Utilization of Sweet Potato Starch for Producing Biocomposite Semiconductor Materials

Starch is one of the most promising natural polymers source However, the properties of starch-based materials are not satisfactory. because it is an adsorbent, universally available and low cost. This weakness can be overcome by adding other materials to form biocomposite. Biocomposite is a composite material of a natural polymer （organic phase） and reinforcement/filler （inorganic phase）. The use of filler material that has the properties of semiconductor will produce composite that have semiconducting properties as well. In this research, biocomposite was cast using ZnO as filler in the matrix of sweet potato starch plasticised by glycerol. From the results of XRD （X-ray diffraction） and SEM （scanning electron microscope） analysis showed that ZnO has been dispersed in the matrix and the results of FT-IR was found that sweet potato starch, glycerol, and ZnO are united to form biocomposite. From the test results of mechanical, physical and electrical properties were found that the addition of ZnO concentration of 1%, 3% and 6% lead to improvement of tensile strength from 24.68 kgf/cm2 to 34.43 kgffcm2, decrease in elongation from 26.96% to 8.5%, decrease in water vapour transmission rate from 8.6270 gr·m^2·h^-1 to 4.581 gr·m^2·h^-1, increase in UV absorbance, and conductivity of 5.864 × 10^-7 S/cm. Addition of glycerol concentration of 15%, 25% and 35% wt causes an increase in elongation from 8.75% to 33.04%, and decrease in tensile strength from 54.57% to 14.64%.

Effects of Bacillus amyloliquefaciens Biofertilizer on Brassica juncea var. multiceps Growth and N_2O Emission from Soil

In this study, Bacil us amyloliquefaciens A3 was continual y incubated in shake fIasks contalning wastewater from sweet potato starch production as an ef-fective biofertiIizer for cuItivation of Brassica juncea var. multiceps（XueIihong）. Based on pot experiments in the greenhouse, the effects of chemical fertiIizers （CN）, biofertiIizer （BF）, inactivated broth （BI）, starch wastewater （SW） and the combination of biofertiIizer and chemical fertiIizer （BC） on the yield, NO3- content and NO2- con-tent of XueIihong, soiI physicochemical properties and N2O emission were investi-gated. The resuIts showed that the yield of XueIihong in BC and CN treatments was improved by five times compared with CK; BF and SW treatments had insignifi-cant impact on the yield of XueIihong. Compared with CN treatment, BCL treatment exhibited simiIar improving effects on the yield of XueIihong, in which NO3- content of XueIihong and soiI was reduced by 16.4%-73.6% and 22%-29%, which reduced the risk of nitrogen eIuviations in soiI; average N2O fIux （FPV30） in BCL treatment was reduced by 58.3%-73.1% compared with CN treatment. In concIusion, B. amy-loliquefaciens is a feasibIe Iow-cost biofertiIizer for sustalnabIe vegetabIe farming with a great potential for starch wastewater utiIization.

Effects of Bacillus amyloliquefaciens Biofertilizer on Tea Yield and Quality

[Objective] This study was aimed to explore the effects of Bacil us amy-loliquefaciens biofertilizer on tea yield and quality. [Method] The field plot experiment was conducted with the biofertilizer treatments and control to investigate 100-bud weight and main biochemical components. [Result] The treatments by Bacil us amy-loliquefaciens biofertilizer, which was fermented using sweet potato starch wastewa-ter （SPSW） as culture medium, improved 100-bud weight and tea quality significant-ly under the concentration of 0.8×108, 1.6×108 and 3.2×108 cfu/ml with the dose of 1 L/m2 for 4 times. At the optimum concentration of 1.6 ×108 cfu/ml, the biofertilizer treatment increased the 100-bud weight by 22.3%, water extracting materials by 21.9%, amino acids content by 8.83%, tea polyphenol content by 9.76%, and de-creased theine content by 8.32%, respectively. Compared with the control, there was no significant difference between the SPSW treatment and the control. [Con-clusion] The production of the B. amyloliquefaciens biofertilizer could consume SP-SW, and the application of the biofertilizer could improved the tea yield and quality, which provided references for the development of ecological agriculture.

The granule characteristics of yam,sweet potato and tapioca starches determined by gravitational field-flow fractionation

To study the characteristics of tuber starchgranules,firstly,three kinds of common tuber starches were separated and characterized by gravitational field-flow fractionation(GrFFF)instrument,and the ratios of large and small starch granules A/B were calculated.Then,the liquid of peak A and peak B was collected and observed by scanning electron microscope(SEM)to verify the separation result of GrFFF.Secondly,the particle size distribution and crystal characteristics were characterized by particle size analyser,X-ray diffraction(X-ray)and fourier transform infrared spectroscopy(FT-IR).Three kinds of tuber starches all had the bimodal distribution in GrFFF.Peak A contained large particles,and peak B contained small particles.For yam starch,the ratio of starch granules A/B was much higher than 1;for sweet potato starch the ratio was approximately equal to 1;for tapioca starch,the ratio was much lower than 1.Moreover,the starch granules of sweet potato and tapioca were both A-type crystallinity,while yam starch granules were C-type crystallinity.GrFFF could be used to characterize and separate large and small granules of tuber starches and estimate the ratio of starch granules A/B.Yam starch was suitable for the development of slowly digestible starch(one kind of functional food),which could delay the occurrence of metabolic syndrome,diabetes and cardiovascular diseases.Tapioca starch was suitable for plant capsules,which were safer than gelatin capsule and could prevent the"poison capsule"incident from happening.