Correlation of cell growth and heterologous protein production by Saccharomyces cerevisiae

With the increasing demand for biopharmaceutical proteins and industrial enzymes, it is necessary to optimize the production by microbial fermentation or cell cultures. Yeasts are well established for the production of a wide range of recombinant proteins, but there are also some limitations; e.g., metabolic and cellular stresses have a strong impact on recombinant protein production. In this work, we investigated the effect of the specific growth rate on the production of two different recombinant proteins. Our results show that human insulin precursor is produced in a growth-associated manner, whereas alpha-amylase tends to have a higher yield on substrate at low specific growth rates. Based on transcriptional analysis, we found that the difference in the production of the two proteins as function of the specific growth rate is mainly due to differences in endoplasmic reticulum processing, protein turnover, cell cycle, and global stress response. We also found that there is a shift at a specific growth rate of 0.1 h(-1) that influences protein production. Thus, for lower specific growth rates, the alpha-amylase and insulin precursor-producing strains present similar cell responses and phenotypes, whereas for higher specific growth rates, the two strains respond differently to changes in the specific growth rate

Recent advances in Pichia pastoris as host for heterologous expression system for lipases : a review

The production of heterologous lipases is one of the most promising strategies to increase the productivity of the bioprocesses and to reduce costs, with the final objective that more industrial lipase applications could be implemented. In this chapter, an overview of the new success in synthetic biology, with traditional molecular genetic techniques and bioprocess engineering in the last 5 years in the cell factory Pichia pastoris, the most promising host system for heterologous lipase production, is presented. The goals get on heterologous Candida antarctica, Rhizopus oryzae, and Candida rugosa lipases, three of the most common lipases used in biocatalysis, are showed. Finally, new cell factories producing heterologous lipases are presented

Gestione Chirurgica delle IOL dislocate in camera vitrea vitrectomia: e fissazione sclerale.

Struttura Complessa di Oftalmologia, Universita di ModenaObiettivo: valutare l\u2019incidenza di complicanze dell\u2019intervento chirurgico di rimozione della IOL dislocata in camera vitrea e sua sostituzione con una IOL a fissazione sclerale. Materiali e metodi: 18 occhi, che presentavano una dislocazione in camera vitrea della IOL per rottura della capsula posteriore o disinsersione della zonula, sono stati sottoposti a vitrectomia via pars plana ed estrazione della IOL con ausilio di perfluorocarbonato ed a impianto di IOL a fissazione sclerale mediante tecnica di Lewis modificata. I pazienti sono stati sottoposti a misurazione dell\u2019acuita visiva, ad esame oftalmoscopico ed a microscopia endoteliale dopo 1, 3 e 6 mesi dall\u2019intervento. Risultati: intraoperatoriamente si sono verificati 2 casi di sanguinamento vitreale. Le complicanze postoperatorie sono state 2 casi di ipertono (risoltosi con terapia), 4 di edema corneale, 2 casi di edema maculare cistoide e 1 distacco di retina. Conclusioni: la rimozione della IOL dislocata dalla camera vitrea e la sua sostituzione con una IOL a fissazione sclerale con tecnica di Lewis modificata si e dimostrata un intervento chirurgico sicuro considerando la relativa incidenza di gravi complicanze