Loosenin-Like Proteins from Phanerochaete carnosa Impact Both Cellulose and Chitin Fiber Networks

Mareike Monschein, Eleni Ioannou, Taru Koitto, Leamon A. K. M. AI Amin, Jutta J. Varis, Edward R. Wagner, Kirsi S. Mikkonen, Daniel J. Cosgrove, Emma R. Master*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

7 Downloads (Pure)


Microbial expansin-related proteins are ubiquitous across bacterial and fungal organisms and reportedly play a role in the modification and deconstruction of cell wall polysaccharides, including lignocellulose. So far, very few microbial expansin-related proteins, including loosenins and loosenin-like (LOOL) proteins, have been functionally characterized. Herein, four LOOLs encoded by Phanerochaete carnosa and belonging to different subfamilies (i.e., PcaLOOL7 and PcaLOOL9 from subfamily A and PcaLOOL2 and PcaLOOL12 from subfamily B) were recombinantly produced and the purified proteins were characterized using diverse cellulose and chitin substrates. The purified PcaLOOLs weakened cellulose filter paper and cellulose nanofibril networks (CNF); however, none significantly boosted cellulase activity on the selected cellulose substrates (Avicel and Whatman paper). Although fusing the family 63 carbohydrate-binding module (CBM63) of BsEXLX1 encoded by Bacillus subtilis to PcaLOOLs increased their binding to cellulose, the CBM63 fusion appeared to reduce the cellulose filter paper weakening observed using wild-type proteins. Binding of PcaLOOLs to alpha-chitin was considerably higher than that to cellulose (Avicel) and was pH dependent, with the highest binding at pH 5.0. Amendment of certain PcaLOOLs in fungal liquid cultivations also impacted the density of the cultivated mycelia. The present study reveals the potential of fungal expansin-related proteins to impact both cellulose and chitin networks and points to a possible biological role in fungal cell wall processing.

Original languageEnglish
Number of pages15
JournalApplied and Environmental Microbiology
Issue number1
Publication statusPublished - Jan 2023
MoE publication typeA1 Journal article-refereed


  • biotechnology
  • carbohydrate active enzymes
  • carbohydrate binding
  • cellulose
  • chitin
  • expansin
  • filamentous fungi
  • lignocellulose
  • loosenin
  • Phanerochaete carnosa


Dive into the research topics of 'Loosenin-Like Proteins from Phanerochaete carnosa Impact Both Cellulose and Chitin Fiber Networks'. Together they form a unique fingerprint.

    Master, E., Dahiya, D., Pohto, A., Sidorova, L. & Ioannou, E.


    Project: EU: Framework programmes funding


    Master, E., Dahiya, D., Leamon, A. K. M. A. A., Pohto, A. & Ioannou, E.


    Project: Other external funding: Other foreign funding


    Mollerup, F., Jurak, E., Aumala, V., Master, E., Karppi, J., Virtanen, S., Littunen, K., Mai-Gisondi, G., Monschein, M., Pohto, A., Dahiya, D. & Leamon, A. K. M. A. A.


    Project: EU: ERC grants

Cite this