Kalyan Gayen

Every year, approximately 40% of post‐harvest fruits and vegetables are spoiled as a consequence of inadequate storage facilities and poor logistics, including substandard packaging, handling, and transportation. Application of organic coating on the surface of fruits and vegetables extends the shelf‐life of them. The spoilage of fruits and vegetables not only results in monetary losses but also poses a waste management challenge. This study demonstrated the use of extracted cellulose from waste biomass (banana stem) for the preparation of coating formulation. Extraction yield of cellulose from banana stem was found to be 28.52% with > 90% purity. FTIR analysis confirmed the presence of distinctive cellulose bands in the transmittance spectrum, and XRD analysis had shown the crystallinity index 78.32% in the extracted cellulose. Extracted cellulose was converted into carboxymethyl cellulose (CMC) with a degree of substitution of 1.89. Coating formulations were prepared with the synthesized CMC and applied to the locally grown tomatoes. Different physicochemical characteristics of the tomatoes were evaluated to estimate the efficiency of the applied coating. Application of coating formulation on the tomatoes had shown increase in the shelf‐life of 12 days at room temperature and 18 days at 4 ^° C. This technique is helpful to reduce health hazards, lessen environmental pollution, and increase agricultural sector profitability.

Lignin of lignocellulosic biomass holds tremendous potential for producing chemicals and biomaterials. However, unlocking lignin’s utility has been challenging until the advent of lignin nanoparticles (LNPs). LNPs have revolutionized the application of lignin, especially in fields like medicine and pharmaceuticals, by enabling efficient delivery of active bactericidal agents, such as silver ions. Silver ions possess broad-spectrum antibiotic properties against various microbial species. Yet, their clinical and pharmaceutical applications have been limited due to issues like toxicity and inefficient delivery mechanisms. In this study, lignin was extracted from sugarcane bagasse through alkali treatment and acid precipitation. The experimental results indicated that treating the biomass with a 5% NaOH solution followed by precipitation with 6 M H ₂ SO ₄ yielded the highest lignin content of 23.76%. Characterization of the isolated lignin and synthesized LNPs revealed significant structural and morphological features. FTIR spectra confirmed the presence of characteristic lignin functional groups. DLS analysis showed that the average particle size of LNP@Ag was around 323.7 nm with a polydispersity index (PDI) of 0.17, indicating uniform nanoparticle distribution. SEM imaging revealed irregular morphology of the LNP and rough morphology of LNP@Ag, while EDX confirmed successful silver immobilization in LNP@Ag by detecting a distinct Ag signal. The antimicrobial testing suggested that LNP@Ag exhibited potential antibacterial activity against Escherichia coli and Staphylococcus aureus . Further microtiter calorimetric assay analysis of bactericidal activity against E. coli was performed. Overall, this study underscores the potential of lignin-based nanoparticles, particularly LNP@Ag, as promising candidates for antimicrobial applications, addressing key challenges associated with silver ion delivery and toxicity in clinical and pharmaceutical settings. Graphical abstract

Microalgae-derived extracellular polysaccharides (EPSs) have emerged as a promising biological macromolecule for its application in pharmaceutical and biotechnological fields due to its diverse physicochemical and biological activities. In this study, an isolated microalgae (Asterarcys quadricellulare) was cultured in photobioreactor under the light condition by maintaining 14:10 photoperiod to produce EPSs. The yield of EPSs was found 0.392 ± 0.027 gL^-1. The biochemical analysis of extracted EPSs had shown the presence of uronic acid (0.42 ± 0.05%), phosphate (0.312 ± 0.013%), sulfate (0.531 ± 0.04%), and carbohydrates (60.33 ± 0.02%) containing glucose and galactose with a ratio of 3.24:1. FTIR analysis of EPSs revealed characteristic glycosidic bond between sugar monomer at 880 and 834 cm^-1. Therefore, extracted EPS was a complex heteropolysaccharide structure. Surface morphology of EPSs revealed the presence of a large number of symmetrical and regular filamentous repeating units. XRD analysis had shown the crystalline nature of extracted EPSs with crystallinity index of 51.73%. Antimicrobial activity of EPSs was evaluated against Bacillus subtilis (gram positive) and Escherichia coli (gram negative) bacteria. Escherichia coli had showed 46.67 ± 0.002% growth inhibition and 33.3 ± 2.5% (P < 0.01) reduction in the viable cell count compared to the negative control. Results demonstrated the promise of microalgal EPSs in the biotechnology and pharmaceutical sectors for selective antimicrobial application.

Traditional protein and pigment (e.g., chlorophyll) sources are becoming insufficient due to the rapid rise of the global population in modern civilization. Microalgae offer a promising solution for protein and chlorophyll sources due to their higher productivity than terrestrial plants. This study aims to optimize the cultivation conditions for Desmodesmus subspicatus, a microalgal strain containing ∼60% protein and 4% chlorophyll, to enhance biomass, protein and chlorophyll productivity. A Taguchi Orthogonal Array (TOA) was used for systematic optimization of BG-11 medium components. Further experiments assessed the effects of light intensity and different carbon and nitrogen sources. Under optimized BG-11 conditions, biomass increased 1.3-fold, with protein and chlorophyll productivity rising 2.25 and 1.92-fold, respectively. Supplementation with carbon and nitrogen sources under varying light (84-504 µmol m^-2 s^-1) further enhanced yields by 1.6-fold. Glycine proved to be the most effective nitrogen source, while cellulose as a carbon source resulted in 2.4-fold higher biomass, 7.3-fold higher protein, and 2.3-fold higher chlorophyll. Cytotoxicity assessment of the extracted chlorophyll revealed over 94% A549 cell viability at concentrations up to 100 µg/mL, confirming its biocompatibility. Therefore, Desmodesmus subspicatus has promise as a sustainable source of proteins and chlorophylls in the nutraceutical and food industries.

Microalgae are under research focus for the simultaneous production of biomolecules (e.g., carbohydrates, proteins, pigments and lipids) and bioremediation of toxic substances from wastewater. The current study explores the capability of indigenously isolated microalgae (Desmodesmus subspicatus) for the phycoremediation of As(III) and Cr(VI). Variation of biomolecules (carbohydrate, protein, lipid and chlorophyll) was investigated during phycoremediation. D. subspicatus survived up to the toxicity level of 10 mg/L for As(III) and 0.8 mg/L for Cr(VI). A 70% decline in carbohydrate accumulation was observed at 10 mg/L of As(III). An increased content of proteins (+ 28%) and lipids (+ 32%) within the cells was observed while growing in 0.5 and 0.2 mg/L of As(III) and Cr(VI) respectively. A decrease in carbohydrate accumulation was noted with increasing Cr(VI) concentration, and the lowest (− 44%) was recorded at 0.8 mg/L Cr(VI). D. subspicatus showed an excellent maximum removal efficiency for Cr(VI) and As(III) as 77% and 90% respectively. Graphical abstract

Microalgae are under research focus for the simultaneous production of biomolecules (e.g., biofuels) and bioremediation of toxic materials from wastewater. The current study explores the capability of indigenously isolated microalgae (Desmodesmus subspicatus) for phycoremediation As(III) and Cr(VI) along with the production of biomolecules by alternating its extracellular and intracellular compositions.Desmodesmus subspicatussurvived up to the toxicity level of 10 mg/L for As(III) and 0.8 mg//L for Cr(VI). A decline in carbohydrate accumulation (⁓70%) at 10 mg/L of As(III) concentration was obtained. An increased content of protein (⁓28%) and lipid (by ⁓32%) within the cells ofDesmodesmus subspicatuswas observed when grown in 0.5 and 0.2 mg/L As(III) concentrations respectively. A descending trend in carbohydrate accumulation was noted with increasing Cr(VI) concentration and the least (~44%) was recorded at 0.8 mg/L Cr(VI).Desmodesmus subspicatusshowed an excellent maximum removal efficiency for Cr(VI) and As(III) as 77% and 90% respectively.

Cellulosic aerogels are sustainable, biodegradable, and ultra-light porous materials with three-dimensional networks having high specific surface area. Depending on the source of precursor materials, they are categorized into plant-based aerogel, bacterial cellulosic aerogel. Different types of aerogels are also produced from microcrystalline cellulose (MCC), nanocrystalline cellulose (NCC), cellulose microfibril (CMF) and cellulose nanofibril (CNF). Furthermore, inorganic and organic substances are embedded to produce hybrid aerogel or composite aerogel for the enhancement of its performance in various fields. Mixing, gelation, solvent exchange, and drying (e.g., super critical carbon dioxide or freeze drying) are the basic steps involved in cellulosic aerogel synthesis. Based on the composition of precursors during aerogel synthesis, cellulosic aerogels have broad applications in various fields such as adsorbents, electrodes, sensors, captive deionization materials, catalysts, drug delivery, thermal and sound insulating materials. This review provided consolidated information on: (i) classification of cellulosic aerogels based on the sources of raw materials, (ii) processes involved to produce the cellulosic aerogel, (iii) cellulosic aerogel synthesized from MCC, NCC, CMF and CNF, (iv) nano particle doped cellulosic aerogel, and (v) its application in various field with future perspectives.