Browsing by Author "Kumar, Gopalakrishnan"
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Item Open Access Bread waste – a potential feedstock for sustainable circular biorefineries(Elsevier, 2022-12-21) Kumar, Vinod; Brancoli, Pedro; Narisetty, Vivek; Wallace, Stephen; Charalampopoulos, Dimitris; Kumar Dubey, Brajesh; Kumar, Gopalakrishnan; Bhatnagar, Amit; Bhatia, Shashi Kant; Taherzadeh, Mohammad J.The management of staggering volume of food waste generated (∼1.3 billion tons) is a serious challenge. The readily available untapped food waste can be promising feedstock for setting up biorefineries and one good example is bread waste (BW). The current review emphasis on capability of BW as feedstock for sustainable production of platform and commercially important chemicals. It describes the availability of BW (>100 million tons) to serve as a feedstock for sustainable biorefineries followed by examples of platform chemicals which have been produced using BW including ethanol, lactic acid, succinic acid and 2,3-butanediol through biological route. The BW-based production of these metabolites is compared against 1G and 2G (lignocellulosic biomass) feedstocks. The review also discusses logistic and supply chain challenges associated with use of BW as feedstock. Towards the end, it is concluded with a discussion on life cycle analysis of BW-based production and comparison with other feedstocks.Item Open Access Comprehensive techno-economic and environmental assessment for 2,3-butanediol production from bread waste(Elsevier, 2024-11-15) Tiwari, Bikash R.; Maity, Sunil K.; Brar, Satinder K.; Chew, Kit Wayne; Kumar, Gopalakrishnan; Kumar, VinodBread waste (BW) is a common food waste in Europe and North America and has enormous potential as a biorefinery substrate for the sustainable synthesis of various platform chemicals. Our previous work made use of BW for the fermentative production of 2,3–butanediol (BDO). The present work evaluated the economic prospects and environmental consequences associated with the overall processes, handling 100 metric tons BW per day. The comprehensive process design using Aspen Plus and integrated techno-economic and environmental assessment was carried out for two different BW hydrolysis scenarios: acid and enzyme hydrolysis, followed by fermentation and extraction-based downstream BDO separation. The optimal heat exchanger network was designed using pinch analysis, which improved the energy efficiency of the processes significantly, with about 10 % savings of BDO production costs. Despite this improvement, the BDO derived from BW was exorbitant (4.2–6.9 $/kg) compared to the market price (3.23 $/kg) due to relatively higher capital investment for the current plant capacity. Further, the process inventory was modelled in SimaPro v9.1.0 to estimate the environmental consequences of these production processes for various impact categories, such as global warming (2.63 – 3.19 kg CO2 eq.), marine eutrophication (3.55 × 10-4 – 4.01 × 10-4 kg N eq.), terrestrial ecotoxicity (6.44 – 7.88 kg 1,4 − DCB), etc. Sensitivity and uncertainty analyses were also conducted to establish the reliability of the results. It was found that the enzyme hydrolysis was associated with lower environmental impacts than acid hydrolysis. This comprehensive study can be used as a guideline for developing sustainable BW-based biorefinery in the future.Item Open Access Enhanced biohydrogen generation through calcium peroxide engendered efficient ultrasonic disintegration of waste activated sludge in low temperature environment(Elsevier, 2022-10-27) Banu, J. Rajesh; Preethi; Gunasekaran, M.; Kumar, Vinod; Bhatia, Shashi Kant; Kumar, GopalakrishnanWaste activated sludge is a renewable source for biohydrogen production, whereas the presence of complex biopolymers limits the hydrolysis step during this process, and thus pretreatment is required to disintegrate the sludge biomass. In this study, the feasibility of utilizing waste activated sludge to produce biohydrogen by improving the solubilization by means of thermo CaO2 engendered sonication disintegration (TCP-US) was studied. The optimized condition for extracellular polymeric substance (EPS) dissociation was obtained at the CaO2 dosage of 0.05 g/g SS at 70 °C. The maximum disintegration after EPS removal was achieved at the sonic specific energy input of 1612.8 kJ/kg TS with the maximum solubilization and SS reduction of 23.7% and 18.14%, respectively, which was higher than the US alone pretreatment. Thus, this solubilization yields higher biohydrogen production of 114.3 mLH2/gCOD in TCP-US sample.Item Open Access 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, VinodLactic 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.Item Open Access Integrated biorefineries for repurposing of food wastes into value-added products(Elsevier, 2022-09-01) Narisetty, Vivek; Adlakha, Nidhi; Singh, Navodit Kumar; Dalei, Sudipt Kumar; Prabhu, Ashish A.; Nagarajan, Sanjay; Kumar, A. Naresh; Nagoth, Joseph Amruthraj; Kumar, Gopalakrishnan; Singh, Vijai; Kumar, VinodFood waste (FW) generated through various scenarios from farm to fork causes serious environmental problems when either incinerated or disposed inappropriately. The presence of significant amounts of carbohydrates, proteins, and lipids enable FW to serve as sustainable and renewable feedstock for the biorefineries. Implementation of multiple substrates and product biorefinery as a platform could pursue an immense potential of reducing costs for bio-based process and improving its commercial viability. The review focuses on conversion of surplus FW into range of value-added products including biosurfactants, biopolymers, diols, and bioenergy. The review includes in-depth description of various types of FW, their chemical and nutrient compositions, current valorization techniques and regulations. Further, it describes limitations of FW as feedstock for biorefineries. In the end, review discuss future scope to provide a clear path for sustainable and net-zero carbon biorefineries.Item Open Access Life cycle assessment of microbial 2,3-butanediol production from brewer’s spent grain modeled on pinch technology(American Chemical Society, 2023-05-22) Tiwari, Bikash Ranjan; Bhar, Rajarshi; Dubey, Brajesh Kumar; Maity, Sunil K.; Brar, Satinder Kaur; Kumar, Gopalakrishnan; Kumar, VinodMicrobial production of 2,3-butanediol (BDO) has received considerable attention as a promising alternate to fossil-derived BDO. In our previous work, BDO concentration >100 g/L was accumulated using brewer’s spent grain (BSG) via microbial routes which was followed by techno-economic analysis of the bioprocess. In the present work, a life cycle assessment (LCA) was conducted for BDO production from the fermentation of BSG to identify the associated environmental impacts. The LCA was based on an industrial-scale biorefinery processing of 100 metric tons BSG per day modeled using ASPEN plus integrated with pinch technology, a tool for achieving maximum thermal efficiency and heat recovery from the process. For the cradle-to-gate LCA, the functional unit of 1 kg of BDO production was selected. One-hundred-year global warming potential of 7.25 kg CO2/kg BDO was estimated while including biogenic carbon emission. The pretreatment stage followed by the cultivation and fermentation contributed to the maximum adverse impacts. Sensitivity analysis revealed that a reduction in electricity consumption and transportation and an increase in BDO yield could reduce the adverse impacts associated with microbial BDO production.Item Open Access Lignocellulose biohydrogen towards net zero emission: a review on recent developments(Elsevier, 2022-10-12) Laya, Chyi–How; Dharmaraja, Jeyaprakash; Shobana, Sutha; Arvindnarayan, Sundaram; Priya, Retnam Krishna; Jeyakumar, Rajesh Banu; Saratale, Rijuta Ganesh; Park, Young-Kwon; Kumar, Vinod; Kumar, GopalakrishnanThis review mainly determines novel and advance physical, chemical, physico–chemical, microbiological and nanotechnology–based pretreatment techniques in lignocellulosic biomass pretreatment for bio–H2 production. Further, aim of this review is to gain the knowledge on the lignocellulosic biomass pretreatment and its priority on the efficacy of bio–H2 and positive findings. The influence of various pretreatment techniques on the structure of lignocellulosic biomass have presented with the pros and cons, especially about the cellulose digestibility and the interference by generation of inhibitory compounds in the bio–enzymatic technique as such compounds is toxic. The result implies that the stepwise pretreatment technique only can ensure eventually the lignocellulosic biomass materials fermentation to yield bio–H2. Though, the mentioned pretreatment steps are still a challenge to procure cost–effective large–scale conversion of lignocellulosic biomass into fermentable sugars along with low inhibitory concentration.Item Open Access Lignocellulosic biomass conversion via greener pretreatment methods towards biorefinery applications(Elsevier, 2022-11-28) Dharmaraja, Jeyaprakash; Shobana, Sutha; Arvindnarayan, Sundaram; Francis, Rusal Raj; Jeyakumar, Rajesh Banu; Saratale, Rijuta Ganesh; Ashokkumar, Veeramuthu; Bhatia, Shashi Kant; Kumar, Vinod; Kumar, GopalakrishnanLignocellulose biomass during pretreatment releases various compounds, among them the most important is reducing sugars, which can be utilized for the production of biofuels and some other products. Thereby, innovative greener pretreatment techniques for lignocellulosic materials have been considered to open a new door in the aspects of digestibility of the rigid carbohydrate–lignin matrix to reduce the particle size and remove hemicellulose/lignin contents to successfully yield valid bioproducts. This article reviews about the composition of lignocelluloses and emphasizes various green pretreatments viz novel green solvent–based IL and DES steam explosion, supercritical carbon dioxide explosion (Sc–CO2) and co–solvent enhanced lignocellulosic fractionation (CELF) along with suitable mechanistic pathway of LCB pretreatment process. Finally, this article concludes that the existing pretreatments should be redesigned to conquer the demands by large scale production and suggests combined pretreatment methods to carry out various biomass pre–processing.Item Open Access Microbial exopolysaccharide composites in biomedicine and healthcare: trends and advances(MDPI, 2023-04-06) Ahuja, Vishal; Bhatt, Arvind Kumar; Banu, J. Rajesh; Kumar, Vinod; Kumar, Gopalakrishnan; Yang, Yung-Hun; Bhatia, Shashi KantMicrobial exopolysaccharides (EPSs), e.g., xanthan, dextran, gellan, curdlan, etc., have significant applications in several industries (pharma, food, textiles, petroleum, etc.) due to their biocompatibility, nontoxicity, and functional characteristics. However, biodegradability, poor cell adhesion, mineralization, and lower enzyme activity are some other factors that might hinder commercial applications in healthcare practices. Some EPSs lack biological activities that make them prone to degradation in ex vivo, as well as in vivo environments. The blending of EPSs with other natural and synthetic polymers can improve the structural, functional, and physiological characteristics, and make the composites suitable for a diverse range of applications. In comparison to EPS, composites have more mechanical strength, porosity, and stress-bearing capacity, along with a higher cell adhesion rate, and mineralization that is required for tissue engineering. Composites have a better possibility for biomedical and healthcare applications and are used for 2D and 3D scaffold fabrication, drug carrying and delivery, wound healing, tissue regeneration, and engineering. However, the commercialization of these products still needs in-depth research, considering commercial aspects such as stability within ex vivo and in vivo environments, the presence of biological fluids and enzymes, degradation profile, and interaction within living systems. The opportunities and potential applications are diverse, but more elaborative research is needed to address the challenges. In the current article, efforts have been made to summarize the recent advancements in applications of exopolysaccharide composites with natural and synthetic components, with special consideration of pharma and healthcare applications.Item Open Access Molecular biology interventions for activity improvement and production of industrial enzymes(Elsevier, 2020-12-24) Bhatia, Shashi Kant; Vivek, Narisetty; Kumar, Vinod; Chandel, Neha; Thakur, Meenu; Kumar, Dinesh; Yang, Yung-Hun; Pugazhendhi, Arivalagan; Kumar, GopalakrishnanMetagenomics and directed evolution technology have brought a revolution in search of novel enzymes from extreme environment and improvement of existing enzymes and tuning them towards certain desired properties. Using advanced tools of molecular biology i.e. next generation sequencing, site directed mutagenesis, fusion protein, surface display, etc. now researchers can engineer enzymes for improved activity, stability, and substrate specificity to meet the industrial demand. Although many enzymatic processes have been developed up to industrial scale, still there is a need to overcome limitations of maintaining activity during the catalytic process. In this article recent developments in enzymes industrial applications and advancements in metabolic engineering approaches to improve enzymes efficacy and production are reviewedItem Open Access Polyhydroxyalkanoates synthesis using acidogenic fermentative effluents(Elsevier, 2021-11-11) Banu, J. Rajesh; Ginni, G.; Kavitha, S.; Kannah, R. Yukesh; Kumar, Vinod; Kumar, S. Adish; Gunasekaran, M.; Tyagi, Vinay Kumar; Kumar, GopalakrishnanPolyhydroxyalkanoates (PHA) are natural polyesters synthesized by microbes which consume excess amount of carbon and less amount of nutrients. It is biodegradable in nature, and it synthesized from renewable resources. It is considered as a future polymer, which act as an attractive replacement to petrochemical based polymers. The main hindrance to the commercial application of PHA is the high manufacturing cost. This article provides an overview of different cost-effective substrates, their characteristics and composition, major strains involved in economical production of PHA and biosynthetic pathways leading to accumulation of PHA. This review also covers the operational parameters, various fermentative modes including batch, fed-batch, repeated fed-batch and continuous fed-batch systems, along with advanced feeding strategies such as single pulse carbon feeding, feed forward control, intermittent carbon feeding, feast famine conditions to observe their effects for improving PHA synthesis and associated challenges. In addition, it also presents the economic analysis and future perspectives for the commercialization of PHA production process thereby making the process sustainable and lucrative with the possibility of commercial biomanufacturing.Item Open Access Process optimisation for production and recovery of succinic acid using xylose-rich hydrolysates by Actinobacillus succinogenes(Elsevier, 2021-10-28) Jokodola, Esther Oreoluwa; Narisetty, Vivek; Castro, Eulogio; Durgapal, Sumit; Coulon, Frederic; Sindhu, Raveendran; Binod, Parameswaran; Banu, J. Rajesh; Kumar, Gopalakrishnan; Kumar, VinodSuccinic acid (SA) is a top platform chemical obtainable from biomass. The current study evaluated the potential of Actinobacillus succinogenes for SA production using xylose-rich hemicellulosic fractions of two important lignocellulosic feedstocks, olive pits (OP) and sugarcane bagasse (SCB) and the results were compared with pure xylose. Initial experiments were conducted in shake flask followed by batch and fed-batch cultivation in bioreactor. Further separation of SA from the fermented broth was carried out by adapting direct crystallisation method. During fed-batch culture, maximum SA titers of 36.7, 33.6, and 28.7 g/L was achieved on pure xylose, OP and SCB hydrolysates, respectively, with same conversion yield of 0.27 g/g. The recovery yield of SA accumulated on pure xylose, OP and SCB hydrolysates was 79.1, 76.5, and 75.2%, respectively. The results obtained are of substantial value and pave the way for development of sustainable SA biomanufacturing in an integrated biorefinery.Item Open Access 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 KantWorldwide 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.Item Open Access Recent advances in bio-based production of top platform chemical, succinic acid: an alternative to conventional chemistry(Springer Nature, 2024-05-29) Kumar, Vinod; Kumar, Pankaj; Maity, Sunil K.; Agrawal, Deepti; Narisetty, Vivek; Jacob, Samuel; Kumar, Gopalakrishnan; Bhatia, Shashi Kant; Kumar, Dinesh; Vivekanand, VivekanandSuccinic acid (SA) is one of the top platform chemicals with huge applications in diverse sectors. The presence of two carboxylic acid groups on the terminal carbon atoms makes SA a highly functional molecule that can be derivatized into a wide range of products. The biological route for SA production is a cleaner, greener, and promising technological option with huge potential to sequester the potent greenhouse gas, carbon dioxide. The recycling of renewable carbon of biomass (an indirect form of CO2), along with fixing CO2 in the form of SA, offers a carbon-negative SA manufacturing route to reduce atmospheric CO2 load. These attractive attributes compel a paradigm shift from fossil-based to microbial SA manufacturing, as evidenced by several commercial-scale bio-SA production in the last decade. The current review article scrutinizes the existing knowledge and covers SA production by the most efficient SA producers, including several bacteria and yeast strains. The review starts with the biochemistry of the major pathways accumulating SA as an end product. It discusses the SA production from a variety of pure and crude renewable sources by native as well as engineered strains with details of pathway/metabolic, evolutionary, and process engineering approaches for enhancing TYP (titer, yield, and productivity) metrics. The review is then extended to recent progress on separation technologies to recover SA from fermentation broth. Thereafter, SA derivatization opportunities via chemo-catalysis are discussed for various high-value products, which are only a few steps away. The last two sections are devoted to the current scenario of industrial production of bio-SA and associated challenges, along with the author's perspective.Item Open Access Recent advances in fermentative production of C4 diols and their chemo-catalytic upgrading to high-value chemicals(Elsevier, 2023-10-13) Varma, Abhishek R.; Shrirame, Bhushan S.; Maity, Sunil K.; Agrawal, Deepti; Malys, Naglis; Rios-Solis, Leonardo; Kumar, Gopalakrishnan; Kumar, VinodThe current era is witnessing the transition from a fossil-dominated economy towards sustainable and low-carbon green manufacturing technologies at economical prices with reduced energy usage. The biological production of chemical building blocks from biomass using cell factories is a potential alternative to fossil-based synthesis. However, microbes have their own limitations in generating the whole spectrum of petrochemical products. Therefore, there is a growing interest in an integrated/hybrid approach where products containing active functional groups obtained by biological upgrading of biomass are converted via chemo-catalytic routes. The present review focuses on the biological production of three important structural isomers of C4 diols, 2,3-, 1,3-, and 1,4-butanediol, which are currently manufactured by petrochemical route to meet the soaring global market demand. The review starts with justifications for the integrated approach and summarizes the current status of the biological production of these diols, including the substrates, microorganisms, fermentation technology and metabolic/pathway engineering. This is followed by a comprehensive review of recent advances in catalytic upgrading of C4 diols to generate a range of products. The roles of various active sites in the catalyst on catalytic activity, product selectivity, and catalyst stability are discussed. The review also covers examples of integrated approaches, addresses challenges associated with developing end-to-end processes for bio-based production of C4 diols, and underlines existing limitations for their upgrading via direct catalytic conversion. Finally, the concluding remarks and prospects emphasise the need for an integrated biocatalytic and chemo-catalytic approach to broaden the spectrum of products from biomass.Item Open Access A review on the pollution assessment of hazardous materials and the resultant biorefinery products in Palm oil mill effluent(Elsevier, 2023-04-24) Meena, Anu Alias; Merrylin, J.; Banu, Rajesh; Bhatia, Shashi Kant; Kumar, Vinod; Piechota, Grzegorz; Kumar, GopalakrishnanThe voluminous nature of POME is directly associated with environmental hazards and could be turned into biorefinery products. The POME, rich in BOD, COD, and oil and grease, with few hazardous materials such as siloxanes, fatty acid methyl ester, and phenolic compounds may significantly increase the risk of violating the effluent quality standards. Recently, the application of chemical and biological risk assessment that can use electrochemical sensors and microalgae-like species has gained paramount attention towards its remediation. This review describes the existing risk assessment for POME and recommends a novel assessment approach using fish species including invasive ones as suitable for identifying the toxicants. Various physico-chemical and biological treatments such as adsorption, coagulation-flocculation, photo-oxidation, solar-assisted extraction, anaerobic digestion, integrated anaerobic-aerobic, and microalgae cultivation has been investigated. This paper offers an overview of anaerobic technologies, with particular emphasis on advanced bioreactors and their prospects for industrial-level applications. To illustrate, palmitic acid and oleic acid, the precursors of fatty acid methyl ester found in POME pave the way to produce biodiesel with 91.45%. Although there are some challenges in attaining production at an economic scale, this review offers some opportunities that could help in overcoming these challenges.