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Ferulic acid (FA) is a phenolic antioxidant present in plants, which is widely used in the food and cosmetic industry. In the present study, various agricultural wastes such as maize bran, rice bran, wheat bran, wheat straw, sugar cane baggasse, pineapple peels, orange peels, and pomegranate peels were screened for the presence of esterified FA (EFA). Among the sources screened, maize bran was found to contain the highest amount of EFA. Pineapple peels, orange peels, and pomegranate peels were also found to contain traces of EFA. Alkaline extraction of EFA from maize bran was carried out using 2 M NaOH. Response surface methodology (RSM) was used for optimization of EFA extraction, which resulted in a 1.3-fold increase as compared to the unoptimized conventional extraction technique. FA was analyzed by means of high-performance liquid chromatography (HPLC). Purification was carried out by adsorption chromatography using Amberlite XAD-16 followed by preparative high-performance thin-layer chromatography (HPTLC). The recovery of Amberlite XAD-16 purified FA was up to 57.97% with HPLC purity 50.89%. The fold purity achieved was 1.35. After preparative HPTLC, the maximum HPLC purity obtained was 95.35% along with an increase in fold purity up to 2.53.

Ozonolysis is potentially an effective method for pretreating lignocellulosic biomass to improve the production of fermentable sugars via enzymatic hydrolysis. Further understanding of the ozonolysis process and identifying specific lignin structural changes are crucial for improving the pretreatment process. Investigation into pretreatment of wheat straw using ozonolysisis is reported in this paper, with special emphasis on selective modification/degradation of lignin subunits. The ozonolysis was performed for 2 h with less than 60 mesh particles in order to achieve maximum lignin oxidation. The results showed that the lignin structure was significantly modified under these conditions, leading to higher sugar recovery of more than 50% which increased from 13.11% to 63.17% corresponding to the control and ozone treated samples, respectively. Moisture content was found to be an important parameter for improving sugar recovery. Ninety percent (w/w) moisture produced the highest sugar recovery. The concentration of acid soluble lignin in the ozone treated sample increased from 4% to 11% after 2 h treatment. NMR analysis revealed that the S2/6 and G2 lignin units in the wheat straw were most prone to oxidation by ozone as the concentration of aromatic units decreased while the carboxylic acids became more abundant. The experimental data suggest the degradation of β-O-4 moieties and aromatic ring opening in lignin subunits. The pyrolysis-gas chromatography/mass spectrometry results revealed that the rate of lignin unit degradation was in the following order: syringyl > guaiacyl > p-hydroxyphenyl. Long ozone exposure resulted in few condensed lignin structure formation. In addition, the formation of condensed units during this process increased the activation energy from ASTM-E, 259.74 kJ/mol; Friedman-E, 270.08 kJ/mol to ASTM-E, 509.29 kJ/mol; Friedman-E, 462.17 kJ/mol. The results provide new information in overcoming lignin barrier for lignocellulose utilization.

The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials using microorganisms is gaining importance in the field of nanotechnology. In the present study, gold nanoparticles have been synthesized by reduction of aqueous gold ions using the culture supernatant of Aspergillus niger NCIM 616. The synthesis of the gold nanoparticles was monitored by UV-visible spectroscopy. The particles thereby obtained were characterized by UV, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The stability of the synthesized gold nanoparticles was analyzed by zeta potential measurement. Treatment of the fungal supernatant with aqueous Au + ions produced nanoparticles with an average particle size of 12.79 ± 5.61 nm. Different characterization studies showed that the extracellular enzyme secreted by Aspergillus niger NCIM 616 might be responsible for both formation and capping of the metal nanoparticles.

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