Bioprospecting microwave-alkaline hydrolysate cocktail of defatted soybean meal and jackfruit peel biomass as carrier additive of molasses-alginate-bead biofertilizer

The extraction of soluble hydrolysate protein and sugar from a biomass cocktail of defatted soybean meal (DSM) and jackfruit peel (JP) was examined using microwave-alkaline hydrolysis by varying the NaOH concentrations (0.04–0.11 M) and residence times (2–11 min). Based on the central composite design, the optimized parameters were achieved at 0.084 M NaOH concentration (100 mL), for 8.7 min at 300 W microwave power level to obtain the highest protein (5.31 mg/mL) and sugar concentrations (8.07 mg/mL) with > 75% recovery. Both raw and detoxified hydrolysate (using activated carbon) were correspondingly biocompatible with Enterobacter hormaechei strain 40a (P > 0.05) resulting in maximal cell counts of > 10 log CFU/mL. The optimized hydrolysate was prepared as an additive in molasses-alginate bead encapsulation of strain 40a. Further evaluation on phosphate and potassium solubilization performance of the encapsulated strain 40a exhibited comparable results with those of free cell counterpart (P > 0.05). The DSM-JP hydrolysate cocktail holds potential as a carrier additive of encapsulated-cell bead biofertilizers in order to sustain bacterial cell quality and consequently improve crop growth and productivity.

Microfluidic Overhauser DNP chip for signal-enhanced compact NMR

Nuclear magnetic resonance at low field strength is an insensitive spectroscopic technique, precluding portable applications with small sample volumes, such as needed for biomarker detection in body fluids. Here we report a compact double resonant chip stack system that implements in situ dynamic nuclear polarisation of a 130 nL sample volume, achieving signal enhancements of up to − 60 w.r.t. the thermal equilibrium level at a microwave power level of 0.5 W. This work overcomes instrumental barriers to the use of NMR detection for point-of-care applications.

A new rapid synthesis of potassium borates by microwave irradiation

Potassium borates are one of the minor groups of boron minerals with its distinct non-linear optical properties. In this study, potassium borate compound of santite (KB5O8·4H2O) are synthesized using potassium carbonate (K2CO3) and boric acid (H3BO3) with a new and rapid method of microwave irradiation. The synthesized minerals are characterized by various analysis techniques of X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). Three parameters of “microwave power level”, “reaction times” and “reaction stoichiometric constants (elemental potassium to boron ratios)” are determined for the optimum synthesis of potassium borate within the four step. At the end of the step 4, optimum products are obtained as santite type potassium borate. Synthesized potassium borates Raman bands are in mutual agreement with the boron compounds and the overall reaction yields to potassium borates are very high compared with the lower reaction times.

Study of color kinetics of banana (Musa cavendish) under microwave drying by application of image analysis

Microwave drying works on the volumetric heating concept promoted by electromagnetic radiation at 0.915 or 2.450 GHz. In this study, banana ( Musa Cavendish) was taken as the sample and treated under microwave drying. The effect of two process variables, namely slice thickness (2, 3.5, and 5 mm) and microwave power (180 W, 360 W, and 540 W), were studied on drying kinetics and color kinetics. It was observed that the inverse variation relationship exists between drying time and microwave power level while drying time and slice thickness exhibited a direct variation relationship. A Computer Vision System (CVS) was developed to measure the color values of banana in CIELab space using an algorithm written in MATLAB software. Once the color parameters were obtained, they were fitted in First and Zero-order kinetic models. Both models were found to describe the color values adequately. This study concludes that microwave drying is a promising dehydration technique for banana drying that reduces the significant time of drying. Application of CVS is an excellent approach to measure the surface color of banana.

Microfluidic Overhauser DNP Chip for Signal-enhanced Compact NMR

Nuclear magnetic resonance at low field strength is an insensitive spectroscopic technique, precluding portable applications with small sample volumes, such as needed for biomarker detection in body fluids. Here we report a compact double resonant chip stack system that implements in situ dynamic nuclear polarisation of a 130 nL sample volume, achieving a signal enhancement of 54 w.r.t. the thermal equilibrium level at a microwave power level of 0.5W. This work overcomes instrumental barriers to the use of NMR detection for point-of-care applications.

A Modified Preparation of Cellulosic-Absorbent Resin for Cu2+ Removal under Microwave Irradiation

The absorbent resin for Cu2+ removal was prepared under microwave irradiation through grafting acrylamide (AM) and acrylic acid (AA) to cellulose. The initiator is a kind of redox system composed of potassium persulfate/sodium thiosulfate. The crosslinking agent is N,N′-methylene bisacrylamide. The optimal reaction conditions are as follows: the ratio of AA to cellulose is 10 : 1, initiator to AA is 0.65 wt%, crosslinking agent to AA is 1.0 wt%, neutralization degree of AA is 75%, microwave power level is 320 W, and time is 300 s. The maximum absorption capability of the resin is 65 mg·g−1. Different from previous studies, the reaction was carried out without the protection of nitrogen and troublesome posttreatment. The product was obtained directly by one-step synthesis without purification and drying of the crude product. The pollution and cost caused by organic solvent are avoided, and the whole preparation period is shortened deeply. Moreover, the time of absorption equilibrium is shorter. In a word, the preparation in this paper has the obvious advantages, such as simple process, short time, no pollution, low-energy, and low-cost.

Experimental study on microwave torrefaction of lignocellulosic biomass

This paper presents preliminary research of lignocellulosic biomass torrefaction by using microwave heating. The experimental setup was developed using a microwave oven with 2.45 GHz frequency. The torrefaction effect was studied by varying the microwave power level (160-480 W) and reaction time (5-30 min). The two Polish biomass feedstock, agricultural residue (wheat straw) and energy crop (Miscanthus giganteus) were used in this study. Fuel properties like H/C and O/C ratio were assessed from elemental composition. Mass yield and energy yield of the torrefied fuels were also determined. It was found that higher microwave power levels contributed to higher heating rate and reaction temperature, and thus produced the torrefied biomass with higher heating value and lower H/C and O/C ratios.

Application of Plackett Burman Design for Antioxidant Extraction from Actinodaphne sesquipedalis leaves

Actinodaphne sesquipedalis Hook. F. Var. Glabra (Kochummen), also known as “Medang payung” by the Malay people, belongs to the Lauraceae family. In this study, a Plackett-Burman design was used to evaluate the significant extraction parameters in achieving maximum DPPH radical scavenging activity from ethanol leaves extract of A. sesquipedalis. Microwave-assisted extraction technique was employed using aqueous ethanol. The independent parameters were microwave power level (30–60 W), feed-to-solvent ratio (1:30 g/ml), irradiation time (30-90 s) and ethanol concentration (20–80%). Amongst the examined parameters, ethanol concentration, microwave power level, and irradiation/extraction time were significant, whereas, feed-to-solvent ratio was insignificant. Therefore, antioxidants from the ethanolic extraction leaves of A. sesquipedalis using microwave technique are significantly affected by ethanol concentration, irradiation time and microwave power.