BITS Faculty Publications
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Item Sustainable valorization of macroalgae residual biomass, optimization of pyrolysis parameters and life cycle assessment(Elsevier, 2024-04) Sangwan, Kuldip Singh; Raghuvanshi, SmitaThe major challenges for the current climate change issue are an increase in global energy demand, a limited supply of fossil fuels, and increasing carbon footprints from fossil fuels, which have necessitated the exploration of sustainable alternatives to fossil fuels. Biorefineries offer a promising path to sustainable fuel production, converting biomass into biofuels using diverse technologies. Aquatic biomass, such as macroalgae in this context, represents an abundant and renewable biomass resource that can be cultivated from water bodies without competing with traditional agricultural land. Despite this, the potential of macroalgae for biofuel production remains largely untapped, with very limited studies addressing their viability and efficiency. This study investigates the efficient conversion of unexplored macroalgae biomass through a biorefinery process that involves lipid extraction to produce biodiesel, along with the production of biochar and bio-oil from the pyrolysis of residual biomass. To improve the effectiveness and overall performance of the pyrolysis system, Response Surface Methodology (RSM) was utilized through a Box-Behnken design to systematically investigate how alterations in temperature, reaction time, and catalyst concentration influence the production of bio-oil and biochar to maximize their yields. The results showed the highest bio-oil yield achieved to be 36 %, while the highest biochar yield reached 45 %.Item Direct saponification of wet microalgae by methanolic potassium hydroxide using acetone as co-solvent(Elsevier, 2019-02) Verma, Sanjay KumarThe fatty acids of microalgae are promising source of biodiesel and omega-3 fatty acids. The objective of this study is extraction of fatty acids from wet Dunaliela salina by direct saponification using methanolic potassium hydroxide and a suitable co-solvent. The study identified acetone as an efficient co-solvent for saponification of wet microalgal biomass by methanolic potassium hydroxide. The presence of acetone in methanolic KOH saponification produced 24% more fatty acid than its absence. Further optimization of concentration of acetone (80% v/v), concentration of potassium hydroxide (0.1% v/v) and solvent-dry biomass ratio (75:1) resulted in a maximum yield of 98% fatty acid. The proposed acetone assisted saponification of wet microalgal biomass could serve as an energy efficient route for fatty acid production since the reaction happens under room temperature and normal atmospheric pressure without any cell lysis or drying the biomass.Item Sweet sorghum as biofuel feedstock: recent advances and available resources(Springer Nature, 2017-06) Sharma, RitaSweet sorghum is a promising target for biofuel production. It is a C4 crop with low input requirements and accumulates high levels of sugars in its stalks. However, large-scale planting on marginal lands would require improved varieties with optimized biofuel-related traits and tolerance to biotic and abiotic stresses. Considering this, many studies have been carried out to generate genetic and genomic resources for sweet sorghum. In this review, we discuss various attributes of sweet sorghum that make it an ideal candidate for biofuel feedstock, and provide an overview of genetic diversity, tools, and resources available for engineering and/or marker-assisting breeding of sweet sorghum. Finally, the progress made so far, in identification of genes/quantitative trait loci (QTLs) important for agronomic traits and ongoing molecular breeding efforts to generate improved varieties, has been discussed.Item Phylogenomic Analysis of R2R3 MYB Transcription Factors in Sorghum and their Role in Conditioning Biofuel Syndrome(Bentham Science, 2020) Sharma, RitaLarge scale cultivation of sorghum for food, feed, and biofuel requires concerted efforts for engineering multipurpose cultivars with optimised agronomic traits. Due to their vital role in regulating the biosynthesis of phenylpropanoid-derived compounds, biomass composition, biotic, and abiotic stress response, R2R3-MYB family transcription factors are ideal targets for improving environmental resilience and economic value of sorghum.Item Oxidative decarboxylation of fatty acids to terminal alkenes by a membrane-bound metalloenzyme, UndB(CUP, 2023-04) Sidhu, Jagpreet SinghBiosynthetically produced alkenes are high-value molecules that can serve as ‘drop-in’ replacements for fossil fuels. Alkenes are also heavily used in the polymer, lubricant, and detergent industries. UndB is the only known membrane-bound fatty acid decarboxylase that catalyzes the conversion of fatty acids to terminal alkenes at the highest reported in vivo titers. However, the enzyme remains poorly understood and enigmatic. Here, we demonstrate the first-time purification of UndB and establish that it is an oxygen-dependent, non-heme diiron enzyme that engages conserved histidine residues at the active site. We also identify redox partners that support the activity of UndB and determine the enzyme's substrate specificity and kinetic properties. We detect CO2 as the co-product of the UndB-catalyzed reaction and provide the first evidence in favor of the hydrogen atom transfer (HAT) mechanism of the enzyme. Our findings decipher the biochemistry of an enigmatic metalloenzyme that catalyzes 1-alkene biosynthesis at the membrane interface with the highest known efficiency.Item Technoeconomic Analysis of Biorefinery Processes for Biofuel and Other Important Products(Wiley, 2020-01-10) Srinivas, AppariIn this chapter, a technoeconomic analysis of biofuels and other value-added chemicals production from lignocellulosic biomass is presented. Biofuel and other products derived from lignocellulosic biomass are also called second-generation products, which have energetic, economic, and environmental advantages in comparison to primary products such as starch or sugar. The conversion of feedstock into products is an energy-intensive process which requires various unit operations that require various forms of energy such as current, heat in the form of steam, cooling water, refrigeration, etc. The material and energy streams play a vital role in the estimation of process economy. Technoeconomic evaluations allow organizations to decide on which projects to continue and how to optimize the design to maximize profits. In this chapter, we describe the technoeconomic modeling approach for the conversion of biomass into products. This approach is widely used in most of the case studies, although with a compact timeline and with further extrapolations relating to geographical areas. Discounted and nondiscounted cash flow probability criteria used for estimating rate of return, payback period, net present value, and minimum product selling price are discussed.Item Energetic assessment of fixation of CO2 and subsequent biofuel production using B. cereus SM1 isolated from sewage treatment plant(Springer, 2016-04-13) Gupta, Suresh; Raghuvanshi, Smita; Mishra, SomeshThe ongoing work on global warming resulting from green house gases (GHGs) has led to explore the possibility of bacterial strains which can fix carbon dioxide (CO2) and can generate value-added products. The present work is an effort in this direction and has carried out an exhaustive batch experiments for the fixation of CO2 using B. Cereus SM1 isolated from sewage treatment plant (STP). The work has incorporated 5-day batch run for gaseous phase inlet CO2 concentration of 13 ± 1 % (%v/v). 84.6 (±5.76) % of CO2 removal was obtained in the gaseous phase at mentioned CO2 concentration (%v/v). Energetic requirement for CO2 fixation was assessed by varying Fe[II] ion concentration (0–200 ppm) on the per-day basis. The cell lysate obtained from CO2 fixation studies (Fe[II] ion = 100 ppm) was analyzed using Fourier transformation infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC–MS). This analysis confirmed the presence of fatty acids and hydrocarbon as valuable products. The hydrocarbons were found in the range of C11–C22 which is equivalent to light oil. The obtained fatty acids were found in the range of C11–C19. The possibility of fatty acid conversion to biodiesel was explored by carrying out the transesterification reaction. The yield of biodiesel was obtained as 86.5 (±0.048) % under the transesterification reaction conditions. Results of this research work can provide the valuable information in the implementation of biomitigation of CO2 at real scenario.Item Phylogenomic Analysis of R2R3 MYB Transcription Factors in Sorghum and their Role in Conditioning Biofuel Syndrome(Bentham Science, 2020) Sharma, RitaBackground: Large scale cultivation of sorghum for food, feed, and biofuel requires concerted efforts for engineering multipurpose cultivars with optimised agronomic traits. Due to their vital role in regulating the biosynthesis of phenylpropanoid-derived compounds, biomass composition, biotic, and abiotic stress response, R2R3-MYB family transcription factors are ideal targets for improving environmental resilience and economic value of sorghum. Methods: We used diverse computational biology tools to survey the sorghum genome to identify R2R3-MYB transcription factors followed by their structural and phylogenomic analysis. We used inhouse generated as well as publicly available high throughput expression data to analyse the R2R3 expression patterns in various sorghum tissue types. Results: We have identified a total of 134 R2R3-MYB genes from sorghum and developed a framework to predict gene functions. Collating information from the physical location, duplication, structural analysis, orthologous sequences, phylogeny, and expression patterns revealed the role of duplications in clade-wise expansion of the R2R3-MYB family as well as intra-clade functional diversification. Using publicly available and in-house generated RNA sequencing data, we provide MYB candidates for conditioning biofuel syndrome by engineering phenylpropanoid biosynthesis and sugar signalling pathways in sorghum.Item Direct saponification of wet microalgae by methanolic potassium hydroxide using acetone as co-solvent(Elsiever, 2019-02) Verma, Sanjay KumarThe fatty acids of microalgae are promising source of biodiesel and omega-3 fatty acids. The objective of this study is extraction of fatty acids from wet Dunaliela salina by direct saponification using methanolic potassium hydroxide and a suitable co-solvent. The study identified acetone as an efficient co-solvent for saponification of wet microalgal biomass by methanolic potassium hydroxide. The presence of acetone in methanolic KOH saponification produced 24% more fatty acid than its absence. Further optimization of concentration of acetone (80% v/v), concentration of potassium hydroxide (0.1% v/v) and solvent-dry biomass ratio (75:1) resulted in a maximum yield of 98% fatty acid. The proposed acetone assisted saponification of wet microalgal biomass could serve as an energy efficient route for fatty acid production since the reaction happens under room temperature and normal atmospheric pressure without any cell lysis or drying the biomass.Item Construction of a rice glycoside hydrolase phylogenomic database and identification of targets for biofuel research(Frontiers, 2013) Sharma, RitaGlycoside hydrolases (GH) catalyze the hydrolysis of glycosidic bonds in cell wall polymers and can have major effects on cell wall architecture. Taking advantage of the massive datasets available in public databases, we have constructed a rice phylogenomic database of GHs (http://ricephylogenomics.ucdavis.edu/cellwalls/gh/). This database integrates multiple data types including the structural features, orthologous relationships, mutant availability, and gene expression patterns for each GH family in a phylogenomic context. The rice genome encodes 437 GH genes classified into 34 families. Based on pairwise comparison with eight dicot and four monocot genomes, we identified 138 GH genes that are highly diverged between monocots and dicots, 57 of which have diverged further in rice as compared with four monocot genomes scanned in this study. Chromosomal localization and expression analysis suggest a role for both whole-genome and localized gene duplications in expansion and diversification of GH families in rice. We examined the meta-profiles of expression patterns of GH genes in twenty different anatomical tissues of rice. Transcripts of 51 genes exhibit tissue or developmental stage-preferential expression, whereas, seventeen other genes preferentially accumulate in actively growing tissues. When queried in RiceNet, a probabilistic functional gene network that facilitates functional gene predictions, nine out of seventeen genes form a regulatory network with the well-characterized genes involved in biosynthesis of cell wall polymers including cellulose synthase and cellulose synthase-like genes of rice. Two-thirds of the GH genes in rice are up regulated in response to biotic and abiotic stress treatments indicating a role in stress adaptation. Our analyses identify potential GH targets for cell wall modification.