Abstract: The present disclosure discloses ?-carrageenase mutant OUC-CglA-DPQQ, which has an amino acid sequence as set forth in SEQ ID NO. 1 and an encoding gene as set forth in SEQ ID NO. 2. The ?-carrageenase mutant OUC-CglA-DPQQ is applied to degradation of carrageenan/preparation of ?-carrageenan oligosaccharides with high polymerization degree. The present disclosure further discloses a method for degrading carrageenan/preparing ?-carrageenan oligosaccharides with high polymerization degree by using the ?-carrageenase mutant OUC-CglA-DPQQ. The ?-carrageenase mutant OUC-CglA-DPQQ of the present disclosure can act on low viscosity carrageenan, and the polymerization degree of final product ?-carrageenan oligosaccharides is 10-20. The ?-carrageenase mutant of the present disclosure is excellent in enzymatic properties and specificity, and has important industrial application value and economic value in the preparation of ?-carrageenan oligosaccharides via an enzyme method.

Abstract: A method for enriching niobium and titanium in a mineral containing iron, niobium, and titanium, includes: reacting raw materials comprising 1 part by weight of a mineral containing iron, niobium, and titanium, 0.1-0.8 part by weight of a nickel-containing substance and 0.2-1 part by weight of carbon at 800-1500° C. to obtain a nickel-iron alloy and a niobium-titanium rich slag, where an amount of the mineral containing iron, niobium, and titanium is counted in terms of iron element, and an amount of the nickel-containing substance is counted in terms of nickel element. The nickel-containing substance is one or more selected from the group consisting of oxides of nickel and nickel minerals.