Project description:Prior to the introduction of novel food ingredients into the food supply, safety risk assessments are required, and numerous prediction models have been developed and validated to evaluate safety. The allergenic risk potential of Helaina recombinant human lactoferrin (rhLF, Effera™), produced in Komagataella phaffii (K. phaffii) was assessed by literature search, bioinformatics sequence comparisons to known allergens, glycan allergenicity assessment, and a simulated pepsin digestion model. The literature search identified no allergenic risk for Helaina rhLF, K. phaffii, or its glycans. Bioinformatics search strategies showed no significant risk for cross-reactivity or allergenicity between rhLF or the 36 residual host proteins and known human allergens. Helaina rhLF was also rapidly digested in simulated gastric fluid and its digestibility profile was comparable to human milk lactoferrin (hmLF), further demonstrating a low allergenic risk and similarity to the hmLF form. Collectively, these results demonstrate a low allergenic risk potential of Helaina rhLF and do not support the need for further clinical testing or serum IgE binding to evaluate Helaina rhLF for risk of food allergy prior to addition into the food supply.
Project description:The yeast Komagataella phaffii is a promising alternative host for manufacturing of therapeutic proteins. Deletion of unneeded endogenous proteins could increase the secreted titer of recombinant proteins by redirecting cellular resources. Genetic engineering in non-model hosts is hampered by limited annotation of genes, especially essential genes. In this study, we identified the set of endogenous secreted proteins in K. phaffii and attempted to disrupt these genes. We designed, transformed, and sequenced a pooled CRISPR-Cas9 knockout library to determine which genes are essential. With this knowledge, we rapidly disrupted up to 9 consecutive genes in K. phaffii. Engineered strains exhibited a ~20x increase in the production of human serum albumin and a 2x increase in the production of a monoclonal antibody. The pooled CRISPR-Cas9 library and knowledge of gene essentiality reported here will facilitate future efforts to engineer K. phaffii for production of other recombinant therapeutic proteins and enzymes.