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Yeasts are used to produce a myriad of value-added compounds. Engineering yeasts into cost-efficient cell factories is greatly facilitated by the availability of genome editing tools. While traditional engineering techniques such as homologous recombination-based gene knockout and pathway integration continue to be widely used, novel genome editing systems including multiplexed approaches, bacteriophage integrases, CRISPR-Cas systems, and base editors are emerging as more powerful toolsets to accomplish rapid genome scale engineering and phenotype screening. In this review, we summarized the techniques which have been successfully implemented in model yeast Saccharomyces cerevisiae as well as non-conventional yeast species. The mechanisms and applications of various genome engineering systems are discussed and general guidelines to expand genome editing systems from S. cerevisiae to other yeast species are also highlighted. [ABSTRACT FROM AUTHOR]

As a significant platform chemical, 2, 3-butanediol (2, 3-BD) has found wide applications in industry. The success of microbial 2, 3-BD production was limited by the use of pathogenic microorganisms and low titer in engineered hosts. The utilization of cheaply available feedstock such as lignocellulose was another major challenge to achieve economic production of 2, 3-BD. To address those issues, engineering strategies including both genetic modifications and process optimization have been employed. In this review, we summarized the state-of-the-art progress in the biotechnological production of 2, 3-BD. Metabolic engineering and process engineering strategies were discussed. [ABSTRACT FROM AUTHOR]

Pichia pastoris has been recognized as one of the most industrially important hosts for heterologous protein production. Despite its high protein productivity, the optimization of P. pastoris cultivation is still imperative due to strain- and product-specific challenges such as promoter strength, methanol utilization type and oxygen demand. To address the issues, strategies involving genetic and process engineering have been employed. Optimization of codon usage and gene dosage, as well as engineering of promoters, protein secretion pathways and methanol metabolic pathways have proved beneficial to innate protein expression levels. Large-scale production of proteins via high cell density fermentation additionally relies on the optimization of process parameters including methanol feed rate, induction temperature and specific growth rate. Recent progress related to the enhanced production of proteins in P. pastoris via various genetic engineering and cultivation strategies are reviewed. Insight into the regulation of the P. pastoris alcohol oxidase 1 (AOX1) promoter and the development of methanol-free systems are highlighted. Novel cultivation strategies such as mixed substrate feeding are discussed. Recent advances regarding substrate and product monitoring techniques are also summarized. Application of P. pastoris to the production of biodiesel and other value-added products via metabolic engineering are also reviewed. P. pastoris is becoming an indispensable platform through the use of these combined engineering strategies. [ABSTRACT FROM AUTHOR]

Novel xylanase (EC 3.2.1.8) is in great demand due to its industrial significance. In this study, we have developed and characterized a novel xylanase-producing yeast strain. This mature xylanase gene xyn 11A consists of 870 base pairs and belongs to GH11 family. The gene sequence was optimized and synthesized, and was then cloned into yeast vector pGAPZαA under the control of the constitutive GAP promoter. SDS-PAGE analysis indicates that Xyn11A is extracellularly expressed as a glycosylated protein in P. pastoris . Xyn11A is optimally active at 70 °C and pH 7.4. This xylanase retained more than 90% of its activity after incubation at 50 °C and 60 °C for up to 1 h. Xyn11A is also stable over a wide range of pH (2.0–11.0). Most metal ions tested such as copper (Cu 2+ ) and lead (Pb 2+ ) have little inhibitory effects on Xyn11A. It is also resistant to pepsin and proteinase K digestion, retaining 80% and 90% of its activity after digestion at 37 °C for 1 h, respectively. Those superior properties make Xyn11A a robust xylanase with great potential for industrial use. To the best of our knowledge, this is the first report of xylanase from the fungus Corynascus thermophilus . [ABSTRACT FROM AUTHOR]

Yarrowia lipolytica , an oleaginous yeast with the GRAS status, has been developed as a platform for the chemical production. Promoter engineering is an important approach to regulating gene expression at the transcriptional level, which is of great significance in constructing microbial cell factories. Although some work on promoter study has been carried out in Y. lipolytica , obtained achievements still need further replenishment and development, compared explicitly with Saccharomyces cerevisiae , Bacillus subtilis , and other microorganisms. For this, we screened 81 endogenous promoters in Y. lipolytica , mainly involved in carbon metabolism and nitrogen metabolism. As a result, we obtained 15 strong promoters, 41 medium strength promoters, and 25 weak promoters, with the strength spanning from 0.06 % to 1.60-fold of P TEF promoter. Moreover, as a proof-of-concept, the identified promoter library was applied for expressing UDP-glycosyltransferase to produce salidroside, resulting in a production of 95.64 mg/l in shake flask, which is 3.92-times that of the parental strain. In general, our study provides a unique and available endogenous promoter library for Y. lipolytica. [Display omitted] • Obtaining a promoter library with the strength spanning from 0.06 % to 160 % of P TEF. • Characterizing 15 strong promoters, 41 medium promoters, and 25 weak promoters. • The strongest promoter is P MnDH2 (YALI0D18964g), 1.60-fold of the strength of P TEF. • The weakest promoter is P PHO89 (YALI0E23859g), 0.06 % of the strength of P TEF. [ABSTRACT FROM AUTHOR]

Optical diamond materials are essential for infrared optical windows, microwave windows, and laser windows due to their exceptional properties. However, dark features inside the diamond are significant factors limiting optical properties, particularly at high deposition rates. This work focuses on adjusting crystallographic parameters to prepare (110) oriented optical-grade polycrystalline diamond films, aiming to mitigate dark features. Diamond films deposited via microwave plasma chemical vapor deposition (MPCVD) exhibit discernible quality stratification. Characterization analysis of diamond film samples with varying levels of black defects reveals a correlation: films with higher dark feature content tend to exhibit a preference for the (111) orientation, accompanied by a significant presence of penetration twins and interstitial voids. Conversely, transparent diamond films demonstrate a prominent (110) orientation, featuring numerous contact twins that alleviate competition from penetration twins and original grains during growth. Electron backscatter diffraction (EBSD) and scanning electron microscope (SEM) results reveal that transparent diamond films cultivated with a pronounced preference for the (110) orientation manifest consistent and seamless contact twins, leading to fewer dark features and improved optical transmittance. In contrast, (111) oriented diamond film exhibits numerous penetration twins, and holes form between them. Based on the analysis, 5-inch optical polycrystalline diamond films with (110) orientation were achieved successfully by suppressing dark features. [ABSTRACT FROM AUTHOR]

Unlabelled Image • Annual consumption of phosphate fertilizer in China has decreased after 2014. • Mean content of Cd was 0.75 mg/kg based on 1222 phosphate fertilizer samples. • MAP/DAP was main sources of Cd input from phosphate fertilizer in 2016. • The spatial and temporal distribution of Cd input from phosphate fertilizer was investigated. Phosphate fertilizer applications are an important source of soil Cd in China. However, the input of Cd from phosphate fertilizer has always been neglected in China because of its low content. In this paper, we calculated the Cd input from phosphate fertilizer in China during 2006–2016. According to the data, the total phosphate fertilizer consumption and agriculture application rate tended to decrease after 2014. In 2016, the phosphate fertilizer application rate ranged from 12.14 to 99.38 kg/ha with a mean value of 42.70 kg/ha, and excessive fertilizer application occurred in Xinjiang, Henan, and Hubei Provinces. The Cd content in phosphate fertilizer was 0.75 mg/kg based on 1222 samples. The national Cd input from phosphate fertilizer was estimated to be 10.52 tons in 2016, with DAP/MAP being the largest contributor, accounting for 83.31% of the total input. These findings demonstrate the necessity of performing assessments to regulate the utilization of phosphate fertilizer in China, especially in Henan and Xinjiang Provinces. [ABSTRACT FROM AUTHOR]

Abstract: Background: Inhibition of return (IOR) has been tested in patients with schizophrenia with contradictory results. Some studies indicated that patients with schizophrenia have normal levels of IOR; however, other studies reported delayed or blunted IOR. Inconsistency in findings might be due to differences across studies in relevant aspects associated with disease, such as heterogeneity of the disorder, different medications, onset and severity of the illness. The present study was to explore different patterns of IOR in antipsychotic medication free first-episode schizophrenia and chronic schizophrenia. Methods: Forty two patients with first-episode schizophrenia, 44 patients with chronic schizophrenia, and 38 healthy controls were included in the study. All subjects went through a covert orienting of attention task with seven stimulus onset asynchrony (SOA) intervals (400ms, 500ms, 600ms, 700ms, 800ms, 1200ms and 1500ms). Results: Compared with healthy controls, the magnitude and onset of IOR in first-episode patients with schizophrenia were intact. However, in patients with chronic schizophrenia, there was an attenuated cuing effect especially at SOA 700ms; in addition, there was a robust IOR until at SOAs 800ms or above. Moreover, the illness duration and the number of psychotic episodes were significantly correlated with the validity effect at SOAs 400ms and 600ms. Conclusion: Our study suggests that deficient IOR presents in chronic but not in first-episode patients with schizophrenia. IOR deficit in schizophrenia may begin during the course of illness and deteriorate over the course of illness. Our findings are consistent with the neurodegenerative model of schizophrenia. [Copyright &y& Elsevier]