Green synthesis of biocompatible Gd^(3+)-doped ultrasmall carbon-based nanohybrids from coffee wastes

A cheap method allowing fabrication of biocompatible,ultra-small(2-10 nm)and fluorescent(λ_(em)=425-500 nm)nanohybrids(NHs)from coffee wastes is reported.The gadolinium-doped nanohybrids(GDNHs)or gadolinium-free carbon dots(GFCDs)can be synthesized in a domestic microwave oven according to green synthesis principles.Hydrodynamic sizes,chemical composition,impact on proton magnetic resonance relaxation time and optical properties of the GDNHs and GFCDs were studied in details and compared.In particular,doping of the NHs with Gd^(3+)ions,up to 1.87%w/w of gadolinium per particles’weight,will allow their application for magnetic resonance imaging(MRI).Furthermore,cell culture tests on human adenocarcinomic alveolar basal epithelial cells line(A549)have shown high biocompatibility of the GDNHs and in a wide concentration range 100-1000μg/ml.

Lactic Acid Fermentation from Coffee Ground Waste Hydrolysate by Lactobacillus rhamnosus

Lactic acid is an important organic acid that is widely used in the food,pharmaceutical,and cosmetic industries.Lactic acid was produced from coffee ground waste which contains fermentable sugars and is increasingly generated from our daily dietary life.Among 114 strains of Lactobacillus species,Lactobacillus rhamnosus ATCC 10863 was selected for the production of lactic acid from coffee ground waste.Through alkali pretreatment and saccharification,cellulose and hemicellulose in coffee ground waste were converted into fermentable sugars.Pretreatment experiments were conducted at various alkali solution,concentrations,and times.Alkali pretreatment with 35 g/L of KOH at 121oC for 60 min,the highest concentration of fermentable sugars was produced.The optimum concentration of Viscozyme L was 2%when saccharification was proceeded at 55oC for 7 days.The productivity of lactic acid fermentation was the highest(0.59 g/L/h)at 100 g of coffee ground waste(1x concentration),whereas the lactic acid concentration was the highest at 600 g of coffee ground waste(6x concentration).As the concentration of coffee ground increased,the lactic acid concentration was also increased,however,the amount was not proportional to the coffee ground waste used.In this study,it was found that coffee ground waste could be used as a culture medium for Lactobacillus rhamnosus ATCC 10863 through pretreatment and saccharification for the production of lactic acid.

From food waste to high-capacity hard carbon for rechargeable sodium-ion batteries

In this study,we introduce a straightforward and effective approach to produce P-doped hard carbon using coffee grounds as the precursor,with H_(3)PO_(4)serving as the doping agent.By varying the concentrations of H_(3)PO_(4)(1 M,2 M,and 3 M),we aimed to determine the optimal doping level for maximizing the incorporation of phosphorus ions into the carbon framework.Our investigation revealed that using 2 M of H_(3)PO_(4)as the dopant material for hard carbon led to promising electrochemical performance when employed as an anode material for sodium-ion batteries.The P-doped hard carbon,carbonized at 1300℃,exhibited an impressive reversible capacity of 341 mAh g1 at a current density of 20 mA g1,with an initial Coulombic efficiency(ICE)of 83%.This outstanding electrochemical performance of P-doped hard carbon can be attributed to its unique properties,including a porous agglomerated structure,a significant interlayer spacing,and the formation of C-P bonds.