Laccase mediated delignification of pineapple leaf waste: an ecofriendly sustainable attempt towards valorization

Background

Escalating energy security, burgeoning population and rising costs of fossil fuels have focussed our attention on tapping renewable energy sources. As the utilization of food crops for biofuel production culminates into food vs. fuel dilemma, there is an intensive need for alternatives. Production of biofuels from lignocellulosic biomass owing to its profuse availability and high holocellulose content is a promising area for research.

Results

In the present study, pineapple leaf, an agro-industrial waste was pretreated with laccase to enhance the enzymatic digestibility of the substrate for improved production of reducing sugar. Variables determining enzymatic delignification of pineapple leaf waste have been optimized by response surface methodology based on central composite design. Maximum delignification of 78.57%(w/w) resulted in reducing sugar of 492.33 ± 3.1 mg/g in 5.30 h. The structural changes in pineapple leaf waste, after laccase treatment, were studied through Fourier transformed infrared spectroscopy, X-ray diffraction and Scanning electron microscopy. Specific surface area, pore volume, and pore diameter of the substrate were studied using the Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods and found a significant increase in the aforementioned parameters after delignification.

Conclusion

Laccase mediated delignification of pineapple leaf waste is a cleaner sustainable process for enhanced production of reducing sugar which can accomplish the demand for biofuels.

Synthesis of ion-imprinted polymer-decorated SBA-15 as a selective and efficient system for the removal and extraction of Cu(ii) with focus on optimization by response surface methodology

Ion-imprinted polymer-decorated SBA-15 (SBA-15-IIP) for the adsorption of copper was synthesized and characterized using different techniques, including FT-IR, XRD, TG/DTA, SEM, BET, and TEM.

α-Amylase immobilization onto functionalized graphene nanosheets as scaffolds: Its characterization, kinetics and potential applications in starch based industries

α-Amylase is imperative for starch and its deriviatized industries. Functionalized graphene sheets were tailored and optimized as scaffold for α-amylase immobilization using Response Surface Methodology based on Box–Behnken design, with an overall immobilization efficiency of 85.16%. Analysis of variance provided adequacy to the mathematical model for further studies. Native and immobilized functionalized graphene were characterized using transmission and scanning electron microscopy, followed by Fourier transform infrared (FTIR) spectroscopy. Wheat α-amylase conjugated with functionalized graphene sheets were visually evident on transmission and scanning micrographs while the FTIR spectra showed interplay of various chemical interactions and bonding, during and after immobilization. Optimum pH and optimum temperature for immobilized enzyme though remained unchanged but showed broader range whereas K_m showed a slight decrease (1.32 mg/mL). It also showed enhanced thermal and storage stability and retained 73% residual activity after 10 uses. These ensemble of properties and non-toxic nature of functionalized graphene, makes it viable to be absorbed commercially in starch processing industries.

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α-Amylase was optimally anchored on functionalized graphene nanosheets using RSM.

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This multipoint attachment resulted in improved features for its industrial viability.

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With decreased K_m, bioconjugate ascertains increased affinity for substrate hydrolysis.

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Showed improved thermostability, reusability and storage stability over free enzyme.

Microwave-assisted one-step extraction-derivatization for rapid analysis of fatty acids profile in herbal medicine by gas chromatography-mass spectrometry

A rapid and practical microwave-assisted one-step extraction-derivatization (MAED) method was developed for gas chromatography-mass spectrometry analysis of fatty acids profile in herbal medicine. Several critical experimental parameters for MAED, including reaction temperature, microwave power and the amount of derivatization reagent (methanol), were optimized with response surface methodology. The results showed that the chromatographic peak areas of total fatty acids and total unsaturated fatty acids content obtained with MAED were markedly higher than those obtained by the conventional Soxhlet or microwave extraction and then derivatization method. The investigation of kinetics and thermodynamics of the derivatization reaction revealed that microwave assistance could reduce activation energy and increase the Arrhenius pre-exponential factor. The MAED method simplified the sample preparation procedure, shortened the reaction time, but improved the extraction and derivatization efficiency of lipids and reduced ingredient losses, especially for the oxidization and isomerization of unsaturated fatty acids. The simplicity, speed and practicality of this method indicates great potential for high throughput analysis of fatty acids in natural medicinal samples.