Journal of bioscience and bioengineering最新文献

{"title":"Gene identification and enzymatic characterization of the initial enzyme in pyrimidine oxidative metabolism, uracil-thymine dehydrogenase","authors":"Chee-Leong Soong ,&nbsp;Kengo Deguchi ,&nbsp;Michiki Takeuchi ,&nbsp;Syoko Kozono ,&nbsp;Nobuyuki Horinouchi ,&nbsp;Dayong Si ,&nbsp;Makoto Hibi ,&nbsp;Sakayu Shimizu ,&nbsp;Jun Ogawa","doi":"10.1016/j.jbiosc.2024.02.004","DOIUrl":"10.1016/j.jbiosc.2024.02.004","url":null,"abstract":"<div><p>Uracil-thymine dehydrogenase (UTDH), which catalyzes the irreversible oxidation of uracil to barbituric acid in oxidative pyrimidine metabolism, was purified from <em>Rhodococcus erythropolis</em> JCM 3132. The finding of unusual stabilizing conditions (pH 11, in the presence of NADP⁺ or NADPH) enabled the enzyme purification. The purified enzyme was a heteromer consisting of three different subunits. The enzyme catalyzed oxidation of uracil to barbituric acid with artificial electron acceptors such as methylene blue, phenazine methosulfate, benzoquinone, and α-naphthoquinone; however, NAD⁺, NADP⁺, flavin adenine dinucleotide, and flavin mononucleotide did not serve as electron acceptors. The enzyme acted not only on uracil and thymine but also on 5-halogen-substituted uracil and hydroxypyrimidine (pyrimidone), while dihydropyrimidine, which is an intermediate in reductive pyrimidine metabolism, and purine did not serve as substrates. The activity of UTDH was enhanced by cerium ions, and this activation was observed with all combinations of substrates and electron acceptors.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 6","pages":"Pages 413-419"},"PeriodicalIF":2.8,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140131554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of a novel cell line, CHO-MK, derived from Chinese hamster ovary tissues for biologics manufacturing","authors":"Kenji Masuda ,&nbsp;Michi Kubota ,&nbsp;Yuto Nakazawa ,&nbsp;Chigusa Iwama ,&nbsp;Kazuhiko Watanabe ,&nbsp;Naoto Ishikawa ,&nbsp;Yumiko Tanabe ,&nbsp;Satoru Kono ,&nbsp;Hiroki Tanemura ,&nbsp;Shinichi Takahashi ,&nbsp;Tomohiro Makino ,&nbsp;Takeshi Okumura ,&nbsp;Takayuki Horiuchi ,&nbsp;Koichi Nonaka ,&nbsp;Sei Murakami ,&nbsp;Masamichi Kamihira ,&nbsp;Takeshi Omasa","doi":"10.1016/j.jbiosc.2024.02.005","DOIUrl":"10.1016/j.jbiosc.2024.02.005","url":null,"abstract":"<div><p>Chinese hamster ovary (CHO) cells are widely used as a host for producing recombinant therapeutic proteins due to advantages such as human-like post-translational modification, correct protein folding, higher productivity, and a proven track record in biopharmaceutical development. Much effort has been made to improve the process of recombinant protein production, in terms of its yield and productivity, using conventional CHO cell lines. However, to the best of our knowledge, no attempts have been made to acquire new CHO cell lines from Chinese hamster ovary. In this study, we established and characterized a novel CHO cell line, named CHO-MK, derived from freshly isolated Chinese hamster ovary tissues. Some immortalized cell lines were established via sub-culture derived from primary culture, one of which was selected for further development toward a unique expression system design. After adapting serum-free and suspension culture conditions, the resulting cell line exhibited a considerably shorter doubling time (approximately 10 h) than conventional CHO cell lines (approximately 20 h). Model monoclonal antibody (IgG₁)-producing cells were generated, and the IgG₁ concentration of fed-batch culture reached approximately 5 g/L on day 8 in a 200-L bioreactor. The cell bank of CHO-MK cells was prepared as a new host and assessed for contamination by adventitious agents, with the results indicating that it was free from any such contaminants, including infectious viruses. Taking these findings together, this study showed the potential of CHO-MK cells with a shorter doubling time/process time and enhanced productivity in biologics manufacturing.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 6","pages":"Pages 471-479"},"PeriodicalIF":2.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140110341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of antibody production performance change in Chinese hamster ovary cells using morphological profiling","authors":"Takumi Hisada ,&nbsp;Yuta Imai ,&nbsp;Yuto Takemoto ,&nbsp;Kei Kanie ,&nbsp;Ryuji Kato","doi":"10.1016/j.jbiosc.2024.01.011","DOIUrl":"10.1016/j.jbiosc.2024.01.011","url":null,"abstract":"<div><p>Monoclonal antibodies (mAbs) represent a significant segment of biopharmaceuticals, with the market for mAb therapeutics expected to reach $200 billion in 2021. Chinese Hamster Ovary (CHO) cells are the industry standard for large-scale mAb production owing to their adaptability and genetic engineering capabilities. However, maintaining consistent product quality is challenging, primarily because of the inherent genetic instability of CHO cells. In this study, we address the need for advanced technologies for quality monitoring of host cells in biopharmaceuticals. We highlight the limitations of traditional cell assessment techniques such as flow cytometry and propose a noninvasive, label-free image-based analysis method. By utilizing advanced image processing and machine learning, this technique aims to non-invasively and quantitatively evaluate subtle quality changes in suspension cells. The research aims to investigate the use of morphological analysis for identifying subtle alterations in mAb productivity of CHO cells, employing cells stimulated by compounds as a model for this study. Our results show that the mAb productivity of CHO cells (day 8) can be predicted only from their early morphological profile (day 3). Our study also discusses the importance of strategic methods for forecasting host cell mAb productivity using morphological profiles, as inferred from our machine learning models specialized in predictive score prediction and anomaly prediction.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 6","pages":"Pages 453-462"},"PeriodicalIF":2.8,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140110342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing synthesis of ethyl lactate in rice baijiu fermentation by adding recovered granular cells","authors":"Shoujie Du ,&nbsp;Liucui Yao ,&nbsp;Bin Zhong ,&nbsp;Junwei Qin ,&nbsp;Songgui He ,&nbsp;Youqiang Liu ,&nbsp;Zhenqiang Wu","doi":"10.1016/j.jbiosc.2024.02.002","DOIUrl":"10.1016/j.jbiosc.2024.02.002","url":null,"abstract":"<div><p>Ethyl lactate is the most abundant ester in semi-solid rice baijiu fermentation, affecting the flavor of baijiu to a great extent. The present study aimed to investigate the spatial distribution and formation contributor of ethyl lactate by removing the microorganisms and extracellular enzymes from the upper, middle, and lower fermentation broth during the later fermentation stage. The removal of suspended substances by centrifugation did not affect the ethyl lactate content in the top and middle fermentation broth containing free cells, enzymes, and starch particles. After day 5 of fermentation, only the lower fermentation broth containing granular cells attached to the starch could continue to accumulate lactic acid, thereby increasing the ethyl lactate content. The results showed that the chemical reactions were the main contributor to the increased ethyl lactate content at the anaphase of fermentation rather than enzymatic catalysis or microbial metabolism. Sequencing of granular cells revealed the main lactic acid producers at different fermentation stages. <em>Lactobacillus helveticus</em> showed the highest abundance of 94.45–95.40% on day 5, which decreased to 29.58–30.20% on day 15, while <em>Lactobacillus acetotolerans</em> showed the highest abundance of 47.93–49.72% at day 15. Additionally, the granular cells were recovered and used for supplementary inoculation in the next batch, which significantly increased the ethyl lactate content. This study provided a novel strategy for improving the ethyl lactate content in semi-solid baijiu fermentation.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 5","pages":"Pages 388-395"},"PeriodicalIF":2.8,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140068410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of heterologous expression and N-glycosylation on the hyperthermostable endoglucanase of Pyrococcus furiosus","authors":"Hironori Semba ,&nbsp;Haruka Kado Horiguchi ,&nbsp;Hirokazu Tsuboi ,&nbsp;Kazuhiko Ishikawa ,&nbsp;Akio Koda","doi":"10.1016/j.jbiosc.2024.02.006","DOIUrl":"10.1016/j.jbiosc.2024.02.006","url":null,"abstract":"<div><p>Hyperthermostable endoglucanases of glycoside hydrolase family 12 from the archaeon <em>Pyrococcus furiosus</em> (EGPf) catalyze the hydrolysis of β-1,4-glucosidic linkages in cellulose and β-glucan structures that contain β-1,3- and β-1,4-mixed linkages. In this study, EGPf was heterologously expressed with <em>Aspergillus niger</em> and the recombinant enzyme was characterized. The successful expression of EGPf resulted as N-glycosylated protein in its secretion into the culture medium. The glycosylation of the recombinant EGPf positively impacted the kinetic characterization of EGPf, thereby enhancing its catalytic efficiency. Moreover, glycosylation significantly boosted the thermostability of EGPf, allowing it to retain over 80% of its activity even after exposure to 100 °C for 5 h, with the optimal temperature being above 120 °C. Glycosylation did not affect the pH stability or salt tolerance of EGPf, although the glycosylated compound exhibited a high tolerance to ionic liquids. EGPf displayed the highest specific activity in the presence of 20% (v/v) 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), reaching approximately 2.4 times greater activity than that in the absence of [Bmim]Cl. The specific activity was comparable to that without the ionic liquid even in the presence of 40% (v/v) [Bmim]Cl. Glycosylated EGPf has potential as an enzyme for saccharifying cellulose under high-temperature conditions or with ionic liquid treatment due to its exceptional thermostability and ionic liquid tolerance. These results underscore the potential of N-glycosylation as an effective strategy to further enhance both the thermostability of highly thermostable archaeal enzymes and the hydrolysis of barley cellulose in the presence of [Bmim]Cl.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 5","pages":"Pages 329-334"},"PeriodicalIF":2.8,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140068409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterologous production of a new lanthipeptide boletupeptin using a cryptic biosynthetic gene cluster of the myxobacterium Melittangium boletus","authors":"Pratchaya Rukthanapitak ,&nbsp;Keita Saito ,&nbsp;Ryo Kobayashi ,&nbsp;Issara Kaweewan ,&nbsp;Shinya Kodani","doi":"10.1016/j.jbiosc.2024.02.001","DOIUrl":"10.1016/j.jbiosc.2024.02.001","url":null,"abstract":"<div><p>Myxobacteria have comparatively large genomes that contain many biosynthetic genes with the potential to produce secondary metabolites. Based on genome mining, we discovered a new biosynthetic gene cluster of class III lanthipeptide in the genome of the myxobacterium <em>Melittangium boletus</em>. The biosynthetic gene cluster contained a precursor peptide-coding gene <em>bolA</em>, and a class III lanthipeptide synthetase-coding gene <em>bolKC</em>. The expression vector containing <em>bolA</em> and <em>bolKC</em> was constructed using synthetic DNA with codon-optimized sequences based on the commercially available vector pET29b. Co-expression of the two genes in the host <em>Escherichia coli</em> BL21(DE3) yielded a new class III lanthipeptide named boletupeptin. The structure of boletupeptin was proposed to have one unit of labionin, as determined by mass spectrometry experiments after reductive cleavage. This is the first report of a class III lanthipeptide from a myxobacterial origin.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 5","pages":"Pages 354-359"},"PeriodicalIF":2.8,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140065213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High cell density cultivation of Corynebacterium glutamicum by deep learning-assisted medium design and the subsequent feeding strategy","authors":"Masaaki Konishi","doi":"10.1016/j.jbiosc.2024.01.018","DOIUrl":"10.1016/j.jbiosc.2024.01.018","url":null,"abstract":"<div><p>To improve the cell productivity of <em>Corynebacterium glutamicum</em>, its initial specific growth rate was improved by medium improvement using deep neural network (DNN)-assisted design with Bayesian optimization (BO) and a genetic algorithm (GA). To obtain training data for the DNN, experimental design with an orthogonal array was set up using a chemically defined basal medium (GC XII). Based on the cultivation results for the training data, specific growth rates were observed between 0.04 and 0.3/h. The resulting DNN model estimated the test data with high accuracy (R²_test ≥ 0.98). According to the validation cultivation, specific growth rates in the optimal media components estimated by DNN-BO and DNN-GA increased from 0.242 to 0.355/h. Using the optimal media (UCB_3), the specific growth rate, along with other parameters, was evaluated in batch culture. The specific growth rate reached 0.371/h from 3 to 12 h, and the dry cell weight was 28.0 g/L at 22.5 h. From the cultivation, the cell yields against glucose, ammonium ion, phosphate ion, sulfate ion, potassium ion, and magnesium ion were calculated. The cell yield calculation was used to estimate the required amounts of each component, and magnesium was found to limit the cell growth. However, in the follow-up fed-batch cultivation, glucose and magnesium addition was required to achieve the high initial specific growth rate, while appropriate feeding of glucose and magnesium during cultivation resulted in maintaining the high specific growth rate, and obtaining a cell yield of 80 g/L_ini.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 5","pages":"Pages 396-402"},"PeriodicalIF":2.8,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140021856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction of self-cloning Aspergillus oryzae strains with high production of multiple biomass-degrading enzymes on solid-state culture","authors":"Satoko Senoo ,&nbsp;Tomoko Shintani ,&nbsp;Shoko Nieda ,&nbsp;Takahiro Shintani ,&nbsp;Masahiro Kariyama ,&nbsp;Katsuya Gomi","doi":"10.1016/j.jbiosc.2023.12.005","DOIUrl":"10.1016/j.jbiosc.2023.12.005","url":null,"abstract":"<div><p><span><span>Filamentous fungi produce numerous industrially important </span>enzymes. Among them, </span><em>Aspergillus oryzae-</em>derived enzymes are widely used in various fermentation applications. In this study, we constructed self-cloning strains that overproduce multiple biomass-degrading enzymes under the control of a strong promoter of α-amylase-coding gene (<em>amyB</em>) using the industrial strain <em>A. oryzae</em><span> AOK11. Two strains (strains 2-4 and 3-26) were introduced with different combinations of genes encoding xylanase (</span><em>xynG1</em><span>), phytase (</span><em>phyA</em><span>), pectin lyase (</span><em>pelA</em><span>), and polygalacturonase (</span><em>pgaB</em><span><span>). These strains had at least one copy of each enzyme gene derived from the expression cassette in the genome. The transcription levels of enzyme-coding genes introduced were more than 100-fold higher than those in the parent strain. Reflecting the high transcription levels, the activities of the enzymes derived from the expression cassettes of these two strains were significantly higher than those of the parent strain in both liquid and solid-state cultures. Even in ventilated solid-state cultures that were scaled up using mechanical equipment for practical applications, the two strains showed significantly higher </span>enzyme activity than the parent strain. These results indicate that these strains constructed using a safe self-cloning technique represent industrially valuable practical strains that can be used in the food and livestock industries.</span></p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 3","pages":"Pages 204-210"},"PeriodicalIF":2.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139495413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of cheese rancidity-related lipases in Aspergillus oryzae AHU 7139","authors":"Napaporn Chintagavongse ,&nbsp;Haruto Kumura ,&nbsp;Toru Hayakawa ,&nbsp;Jun-ichi Wakamatsu ,&nbsp;Koichi Tamano","doi":"10.1016/j.jbiosc.2024.01.016","DOIUrl":"10.1016/j.jbiosc.2024.01.016","url":null,"abstract":"<div><p>The adjunct product with enzymatic activity from <em>Aspergillus oryzae</em> is beneficial for flavor enrichment in the ripened cheese. However, an excessive lipolytic reaction leads to the release of volatile free fatty acids. Accordingly, a strong off-flavor (i.e., rancidity) has been detected when <em>A. oryzae</em> AHU 7139 is used. To identify the rancidity-related lipase from this strain, we evaluated the substrate specificity and lipase distribution using five mutants cultured on a whey-based solid medium under different initial pH conditions. The results showed a higher diacylglycerol lipase activity than triacylglycerol lipase activity. Moreover, an initial pH of 6.5 for the culture resulted in higher lipolytic activity than a pH of 4.0, and most of the activity was found in the extracellular fraction. Based on the gene expression analysis by real-time polymerase chain reaction and location and substrate specificity, five genes (No. 1, No. 19, <em>mdlB</em>, <em>tglA</em>, and <em>cutL</em>) were selected among 25 annotated lipase genes to identify the respective knockout strains. Because Δ<em>tglA</em> and Δ<em>mdlB</em> showed an outstanding involvement in the release of free fatty acids, these strains were applied to <em>in vitro</em> cheese curd experiments. In conclusion, we posit that triacylglycerol lipase (TglA) plays a key role as the trigger of rancidity and the resulting diglycerides have to be exposed to diacylglycerol lipase (MdlB) to stimulate rancidity in cheese made with <em>A. oryzae</em> AHU 7139. This finding could help screen suitable <em>A.</em> <em>oryzae</em> strains as cheese adjuncts to prevent the generation of the rancid-off flavor.</p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 5","pages":"Pages 381-387"},"PeriodicalIF":2.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140012597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolome analysis of metabolic burden in Escherichia coli caused by overexpression of green fluorescent protein and delta-rhodopsin","authors":"Chinatsu Matsuyama ,&nbsp;Taisuke Seike ,&nbsp;Nobuyuki Okahashi ,&nbsp;Teppei Niide ,&nbsp;Kiyotaka Y. Hara ,&nbsp;Yoko Hirono-Hara ,&nbsp;Jun Ishii ,&nbsp;Hiroshi Shimizu ,&nbsp;Yoshihiro Toya ,&nbsp;Fumio Matsuda","doi":"10.1016/j.jbiosc.2023.12.003","DOIUrl":"10.1016/j.jbiosc.2023.12.003","url":null,"abstract":"<div><p><span>Overexpression of proteins by introducing a DNA vector<span> is among the most important tools for the metabolic engineering of microorganisms such as </span></span><em>Escherichia coli.</em><span> Protein overexpression imposes a burden on metabolism because metabolic pathways must supply building blocks for protein and DNA synthesis. Different </span><em>E. coli</em> strains have distinct metabolic capacities. In this study, two proteins were overexpressed in four <em>E. coli</em><span> strains (MG1655(DE3), W3110(DE3), BL21star(DE3), and Rosetta(DE3)), and their effects on metabolic burden were investigated. Metabolomic analysis showed that </span><em>E. coli</em><span><span> strains overexpressing green fluorescent protein had decreased levels of several metabolites, with a positive correlation between the number of reduced metabolites and green fluorescent </span>protein expression levels. Moreover, nucleic acid-related metabolites decreased, indicating a metabolic burden in the </span><em>E. coli</em><span><span> strains, and the growth rate and protein expression levels were improved by supplementation with the five </span>nucleosides<span>. In contrast, two strains overexpressing delta rhodopsin, a microbial membrane rhodopsin from </span></span><span><em>Haloterrigena</em><em> turkmenica</em></span><span>, led to a metabolic burden and decrease in the amino acids<span> Ala, Val, Leu, Ile, Thr, Phe, Asp, and Trp, which are the most frequent amino acids in the delta rhodopsin protein sequence<span>. The metabolic burden caused by protein overexpression was influenced by the metabolic capacity of the host strains and the sequences of the overexpressed proteins. Detailed characterization of the effects of protein expression on the metabolic state of engineered cells using metabolomics will provide insights into improving the production of target compounds.</span></span></span></p></div>","PeriodicalId":15199,"journal":{"name":"Journal of bioscience and bioengineering","volume":"137 3","pages":"Pages 187-194"},"PeriodicalIF":2.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139570559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}