Secreted production of self-assembling peptides in Pichia pastoris by fusion to an artificial highly hydrophilic protein

The undecapeptides CH3CO-Gln-Gln-Arg-Phe-Gln-Trp-Gln-Phe-Glu-Gln-Gln-NH2 (P11-2) and CH3CO-Gln-Gln-Orn-Phe-Orn-Trp-Orn-Phe-Orn-Gln-Gln-NH2 (P11-14) have unique self-assembly characteristics and broad application potential. Originally, these peptides were produced by chemical synthesis, which is costly and difficult to scale up to industrial levels in an economically feasible way. This article describes the efficient secreted production of these peptides (with free termini and ornithines replaced with lysines) in the methylotrophic yeast Pichia pastoris. The peptides were produced as enterokinase-cleavable fusions to the C-terminus of an artificial Solubility-Enhancing Protein (SEP). In vitro, the fused highly hydrophilic SEP proved to prevent self-assembly of the peptides. The SEP domain also facilitates product detection and allows convenient separation of the fusion protein from the broth by simple salt precipitation. After cleavage of the purified fusion protein with enterokinase, the free undecapeptides were obtained and P11-2 spontaneously assembled into a self-supporting gel, as intended. The properties of the SEP carrier could be advantageous for the production of other peptides

Enhanced expression in tobacco of the gene encoding green fluorescent protein by modification of its codon usage

The gene encoding green fluorescent protein (GFP) from Aequorea victoria was resynthesized to adapt its codon usage for expression in plants by increasing the frequency of codons with a C or a G in the third position from 32 to 60%. The strategy for constructing the synthetic gfp gene was based on the overlap extension PCR method using 12 long oligonucleotides as the starting material and as primers. The new gene contains 101 silent nucleotide changes compared to its wild-type counterpart used in this study. Several transgenic tobacco lines containing the wild-type gfp gene contained minute amounts of a smaller protein cross-reacting with GFP antiserum, whereas only one protein of the expected size was found in transgenics with the synthetic gfp gene. The smaller protein was probably encoded by a truncated gfp mRNA created by splicing of a 84 bp cryptic intron as detected by a reverse transcription-PCR technique. A comparison of GFP production in transgenics with the wild-type and the synthetic gfp gene under the control of the enhanced CaMV 35S promoter showed that the large-scale alterations in the gfp gene increased the frequency of high expressors in the transgenic population but hardly changed the maximum GFP concentrations.The latter phenomenon may be attributed to a reduced regeneration capacity of transformed cells with higher GFP concentrations

Process for polylactic acid production using Monascus

A process for producing polylactic acid (PLA) comprising the steps: fermenting in a fermentation vessel a micro-organism of the genus Monascusin a medium at a pH less than or equal to 5 under conditions which produce lactic acid into the medium, converting the lacticacid produced into lactide, and polymerizing the lactide to form PLA

Use of Monascus in organic acid production

The present invention provides tools and methods for producing organic acids using strains of Monascus which are tolerant to high organic acid concentrations at low pH