Application of multistage induced electric field for acid hydrolysis of starch in a continuous-flow reactor.

Herein, a multistage induced electric field (IEF) combined with a continuous-flow reactor was utilized to assist the acid hydrolysis of corn, potato, and waxy corn starch for avoiding plate corrosion and heavy metal leakage. It was found that adding IEF stages was beneficial to improve the hydrolysis efficiency. Treating potato, corn, and waxy corn starch via continuous-flow IEF increased the reducing sugar contents up to 78.76 %, 57.86 %, and 66.18 %, respectively. The electrical conductivity of starch grew with the reaction stages, while starch yield demonstrated the opposite trend. Treated starch had higher solubility and gelatinization peak temperature than native starch, with the gelatinization enthalpy showing fluctuations. Meanwhile, the swelling power decreased as the number of IEF stages was increased. Observations of Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy indicated that the treated starch became more ordered, and crystalline regions were destroyed to various degrees with pores forming on particle surfaces. These variations could be attributed to acid hydrolysis and IEF.

Production of hydrogen and methane from potatoes by two-phase anaerobic fermentation.

A two-phase anaerobic process to produce hydrogen and methane from potatoes was investigated. In the first phase, hydrogen was produced using heat-shocked sludge. About 12h lag-phase vanished, hydrogen yield increased from 200.4 ml/g-TVS to 217.5 ml/g-TVS and the maximum specific hydrogen production rate also increased from 703.4 ml/g-VSS d to 800.5 ml/g-VSS d when improved substrate was used, in which Cl(-) was substituted for SO(4)(2-). Better performances of 271.2 ml-H(2)/g-TVS and 944.7 ml-H(2)/g-VSS d were achieved when potatoes were pretreated by alpha amylase and glucoamylase. In the second phase, methane was produced from the residual of the first phase using methanogens. The maximum additional methane yield was 157.9 ml/g-TVS and the maximum specific methane production rate was 102.7 ml/g-VSS d. The results showed that the energy efficiency increased from about 20% (hydrogen production process) to about 60%, which indicated the energy efficiency can be improved by combined hydrogen and methane production process.