**4. Conclusions**

In the present study, the PL9 pectate lyase PpPel9a was cloned from *P. polymyxa* KF-1 and was used to degrade pectins from different plants. Recombinant PpPel9a was used to degrade citrus pectin, reproducibly yielding the fraction MCP-0.3 that exhibited good prebiotic effects in vitro. This enzyme may be a valuable candidate for preparation of low-molecular-weight pectin fractions.

**Supplementary Materials:** Supplementary materials can be found at http://www.mdpi.com/1422-0067/20/12/ 3060/s1.

**Author Contributions:** Conceptualization, Y.Y. and J.G.; methodology, Y.Y., X.-Y.Z. and H.Z.; software, Y.Z.; writing—original draft preparation, J.G.; writing—review and editing, J.G.; supervision, Y.-F.Z.; project administration, J.G.; funding acquisition, Y.-F.Z.

**Funding:** This research was supported by the Fundamental Research Funds for the Central Universities (2412019QD011), Natural Science Foundation of Jilin Province (20190201258JC).

**Conflicts of Interest:** The authors declare no conflict of interest.
