Zhengzhong Zhou

Starch sugars are widely used in various fields, and precise control of their molecular weight may further enhance their application value. This study developed a controllable pore‐size enzyme membrane reactor (EMR) to produce starch sugars with target molecular weight. Firstly, polyimide membranes were modified with multiamino compounds to create active sites for subsequent enzyme immobilization. The sieving performance of these modified membranes was analyzed using polyethylene glycol (PEG) of different molecular weights. Next, glutaraldehyde was grafted onto the membrane surface to provide active sites for starch enzyme immobilization. By adjusting the pore size of the EMR, controlled production of starch sugars with specific molecular weights was achieved. Finally, the effects of different operating pressures and flow rates on the sugar production efficiency of the EMR were investigated. This study not only provides guidance for the controlled production of starch sugars but also offers insights into the controllable preparation of EMRs.

Bioethanol, as a renewable energy source, has been widely used in the energy sector, particularly in replacing traditional petroleum energy, and holds great potential. This study involves a whole life cycle assessment of bioethanol production and the co-production of high-value by-products—xylose, lignin, and steam—using three types of waste biomass: corn cobs, corn straw, and wheat straw as feedstocks by chopping, pretreatment, hydrolysis, fermentation, and distillation methods. Secondly, the benefits of three raw materials are compared for preparing bioethanol, and their impact on the environment and energy production is analyzed. The comparison indicates that corn cobs offer the best overall benefits, with a net energy balance (NEB) of 6902 MJ/Mg of ethanol and a net energy ratio (NER) of 1.30. The global warming potential (GWP) is 1.75 × 10⁻², acidification potential (AP) is 1.02 × 10⁻², eutrophication potential (EP) is 2.63 × 10⁻⁴, photochemical ozone creation potential (POCP) is 3.19 × 10⁻⁸, and human toxicity potential (HTP) is 1.52 × 10⁻⁴. This paper can provide a theoretical reference and data supporting the green refining of bioethanol and the high-value utilization of by-products, and broaden its application prospects.