Overexpression of native PSE1 and SOD1 in Saccharomyces cerevisiae improved heterologous cellulase secretion

Expression of Fungal Hydrolases in Saccharomyces cerevisiae

“…The potential of "-omics" data and other postgenomic technologies to identify possible gene candidates or pathways to be used in strain engineering strategies is clearly illustrated by the transcriptomics-based work of Gasser et al 104 The advantages of identifying secretion-enhancing genes and overexpressing them individually or in combination were eloquently demonstrated by Kroukamp et al 105 In this study, the authors demonstrated a synergetic 4.5-fold increase in Saccharomycopsis fibuligera BGL1 production with the overexpression of native S. cerevisiae PSE1 and SOD1. A limited number of industrial strains for the bioconversion of lignocellulosics are currently available.…”

Rational design and evolutional fine tuning of Saccharomyces cerevisiae for biomass breakdown

“…Different heterologous proteins exert varying degrees of stress on host cells, which may result in the generation of reactive oxygen species (ROS). Simultaneous overexpression of sod1 (encoding a superoxide dismutase involved in ROS detoxification) and pse1 results in a 4.5-fold increase in the activity of secreted BGL [26]. Thus, the secretion of heterologous proteins in yeast is subjected to several bottlenecks resulting in supoptimal yields.…”

“…-fold increase in the activity of heterologous cellulases, Saccharomycopsis fibuligera Cel3A [BGL] and Neocallimastix patriciarum Cel6A [exoglucanase], respectively, with increase in their secretion by S. cerevisiae[26]. Overexpression of Pdi1, which encodes protein disulfide isomerase, an endoplasmic reticulum (ER)-resident protein that both forms disulfide bonds and exhibits chaperone function, increases the activity of Trichoderma reesei Cel7A [CBH] by 62%, compared with reference strain[27].…”

Heterologous expression of cellulase genes in natural Saccharomyces cerevisiae strains

“…Although these approaches have been successfully applied to enhance secreted levels of a variety of different reporter proteins, a wide range in secreted protein titers were observed (24,(41)(42)(43)(44). The secretion enhancing abilities of many strains vary depending on the specific reporter protein characteristics and the properties of the host strain that may influence the protein's transit through the secretion pathway (20,24,(45)(46)(47).…”

“…Pre-treatment is necessary, but increases the overall process costs (43,44). The pre-treatment itself solubilises little glucose and generally solubilises hemi-celluloses, although it depends on the pre-treatment method (45). Types of pre-treatments currently used include ammonia fiber explosion, chemical treatment, biological treatment, and steam explosion (39).…”