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Andreprevotia sp. strain IGB-42 is a chitin-degrading bacterium isolated from the soil of an anthill. The genome contains 4.7 Mb, a G+C content of 61.31%, 4,257 predicted open reading frames, and a set of industrially interesting chitinase genes.

People and animals share the same environment and antibiotics are used in both. Thus, antibiotics resistance is a major common issue for human and veterinary medicine. The potential impact of antibiotics use in animals on resistance in humans is frequently the focus of debate. In this paper the transmission pathways of resistant bacteria between animals and humans are described and the question is addressed whether a reduction in antibiotics use in animals contributes to the improvement of the resistance situation in humans. Direct contact between humans and animals, transmission of bacteria via food, and indirect transmission via emissions in the environment and the subsequent exposure of humans via the environment are the major transmission routes to be considered. It can thus be established that the relevance of these various transmission routes varies significantly among bacterial species. Furthermore, despite numerous investigations, the exact significance of transmission pathways and the bacteria transferred for the resistance situation in humans cannot yet be precisely quantified. There is evidence that antibiotics use in animals fosters the spread of resistant organisms in animals. Recent studies also suggest that there might be a relationship between antibiotics use in animals and the occurrence of resistance in humans. However, this relationship is complex, and for a better understanding of it and the role of the various transmission pathways, further collaborative studies between veterinary and medical science are needed.

Objectives: To explore Candida guilliermondii for the production of long-chain dicarboxylic acids (DCA), we performed metabolic pathway engineering aiming to prevent DCA consumption during v-oxidation, but also to increase its production via the o-oxidation pathway. Results: We identified the major v- and o-oxidation pathway genes in C. guilliermondii and performed first steps in the strain improvement. A double pox disruption mutant was created that slowed growth with oleic acid but showed accelerated DCA degradation. Increase in DCA production was achieved by homologous overexpression of a plasmid borne cytochrome P450 monooxygenase gene. Conclusion: C. guilliermondii is a promising biocatalyst for DCA production but further insight into its fatty acid metabolism is necessary.

Synthesis of β-ionone in recombinant Saccharomyces cerevisiae is limited by the efficiency of Carotenoid Cleavage Dioxygenases (CCD), membrane-tethered enzymes catalyzing the last step in the pathway. We performed in silico design and membrane affinity analysis, focused on single-point mutations of PhCCD1 to improve membrane anchoring. The resulting constructs were tested in a β-carotene hyper-producing strain by comparing colony pigmentation against colonies transformed with native PhCCD1 and further analyzed by β-ionone quantification via RP-HPLC. Two single-point mutants increased β-ionone yields almost 3-fold when compared to native PhCCD1. We also aimed to improve substrate accessibility of PhCCD1 through the amino-terminal addition of membrane destination peptides directed towards the endoplasmic reticulum or plasma membrane. Yeast strains expressing peptide-PhCCD1 constructs showed β-ionone yields up to 4-fold higher than the strain carrying the native enzyme. Our results demonstrate that protein engineering of CCDs significantly increases the yield of β-ionone synthesized by metabolically engineered yeast.

Background The basidiomycetous yeast Xanthophyllomyces dendrorhous has been described as a potential biofactory for terpenoid-derived compounds due to its ability to synthesize astaxanthin. Functional knowledge of the genes involved in terpenoid synthesis would create opportunities to enhance carotenoid production. A thiolase enzyme catalyzes the first step in terpenoid synthesis. Results Two potential thiolase-encoding genes were found in the yeast genome; bioinformatically, one was identified as an acetyl-CoA C-acetyltransferase (ERG10), and the other was identified as a 3-ketoacyl Co-A thiolase (POT1). Heterologous complementation assays in Saccharomyces cerevisiae showed that the ERG10 gene from X. dendrorhous could complement the lack of the endogenous ERG10 gene in S. cerevisiae, thereby allowing cellular growth and sterol synthesis. X. dendrorhous heterozygous mutants for each gene were created, and a homozygous POT1 mutant was also obtained. This mutant exhibited changes in pigment composition and higher ERG10 transcript levels than the wild type strain. Conclusions The results support the notion that the ERG10 gene in X. dendrorhous is a functional acetyl-CoA C-acetyltransferase essential for the synthesis of mevalonate in yeast. The POT1 gene would encode a functional 3-ketoacyl Co-A thiolase that is non-essential for cell growth, but its mutation indirectly affects pigment production. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0893-2) contains supplementary material, which is available to authorized users.

The market for industrial enzymes is increasing steadily. Hence, efficient expression systems and processes for the large-scale production of industrial enzymes are of common interest. The presented article deals with the recombinant production of a fungal lipase in yeasts, and with its large-scale, fermentative production up to 1.000 Litres.

The cysteine endoprotease papain is one of the most widely used plant proteases for industrial applications. However the traditional isolation of papain from the latex of papaya plants cannot cover the world-wide? demand. To increase papain production for industrial applications, several expression systems were studied in the last years for its recombinant production. While expression in Eschericha coli resulted in accumulation of insoluble protein, expression in baculovirus/ insect system and Saccharomyes cerevisiae resulted in low yields of soluble protein inadequate for large-scale production. Here we describe the heterologous expression of a synthetic codon-optimized propapain sequence in the Pichia pastoris strains X33 (Mut+) and KM71H (Muts). The recombinant propapain could be expressed as soluble protein and secreted in the culture medium through the α-factor signal peptide. Highest activities were obtained in the Muts strain when cultivated in complex medium. After purification by Ni- NTA chromatography 463 mg/L recombinant propapain was obtained comparable to the so far highest reported propapain yields in E. coli after protein solublilization and refolding and with a specific activity similar to a commercial papain from papaya latex.