Etherification of Alkali-pretreated Sugarcane Bagasse Cellulose in Tetrahydrofuran

Sugarcane bagasse(SCB)is an important by-product in the sugar industry.It is a source of cellulose fibers or cellulose for paper mills and textiles factories.In this study,SCB was ethyl etherified in tetrahydrofuran(THF)after alkali pretreatment.The alkali concentration for the pretreatment,the ratio of ethyl bromide(EtBr)to dried SCB in the reaction,reaction time,and temperature were investigated for the etherification of SCB.The ethoxyl content and characterization of the product were determined using headspace gas chromatography(HS-GC),Fourier Transform Infrared(FT-IR)and 13C-NMR spectroscopy,respectively.It was found that SCB was well-etherified with EtBr in alkali-THF.Upon ethylation of SCB,the ethoxyl content of the product was high when the alkali concentration and the ratio of EtBr to dried SCB were controlled from 50%to 75%and 4:1(V/w)to 6:1(V/w),respectively.The reaction occurred optimally when the temperature was controlled below 110℃;above this temperature,the degree of etherification decreased.The thermal stability of ethylated SCB was higher than that of SCB but slightly lower than that of commercial ethyl cellulose.Ethylated SCB has the potential to form composites with many materials because it is soluble in a wide variety of solvents.

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.

Adhesion and corrosion resistance of polycaprolactone coating on NiTi alloy surface after alkali heat pretreatment

Selective laser melting of nickel-titanium alloy(SLM-NiTi)can precisely control the size of the sample molding structure and has attracted extensive attention due to its special superelasticity and shape memory effect.However,the biological inertness and poor corrosion resistance of SLM-NiTi alloy limit their wide application as biomedical implant materials.In this study,polycaprolactone(PCL)coating was prepared on SLM-NiTi alloy by dipping and pulling method,and the effects of alkali heat pretreatment on the morphology,adhesion,corrosion resistance,long-term stability and biomineralisation of the PCL coatings were investigated.The results showed that PCL coating can substan-tially improve the performance of SLM-NiTi alloy,and the PCL coating after alkali heat pretreatment has higher adhesion(increased from 1,747 to 2,498 mN)and lower corrosion current density(reduced by about an order of magnitude compared to PCL coating alone).In addition,the necessary stability,biomineralisation and biocompatibility ability of coatings were also further improved.Therefore,the alkali heat pretreated PCL-coated SLM-NiTi alloy has good application prospects in implants due to its superior properties.