Glucose production from potato peel waste under microwave irradiation

Transforming Agro-Industrial Waste into Bioplastic Coating Films

Addressing the environmental impact of agro-industrial waste, this study explores the transformation of banana, potato, and orange peels into bioplastics suitable for thin coating films. We prepared six extracts at 100 g/L, encompassing individual (banana peel, BP; orange peel, OP; and potato peel, PP) and combined [BP/OP, BP/PP, and BP/OP/PP] formulations, with yeast mold (YM) medium serving as the control. Utilizing the spin-coating method, we applied 1 mL of each sample at 1000 rpm for 1 min to create the films. Notably, the OP extract demonstrated a twofold increase in bioplastic yield (860.33 mg/L) compared to the yields of BP (391.43 mg/L), PP (357.67 mg/L), BP/OP (469.40 mg/L), BP/PP (382.50 mg/L), BP/OP/PP (272.67 mg/L), and YM (416.33 mg/L) extracts. Atomic force microscopy analysis of the film surfaces revealed a roughness under 8 nm, with the OP extract recording the highest at 7.0275 nm, whereas the BP/OP mixture exhibited the lowest roughness at 0.2067 nm and also formed the thinnest film at 6.5 nm. With R2 trend values exceeding 0.9950, the films exhibited water vapor permeability values ranging from 3.05 × 10-3 to 4.44 × 10-3, with the OP film being the least permeable and the BP/PP films the most permeable. The OP film demonstrated the lowest solubility in both water and ethanol with values of 64.71 and 1.05%, respectively. The solubilities of all films were above 60% in water and below 4% in ethanol. Furthermore, the films exhibited antimicrobial efficacy against both Gram-positive and Gram-negative bacteria. Our findings confirm the potential of utilizing banana, orange, and potato peels as viable substrates for eco-friendly bioplastics in thin-film applications.

Sensory, textural, physico-chemical and enzymatic characterization of melted cheese with added potato and carrot peels

Food waste is one of the biggest societal problems in the globe due to its detrimental consequences on the environment. According to estimates from the Food and Agriculture Organization, this comes to about 1.3 billion tonnes per year. The current study aims to produce sustainable food products with high nutritional value by incorporating food waste. For the extraction of economically relevant products such as dietary fibers, biopolymers, natural antioxidants, and food additives, potato and carrot peel represent an inexpensive, valuable, and conveniently available resource. Cheese is a functional dairy product that people eat for its high nutritional content, which aids in the treatment of conditions including diabetes, obesity, hypertension, and digestive problems in addition to giving them energy. Thus a control sample and 10 samples of melted cheese with various amounts of potato and carrot peelings were prepared. To explore the nutritional value of potato and carrot peels in melted cheese, an analysis was conducted on the fluctuation of physicochemical (acidity, pH, dry matter, water activity, and salt content) and enzymatic (L-lactic acid, lactose, D-glucose, and D-galactose) parameters. Consumer acceptability of the products was assessed by textural and sensory analysis. During the whole storage period, the samples of melted cheese with potato and carrot peels recorded higher values than the control sample, the results obtained for them being better. Samples with added potato or carrot wastes were more stable over time, as compared to control samples.

Role of the substrate on Ni inhibition in biological sulfate reduction

In treating mine-impacted waters using sulfate-reducing bacteria (SRB), metal inhibition and substrate selection are important factors affecting the efficiency of the bioprocess. This work investigated the role of the substrate (i.e. lactate, formate, glycerol and glucose) on Ni inhibition to SRB with sulfate-reducing activity tests at initial pH 5, 7 and 9 and 100 mg/L of Ni. Results indicated that the type of substrate was a significant factor affecting Ni inhibition in SRB, which was the most negligible in the lactate system, followed by glycerol, glucose, and formate. Although less significant, Ni inhibition also varied with the pH, leading for instance, to a reduction of 77% in the sulfate reducing activity for the formate system, but only of 28% for lactate at pH 5. The added substrate also influenced the precipitation kinetics and the characteristics of the precipitates, reaching Ni precipitation extents above 95%, except for glucose (83.2%).

Conversion of food and kitchen waste to value-added products

Food and kitchen waste - omnipresent in every corner of the world serve as an excellent source of value added products owing to high organic content. Regardless of existence of various traditional methods of land filling or biogas production used to harness food waste energy, effective conversion of food to valuable resources is often challenged by its heterogenous nature and high moisture content. The current paper tries to lay down the prospects and consequences associated with food waste management. The various social, economical and environmental concerns associated with food waste management especially in terms of green house gas emission and extended rate of leachate generation also has been discussed. The difficulties in proper collection, storage and bioconversion of food waste to valuable by-products are pointed as a big hurdle in proper waste management. Finally, the wide array of value added products developed from food waste after pretreatment are also enlisted to emphasis the prospects of food waste management.

Proton-Enhanced Dielectric Properties of Polyoxometalates in Water under Radio-Frequency Electromagnetic Waves

Electromagnetic waves, such as microwaves, have been used to enhance various chemical reactions over polyoxometalates. The dielectric properties of catalysts are among the relevant parameters facilitating catalytic reactions under electromagnetic radiation. This study describes the dielectric properties of polyoxometalate catalysts in aqueous and organic solutions to understand the mechanism of interactions between polyoxometalates and electromagnetic waves. Specific loss factors of polyoxometalates were observed at lower frequencies (<1 GHz) by the ionic conduction of the polyoxometalate solution. The evolution of ionic conduction depended strongly on cations rather than anions. Proton-type polyoxometalates exhibited significantly higher loss factors than other cations did. The activation energy for ionic conduction in protonated silicotungstic acid (H₄SiW₁₂O₄₀) was significantly low in water (7.6–14.1 kJ/mol); therefore, the high loss factor of protonated polyoxometalates in water was attributed to the proton relay mechanism (i.e., Grotthuss mechanism). The results suggested that the proton relay mechanism at the radio-frequency band is critical for generating selective interactions of polyoxometalates with applied electromagnetic fields.

Microbial lipid production by Cryptococcus curvatus from vegetable waste hydrolysate

This study primarily evaluated the effect of pre-treatment on release of reducing sugars (RS) from vegetable waste (VW). Different acids and alkalis viz., H₂SO₄, HCl, HNO₃, H₃PO₄, NaOH and KOH were evaluated at varied concentration (0.5, 1.0, 1.5 and 2.0%) for pretreatment. The highest RS yield of 472.36 ± 1.89 g/l and 439.13 ± 1.04 g/l was obtained with 1.5% H₂SO₄ and 2% HCl respectively. Secondly, pre-treated vegetable waste hydrolysates (PT-VWH) were evaluated for yeast fermentation using Cryptococcus curvatus MTCC 2698 for lipid production. Maximum biomass (9.46 ± 0.1 g/l and 8.12 ± 0.1 g/l) and lipid (28.3 ± 0.5% and 26 ± 0.5%) was obtained with 1.5% H₂SO₄ PT-VWH and 2% HCl PT-VWH respectively. The FAME profiling revealed the predominance of palmitic, stearic, oleic and linoleic acid. The presence of these fatty acids in majority has beneficial effect on the biodiesel quality.

Bioethanol production from Ficus religiosa leaves using microwave irradiation

A microwave assisted feasible process for the production of bioethanol from Ficus religiosa leaves was developed. Under the process conditions (8 min. microwave irradiation, 1 M HCl), 10.1 wt% glucose yield was obtained from the leaves. Microwave based hydrolysis process yielded higher glucose content (10.1 wt%) compared to the conventional hydrothermal process (4.1 wt%). Upon fermentation of the hydrolysate using Baker's yeast, 3 wt% (dry wt. basis) of bioethanol was produced.