Abstract: An anaerobic-AO-SACR combined advanced nitrogen removal system for high ammonia-nitrogen wastewater, in which high ammonia-nitrogen wastewater first enters an anaerobic reactor to remove most of organic matters from the wastewater, effluent water enters an AO reactor for nitrogen removal by pre-denitrification in an anoxic zone and for removal of the remaining organic matters and nitrification of ammonia nitrogen in an aerobic zone, and then the effluent water enters an intermediate pool. Meanwhile, under the control of a water quality testing device and a PLC controller, a part of raw water is introduced into the intermediate pool to adjust the carbon nitrogen ratio of the wastewater.

Abstract: The present invention provides a mutant with enhanced secretion of L-asparaginase and its application, which relates to the field of enzyme engineering. This invention successfully constructed a mutant with enhanced secretion of L-asparaginase through N-terminal deletion on amino acid sequence of L-asparaginase, and then expressed the mutant via a recombinant strain. Compared with the wild L-asparaginase, the secretion ability of L-asparaginase mutant in present invention significantly improves by 3.14 times compared to that of wild type. The recombinant strain that constructed in this prevention has an L-asparaginase yield of 407.6 U/mL and a production efficiency of 9.26 U/(mL/h), which reaches to the highest yield been reported.

Abstract: The present invention provides a mutant with enhanced secretion of L-asparaginase and its application, which relates to the field of enzyme engineering. This invention successfully constructed a mutant with enhanced secretion of L-asparaginase through N-terminal deletion on amino acid sequence of L-asparaginase, and then expressed the mutant via a recombinant strain. Compared with the wild L-asparaginase, the secretion ability of L-asparaginase mutant in present invention significantly improves by 3.14 times compared to that of wild type. The recombinant strain that constructed in this prevention has an L-asparaginase yield of 407.6 U/mL and a production efficiency of 9.26 U/(mL/h), which reaches to the highest yield been reported.