic, and atmospheric environments. Petroleum-derived plastics do not decompose and tend to persist in the surrounding environment for longer time. Plastics can be ingested and accumulate into the tissues of both terrestrial and aquatic animals, which can impede their growth and development. Petrochemicals are the primary feedstocks for the manufacture of plastics. The plastic wastes can be retrieved back for conversion to value added petrochemicals including aromatic char, hydrogen, synthesis gas, and bio-crude oil using various technologies including thermochemical, catalytic conversion and chemolysis. This review focusses on technologies, opportunities, challenges and outlooks of retrieving back plastic wastes for conversion to value added petrochemicals. The review also explores both the technical and management approaches for conversion of plastic wastes to petrochemicals in regard to commercial feasibility, and economic and environmental sustainability. Further, this review work provides a detailed discussion on opportunities and challenges associated with recent thermochemical and catalytic conversion technologies adopted for retrieving plastic waste to fuels and chemicals. The review also recommends prospects for future research to improve the processes and cost-efficiency of promising technologies for conversion of plastic wastes to petrochemicals. It is envisioned that this review would overcomes the knowledge gaps on conversion technologies and further contribute in emerging sustainable approaches for exploiting plastic wastes for value-added products.
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    Sweet sorghum juice as an alternative carbon source and adaptive evolution of Lactobacillus brevis NIE9.3.3 in sweet sorghum juice and biodiesel derived crude glycerol to improve 1, 3 propanediol production
    (Elsevier, 2021-07-21) Alphy, Maria Paul; Anjali, Kodakkattil Babu; Vivek, Narisetty; Thirumalesh, Banjagere Veerabhadrappa; Sindhu, Raveendran; Pugazhendi, Arivalagan; Pandey, Ashok; Binod, Parameswaran
    Sweet sorghum juice (SSJ) is considered as an ideal complement for carbon supplement in ethanol fermentation for its ease of cultivation. Extraction of fermentable sugars from the sweet sorghum is very simple in comparison to lignocellulosic biomass. Hence sweet sorghum is a suitable candidate as a feedstock. In the present study, batch fermentations were carried out using Lactobacillus brevis NIE9.3.3, a facultative anaerobe, isolated through onsite enrichment technique to produce 1,3-propanediol and other co-metabolites, in glucose-glycerol co-fermentation. To make the process more sustainable, the glucose supplemented in the production media was replaced with SSJ. The supplementation of 40 g/L sorghum juice and 40 g/L crude glycerol in the production media resulted in the titre of 25.9 g/L 1, 3-PDO with a volumetric yield of 0.64 g 1,3-PDO/g glycerol. Adaptation of the microorganisms and cultivation under controlled conditions of temperature and substrate concentrations followed by selection was carried out, that is, adaptive evolution. Among the adaptively evolved strains, PD 20.100 has displayed better performance and increased the titres up to 38.4 g/L with a volumetric yield of 0.64 g 1,3-PDO/g glycerol. The industrial applicability of the fermentation process was checked in pilot scale and the production yield was comparable with that of flask scale. The utilization of agricultural and biodiesel industrial waste for the production of 1,3-PDO by a non-pathogenic organism and the strain improvement through ALE for better utilization and conversion of substrates indicates the novelty of this work.
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    Upgrading the value of anaerobic fermentation via renewable chemicals production: A sustainable integration for circular bioeconomy
    (Elsevier, 2021-09-14) Kumar, A. Naresh; Sarkar, Omprakash; Chandrasekhar, K.; Raj, Tirath; Narisetty, Vivek; Mohan, S. Venkata; Pandey, Ashok; Varjani, Sunita; Kumar, Sunil; Sharma, Pooja; Jeon, Byong-Hun; Jang, Min; Kim, Sang-Hyoun
    The single bioprocess approach has certain limitations in terms of process efficiency, product synthesis, and effective resource utilization. Integrated or combined bioprocessing maximizes resource recovery and creates a novel platform to establish sustainable biorefineries. Anaerobic fermentation (AF) is a well-established process for the transformation of organic waste into biogas; conversely, biogas CO2 separation is a challenging and cost-effective process. Biological fixation of CO2 for succinic acid (SA) mitigates CO2 separation issues and produces commercially important renewable chemicals. Additionally, utilizing digestate rich in volatile fatty acid (VFA) to produce medium-chain fatty acids (MCFAs) creates a novel integrated platform by utilizing residual organic metabolites. The present review encapsulates the advantages and limitations of AF along with biogas CO2 fixation for SA and digestate rich in VFA utilization for MCFA in a closed-loop approach. Biomethane and biohydrogen process CO2 utilization for SA production is cohesively deliberated along with the role of biohydrogen as an alternative reducing agent to augment SA yields. Similarly, MCFA production using VFA as a substrate and function of electron donors namely ethanol, lactate, and hydrogen are comprehensively discussed. A road map to establish the fermentative biorefinery approach in the framework of AF integrated sustainable bioprocess development is deliberated along with limitations and factors influencing for techno-economic analysis. The discussed integrated approach significantly contributes to promote the circular bioeconomy by establishing carbon-neutral processes in accord with sustainable development goals.