Synthesis of Ca–Fe‑based heterogeneous catalyst from waste shells and their application for transesterification of Jatropha oil

The depletion of fossil fuel reserves with increased fuel demand and global emissions has increased the search for eco-friendly renewable fuels with a low environmental impact.Biodiesel can be considered as mono-alkyl esters of long-chain fatty acids obtained from the transesterification of vegetable oils and animal fats.Economically low-cost biodiesel production has received considerable interest for blending with fossil-based diesel for a more sustainable future.Therefore,the current study focuses on synthesizing an efficient,low-cost heterogeneous CaO catalyst from waste egg and seashell using a solid-state method and applying it to the transesterification of Jatropha oil.The Ca_(2)Fe_(2)O_(5) solid catalyst was prepared by doping calcined CaO with iron in a 2:1 ratio using ferric oxide(Fe_(2)O_(3)).Furthermore,the catalyst was extruded and analytically char-acterized using XRD,FT IR,BET,and its basic strength was quantified by Hammett indicators.Later on,transesterification of Jatropha oil was optimized by varying reaction parameters,such as the molar ratio of methanol to Jatropha oil,reaction time,and catalyst loading.The maximum conversion yield was 96.3%at a 20:1 methanol-to-oil ratio and 80 bar N_(2) pressure using 5%(w/w)catalyst loading.Furthermore,the catalytic recycling study demonstrated that the Ca_(2)Fe_(2)O_(5) catalyst could retain>70–80%of transesterification efficiency and stability up to 4 cycles under high acid value and moisture conditions.

Recent biotechnological trends in lactic acid bacterial fermentation for food processing industries

Lactic acid bacteria(LAB)are non-mobile,gram-positive,non-spore-forming,micro-aerophilic microorganisms widely explored as starter cultures food industry to enhance the gustatory,nutritional value,imparts appetizing favour,texture to milk,vegetative,meat foods and prolongs their shelf life.This vast review emphasis various LABs widely explored in the food industry.Herein,we have summarized the classifcation of LAB strains,their metabolic pathways for biosynthesis of lactic acid,ethanol,acetic acid and demonstrated their application in various food industries for making fermented milk(yoghurt),cheese,beverages,bread,and animal foods.The wide spectrum of LAB-based probiotics,bacteriocins,exopolysaccharides,bio preservative and their relevant benefts towards human health has also been discussed.Moreover,LAB bacteriocins and probiotics in food application may limit the growth of pathogenic,while boosting health immunity.Microbial exopolysaccharides have interesting characteristics for the fermented food industry as new functional foods.Later on,we have discussed the various advancement in metabolic engineering,synthetic biology tools,which have gained considerable interest to elucidate the biosynthetic pathway for tailoring cellular metabolism for high activity.

Bioelectrochemical system-mediated waste valorization

Bioelectrochemical systems(BESs)are a new and emerging technology in the field of fermentation technology.Electrical energy was provided externally to the microbial electrolysis cells(MECs)to generate hydrogen or value-added chemicals,including caustic,formic acid,acetic acid,and peroxide.Also,BES was designed to recover nutrients,metals or remove recalcitrant compounds.The variety of naturally existing microorganisms and enzymes act as a biocatalyst to induce poten-tial differences amid the electrodes.BESs can be performed with non-catalyzed electrodes(both anode and cathode)under favorable circumstances,unlike conventional fuel cells.In recent years,value-added chemical producing microbial electrosyn-thesis(MES)technology has intensely broadened the prospect for BES.An additional strategy includes the introduction of innovative technologies that help with the manufacturing of alternative materials for electrode preparation,ion-exchange membranes,and pioneering designs.Because of this,BES is emerging as a promising technology.This article deliberates recent signs of progress in BESs so far,focusing on their diverse applications beyond electricity generation and resulting performance.