Enhanced proteolytic activities of Geotrichum candidum and Penicillium camembertii in mixed culture

Diauxic growth of Geotrichum candidum and Penicillium camembertii on amino acids and glucose

“…candidum and P. camembertii species exhibited diauxic behaviour when growing on some amino acids and glucose. However, no stationary phase, namely a period of time with constant cell concentration, was observed between the two growth phases during P. camembertii culture, in agreement with the continuous proteolysis and assimilation of peptides by P. camembertii (Boutrou et al, 2006); in contrast, a clear glucose repression was observed during G. candidum growth on glucose and a single amino acid, shown to be an energy-saving response (Ronne, 1995), leading to a stationary phase after glucose exhaustion from the medium and before the second growth phase with the considered amino acid as both carbon and nitrogen source. Even if glucose is not a relevant carbon source in terms of food microbiology, a clear physiological difference was highlighted regarding the assimilation of some amino acids by the two fungi, which are involved in association in the ripening of soft Camembert cheeses.…”

“…It should also be related to the earlier colonization of the surface of white soft cheese by G. candidum, which develops from the first days of ripening, while P. camembertii growth starts later, during the second week of ripening Boutrou et al, 2006). Indeed, previous experiments on Camembert juice showed that G. candidum immediately degraded large and medium peptides into free amino acids, while P. camembertii assimilated large peptides, but medium and small peptides were less consumed (Boutrou et al, 2006).…”

Competition during submerged mixed culture of Geotrichum candidum and Penicillium camembertii on glucose and threonine

“…With this aim, lactate, available for the secondary cheese ripening microflora, and a major amino acid, glutamate, previously shown to be a convenient carbon and nitrogen sources for G. candidum and P. camembertii (Plihon et al, 1998), were chosen . The mixed culture improved rates of growth and metabolite production; however, and as also observed on cheese juice (Boutrou et al, 2006), the behavior recorded was similar to that observed during G. candidum pure culture . In particular the absence of lactate assimilation during growth, illustrating the commensalism between the two species.…”

“…The enzymatic activities of G. candidum allowed an easier assimilation of peptides and amino acids as carbon sources by P. camembertii ; no other carbon sources were needed, or used only at the end of culture for cell maintenance (Aziza et al, 2005). Investigation of the proteolytic activities involved in the synergistic effects between the two fungi showed that these effects are predominant during the second part of culture (Boutrou et al, 2006). Indeed, a low assimilation of medium and small peptides was shown during the first part of a mixed culture on cheese juice.…”

Response Surface Methodology Modelling of an Aqueous Two-Phase System for Purification of Protease from Penicillium candidum (PCA 1/TT031) under Solid State Fermentation and Its Biochemical Characterization

“…P. camemberti produce two extracellular proteinases [5]: a neutral proteinase and an acid proteinase [6,7,8,9]. P. camemberti also synthesis exopeptidases [10]: an exocellular acid carboxypeptidase [11,12], a neutral carboxypeptidase which is mycelial bound [12], and an exocellular aminopeptidase owing to two components [8,13,14,15]. Neutral proteases are significant in the dairy industry since they influence a specific function in hydrolyzing hydrophobic amino acid bonds at a neutral pH, so they reduce the bitterness of food protein hydrolysates [16].…”