High level expression of organophosphorus hydrolase in Pichia pastoris by multicopy ophcM assembly

Effect of tandem repeats of antimicrobial peptide CC34 on production of target proteins and activity of Pichia pastoris

Antimicrobial peptides (AMPs) are attracting attention in the fields of medicine, food, and agriculture because of their broad-spectrum antibacterial properties, low resistance, and low-residue in the body. However, the low yield and instability of the prepared AMP drugs limit their application. In this study, we designed a tetramer of the AMP CC34, constructed and transfected two recombinant expression vectors with pGAPZαA containing a haploid CC34 and tetraploid CC34 (CC34-4js) into Pichia pastoris to explore the effect of biosynthesized peptides. The results showed that CC34 and CC34-4js expression levels were 648.2 and 1105.3 mg/L, respectively, in the fermentation supernatant of P. pastoris. The CC34-4js tetramer showed no antibacterial activity, could be cleaved to the monomer using formic acid, and the hemolytic rate of the polyploid was slightly lower than that of monomeric CC34. The average daily gain, average daily feed intake, feed conversion ratio and immune organ index of rats fed CC34 and CC34-4js showed no differences. In conclusion, CC34-4js exhibited a higher yield and lower hemolysis in P. pastoris than those of CC34. Finally, CC34 and CC34-4js enterokinase lysates showed similar antibacterial activity and both expressed peptides potentially improved the growth performance and organ indices of rats.

Heterologous expression of a deacetylase and its application in L-glufosinate preparation

With potent herbicidal activity, biocatalysis synthesis of L-glufosinate has drawn attention. In present research, NAP-Das2.3, a deacetylase capable of stereoselectively resolving N-acetyl-L-glufosinate to L-glufosinate mined from Arenimonas malthae, was heterologously expressed and characterized. In Escherichia coli, NAP-Das2.3 activity only reached 0.25 U/L due to the formation of inclusive bodies. Efficient soluble expression of NAP-Das2.3 was achieved in Pichia pastoris. In shake flask and 5 L bioreactor fermentation, NAP-Das2.3 activity by recombinant P. pastoris reached 107.39 U/L and 1287.52 U/L, respectively. The optimum temperature and pH for N-acetyl-glufosinate hydrolysis by NAP-Das2.3 were 45 °C and pH 8.0, respectively. The Km and Vmax of NAP-Das2.3 towards N-acetyl-glufosinate were 25.32 mM and 19.23 μmol mg-1 min-1, respectively. Within 90 min, 92.71% of L-enantiomer in 100 mM racemic N-acetyl-glufosinate was converted by NAP-Das2.3. L-glufosinate with high optical purity (e.e.P above 99.9%) was obtained. Therefore, the recombinant NAP-Das2.3 might be an alternative for L-glufosinate biosynthesis.

Organophosphorus pesticide tolerance of transgenic Arabidopsis thaliana by bacterial ophB gene encode organophosphorus hydrolase

Organophosphate hydrolase (OphB) gene from Pseudomonas sp. was transferred into Arabidopsis plants to observe the bioremediation ability and tolerance level of the transgenic plant to organophosphate pesticides contaminants. Gene transfer was observed by PCR of the transgenic Arabidopsis plants' genomic DNA. Expression of ophB gene and protein levels in the transgenic Arabidopsis plants was observed by western blot analysis. The transgenic plants were resistant and tolerant to chlorpyrifos (an organophosphate pesticide), as evidenced by a toxicity test, where the transgenic plants produced greater shoot and root biomass than that of wild type plants. The fresh weight of transgenic Arabidopsis plants' did not reduced significantly till 400 ppm chlorpyrifos treatment, but fresh weight of wild type Arabidopsis plants' significantly reduced by the application of 100 ppm chlorpyrifos. Moreover, in 600 ppm chlorpyrifos liquid culture, transgenic Arabidopsis plants' produced 1.34 g biomass from 100 seeds, but wild type Arabidopsis plants' produced only 0.24 g biomass from 100 seeds. This study indicates that transgenic Arabidopsis plants having ophB gene increase the tolerance level of organophosphate pesticides.

Overview of a bioremediation tool: organophosphorus hydrolase and its significant application in the food, environmental, and therapy fields

In the past decades, the organophosphorus compounds had been widely used in the environment and food industries as pesticides. Owing to the life-threatening and long-lasting problems of organophosphorus insecticide (OPs), an effective detection and removal of OPs have garnered growing attention both in the scientific and practical fields in recent years. Bacterial organophosphorus hydrolases (OPHs) have been extensively studied due to their high specific activity against OPs. OPH could efficiently hydrolyze a broad range of substrates both including the OP pesticides and some nerve agents, suggesting a great potential for the remediation of OPs. In this review, the microbial identification, molecular modification, and practical application of OPHs were comprehensively discussed.Key points• Microbial OPH is a significant bioremediation tool against OPs.• Identification and molecular modification of OPH was discussed in detail.• The applications of OPH in food, environmental, and therapy fields are presented.

In-depth biochemical identification of a novel methyl parathion hydrolase from Azohydromonas australica and its high effectiveness in the degradation of various organophosphorus pesticides

Organophosphorus pesticides are highly toxic phosphate compounds with the general structure of O = P(OR)₃ and threaten human health seriously. Methyl parathion hydrolase from microbial is an important enzyme to degrade organophosphorus pesticides (OPs) into less toxic or nontoxic compounds like. p-nitrophenol and diethyl phosphate. Here, a gene encoding methyl parathion hydrolase from Azohydromonas australica was firstly cloned and expressed in Escherichia coli. The recombinant hydrolase showed its optimal pH and temperature at pH 9.5 and 50 °C. Leveraging 1 mM Mn²⁺, the enzyme activity was significantly enhanced by 29.3-fold, and the thermostability at 40 and 50 °C was also improved. The recombinant MPH showed the specific activity of 4.94 and 16.0 U/mg towards methyl parathion and paraoxon, respectively. Moreover, A. australica MPH could effectively degrade various of OPs pesticides including methyl parathion, paraoxon, dichlorvos and chlorpyrifos in a few minutes, suggesting a great potential in the bioremediation of OPs pesticides.

Multiple strategies to improve the yield of chitinase a from Bacillus licheniformis in Pichia pastoris to obtain plant growth enhancer and GlcNAc

Chitinase and chitin-oligosaccaride can be used in multiple field, so it is important to develop a high-yield chitinase producing strain. Here, a recombinant Pichia pastoris with 4 copies of ChiA gene from Bacillus licheniformis and co-expression of molecular chaperon HAC1 was constructed. The amount of recombinant ChiA in the supernatant of high-cell-density fermentation reaches a maximum of 12.7 mg/mL, which is 24-fold higher than that reported in the previous study. The recombinant ChiA can hydrolyze 30% collodidal chitin with 74% conversion ratio, and GlcNAc is the most abundant hydrolysis product, followed by N, N′-diacetylchitobiose. Combined with BsNagZ, the hydrolysate of ChiA can be further transformed into GlcNAc with 88% conversion ratio. Additionally, the hydrolysate of ChiA can obviously accelerate the germination growth of rice and wheat, increasing the seedling height and root length by at least 1.6 folds within 10 days.

Pichia pastoris — recombinant enzyme producent for environment treatment — review

Since environmental pollution is increasing, scientists try to find a sustainable way for its clean up and for environment protection. Due to increasing knowledge of genetics and recombinant technologies, recombinant enzymes have been increasingly applied for these purposes. This article deals with the possibilities of environmental treatment with different types of enzymes produced by P. pastoris. Environment is polluted mostly with pesticides, wastewaters, phenol compounds, plastics, toxic compounds, wastes from medical treatment, etc. All these compounds have to be eliminated considering the deteriorating biodiversity, human health, and condition of plants. Enzymes are an environmentally friendly way of such treatment.

Efficient Degradation of Malathion in the Presence of Detergents Using an Engineered Organophosphorus Hydrolase Highly Expressed by Pichia pastoris without Methanol Induction

The biodegradation of pesticides by organophosphorus hydrolases (OPHs) requires an efficient enzyme production technology in industry. Herein, a Pichia pastoris strain was constructed for the extracellular expression of PoOPH_M9, an engineered malathion-degrading enzyme. After optimization, the maximum titer and yield of fermentation reached 50.8 kU/L and 4.1 g_protein/L after 3 days, with the highest space-time yield (STY) reported so far, 640 U L^-1 h^-1. PoOPH_M9 displayed its high activity and stability in the presence of 0.1% (w/w) plant-derived detergent. Only 0.04 mg/mL enzyme could completely remove 0.15 mM malathion in aqueous solution within 20 min. Furthermore, 12 μmol malathion on apples and cucumbers surfaces was completely removed by 0.05 mg/mL PoOPH_M9 in tap water after 35 min washing. The efficient production of the highly active PoOPH_M9 has cleared a major barrier to biodegradation of pesticide residues in food industry.

High-level expression of a ZEN-detoxifying gene by codon optimization and biobrick in Pichia pastoris

The mycotoxin zearalenone (ZEN) can be degraded by a lactone hydrolase ZHD, which was derived from Gliocladium roseum. Here, based on the native ZHD encoding gene zhd101, a codon optimized zhd gene was synthesized, which was used for high expression of ZHD in Pichia pastoris GS115. Meanwhile, to further improve the expression of recombinant ZHD, the plasmids containing 1 to 4 copies of the zhd expression cassette were constructed, respectively, using the biobrick method. The protein expression in the recombinant P. pastoris X3c, which was transformed with the plasmid containing 3 copies of zhd expression cassette, was the highest. In addition, the enzymatic activity of ZHD against ZEN was defined for the first time based on a standard curve of peak area vs ZEN concentration. The ZEN degradation activity of ZHD from shake flask fermentation was calculated as 22.5U/mL with the specific activity of 4976.5U/mg. Furthermore, the high-density fermentation of P. pastoris X3c strain was also performed in 5L fermenter. The maximum enzyme activity of the supernatant was 150.1U/mL, which were 6.7-fold higher than that of the shake flask fermentation.

High-level expression and characterization of a novel serine protease in Pichia pastoris by multi-copy integration

A novel serine protease from Trichoderma koningii (SPTK) was synthesized and expressed in Pichia pastoris. The recombinant SPTK was completely inhibited by phenyl methyl sulfonyl fluoride (PMSF), suggesting that SPTK belonged to the subgroup of serine proteases. The optimum pH and temperature for the recombinant SPTK reaction were 6.0 and 55°C, respectively. SPTK performed a tolerance to most organic solvents and metal ions, and the addition of Triton X-100 exhibited an activation of SPTK up to 243% of its initial activity but SDS strongly inhibited. Moreover, our study showed that a portion of SPTK was N-glycosylated during fermentation. The activity and thermal stability of the recombinant SPTK were improved after the removal of glycosylation, and the N-glycosylation of SPTK could be efficiently removed through co-culture with P. pastoris strains expressing Endo-β-N-acetylglucosaminidase H. We constructed expression vectors harboring from one to four repeats of Sptk-expressing cassettes via an in vitro BioBrick assembly approach. And the result of quantitative polymerase chain reaction (qPCR) indicated that the tandem expression cassettes were integrated into the genome of P. pastoris through a single recombination event. These strains were used to study the correlation between the gene copy number and the expression level of SPTK. The results of qPCR and enzyme activity assays indicated that the copy number variation of Sptk gene generally had a positive effect on the expression level of SPTK, while an increase in integration of target gene did not guarantee its high expression. The maximum yield and specific activity of SPTK in P. pastoris were obtained from the recombinant yeast strain harboring two-copy tandem Sptk-expressing cassettes, the yield reached 0.48g/l after a 6-d induction using menthol in shake flasks and 3.2g/l in high-density fermentation with specific activity of 5200U/mg. In addition, the recombinant SPTK could efficiently degrade chicken feather and hydrolyzed the gelatin layer of photographic film. These properties made the recombinant SPTK a suitable candidate for industrial applications and for eliminating the pollution of keratin.