The present disclosure provides compositions including enzyme loaded biologically derived microspheres capable of self-degradation upon rehydration. The present disclosure also provides methods of making the enzyme loaded biologically derived microspheres. The present disclosure also provides methods of using the disclosed microspheres to induce an embolism in a subject as well as methods of using the disclosed microspheres to treat a disease or disorder in a subject.

Disclosed is an auto-induction regulatory system based on quorum sensing, comprising luxI, luxR and egfp, wherein, the promoter for controlling the expression of luxI and luxR is selected from P.sub.luxI, P.sub.BB or P.sub.J23100; the promoter for controlling the expression of egfp is selected from P.sub.luxI, P.sub.luxI(T-38C) or P.sub.luxI(C-77T). Also disclosed are an application of the auto-induction regulatory system based on quorum sensing in the automatic regulation of expression of a target gene of engineered Escherichia coli, as well as an application thereof in the preparation of alginate lyase and esterase. Further disclosed are a recombinant expression vector and a recombinant engineered bacterium comprising the auto-induction regulatory system based on quorum sensing.