Improved extraction and purification of the hydrophobin HFBI

Abstract

Hydrophobins (HFBs) are a group of highly functional, low molecular weight proteins with the ability to self‐assemble at hydrophobic‐hydrophilic interfaces. The surface active, cysteine‐rich proteins are found in filamentous fungi such as Trichoderma reesei. In the present study multiple extraction solvents and conditions were screened for the mycelium bound hydrophobin HFBI and the effects on the total amount of extracted proteins, HFBI recovery and HFBI gushing activity were investigated to gain a more thorough scientific insight on the extraction efficiency and selectivity. Results indicated the enhanced selectivity for HFBI extraction from the fungal biomass using 60% ethanol compared to solutions containing 1% sodium dodecyl sulphate (SDS). Complementing the higher selectivity, HFBI recovery was increased from 6.9 ± 0.6 mg HFBI (1% SDS) to 9.4 ± 0.4 mg HFBI per gram dry fungal biomass for extracts containing 60% ethanol. Furthermore, subsequent to HPLC purification, Cold Induced Phase Separation (CIPS) of acetonitrile‐water systems was investigated at different pH levels. CIPS at pH 2.0 was found to effectively remove the majority of sorbicillinoid pigments from the purified HFBI fraction. The improved method resulted in a recovery of 85.4% of the extracted HFBI after final purification.

Identification and Functional Analysis of a Novel Hydrophobic Protein VdHP1 from Verticillium dahliae

“…It was reported that MPG1 , as a hydrophobin gene, affected the virulence, conidiation, and appressorium formation in Magnaporthe grisea ( 28 ). In addition, HFB4 and HFB10 could affect the spore-mediated diffusion process; they encapsulated spores and mediated environmental interactions ( 29 ). Two hydrophobic genes ( Pgh1 and Pgh2 ) were associated with the growth and development of Phlebiopsis gigantea ( 30 ).…”

“You Are What You Eat”: How Fungal Adaptation Can Be Leveraged toward Myco‐Material Properties

“…As an example, improved flame retardancy properties and thermally stable carbonaceous structures were obtained through the hydrophobin surface treatment of cotton fabrics, as the protein coating favored cellulose dehydration over its depolymerization. [ 106 ] Thus, the possibility to engineer strains that secrete more hydrophobins may be highly interesting, however we note that the isolation of purified hydrophobins generally involves many steps and harsh solvents, all for a rather low yield, [ 107 ] and is therefore perhaps unsuited for large‐scale commercial applications.…”