Hydrophobins and chaplins: Novel bio-surfactants for food dispersions a review

Fungal biosurfactants, from nature to biotechnological product: bioprospection, production and potential applications

“…Hydrophobins are globular proteins, with low molecular weight (< 20 kDa) and primary sequence of about 100–150 amino acids and have 8 cysteine residues that form 4 intramolecular disulfide bonds, stabilizing their tertiary structure and promoting surfactant and emulsifying activity [ 137 , 138 ]. Hydrophobins are classified into two classes (I and II) according to their assembly characteristics at hydrophobic–hydrophilic interfaces, solubility and hydropathy.…”

“…Class I hydrophobins form structures similar to amyloid fibrils, termed rodlet layers with a β-sheet conformation and are soluble only in strong acids, on the other hand, class II hydrophobins form regular crystalline structures with a random spiral conformation and can be easily dissolved with organic solvents or detergents [ 139 , 140 ]. Some of these proteins may exhibit glycosylation [ 137 , 139 ]. Although some hydrophobins can form oligomers as a strategy to increase their solubility in solution, others remain monomeric even at high concentrations [ 13 , 141 ].…”

“…Class I hydrophobins were isolated from Schizophyllum commune (SC3) and class II hydrophobins from Trichoderma reesei (HFBI and HFBII) [ 138 , 139 ], as well as, several ascomycetes and basidiomycetes capable of secreting hydrophobins in their cell wall, which has an ecological role related to local environment modification [ 13 , 137 ]. It is believed that these hydrophobins assist hyphae to grow from a liquid phase into air by covering the surface of aerial hyphae with a hydrophobic layer.…”

“…It is believed that these hydrophobins assist hyphae to grow from a liquid phase into air by covering the surface of aerial hyphae with a hydrophobic layer. Likewise, spore dispersal, adhesion, pathogenesis, and breaking surface tension have been linked to hydrophobins [ 13 , 137 ]. From a biotechnological perspective, due to their high surface activity and non-immunogenicity, hydrophobins have a versatility of applications as agents for solubilization and delivery of hydrophobic drugs, emulsifying agents for food, protein purification tags, tools for protein and cell immobilization, coatings for biomaterials, biosensors and, biomineralization templates [ 137 , 140 , 142 ].…”

“…Likewise, spore dispersal, adhesion, pathogenesis, and breaking surface tension have been linked to hydrophobins [ 13 , 137 ]. From a biotechnological perspective, due to their high surface activity and non-immunogenicity, hydrophobins have a versatility of applications as agents for solubilization and delivery of hydrophobic drugs, emulsifying agents for food, protein purification tags, tools for protein and cell immobilization, coatings for biomaterials, biosensors and, biomineralization templates [ 137 , 140 , 142 ]. Although there is a growing potential to manipulate hydrophobin variants for specific applications by protein engineering and heterologous expression in host cells, the insertion of these molecules into commercial applications is still limited due to low productivity, the need for additional steps for recovery and post-transcriptional modifications of the surfactant protein [ 137 , 140 ].…”