Bioresource Technology Reports
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2026
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IF 5
Pengju Li,Yu Liu,Fei Li,Xianliang Yi,Yang Liu,Hao Zhou
Straw is an abundant renewable biomass resource, yet its microbial valorization remains constrained by lignocellulose recalcitrance and the limited characterization of cellulolytic bacteria from coastal and marine environments. Here, we isolated a novel cellulolytic strain, Mycobacterium sp. CBM1, from nearshore sediment in Liaodong Bay (China) using sodium carboxymethyl cellulose (CMC Na) as the sole carbon source. Congo red staining and 16S rRNA sequencing confirmed its cellulolytic phenotype and taxonomic identity. Enzyme assays demonstrated endoglucanase, exoglucanase, and β-glucosidase activities, with optimal production at pH 7, 2% salinity, NH 4 Cl as the nitrogen source, and CMC-Na (300–600 mPa·s) at 0.5 g/L. When cultivated with straw as the sole carbon source (5 g/L), CBM1 converted ∼20% of the substrate within 30 days, accompanied by a decrease in crystallinity index from 46.63% to 37.12%. Whole-genome sequencing revealed a CAZyme repertoire of 230 genes, including 76 glycoside hydrolases, supporting reconstruction of a putative cellulose degradation route. Structural modeling and molecular docking provided supportive hypotheses for substrate recognition by key cellulases. Collectively, these results provide a phenotype-genome-structure basis for developing bacterial candidates for sustainable straw bioconversion.
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BIOORGANIC CHEMISTRY
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2022
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IF 5.307
Xinqi Xu,Yajiao Zhang,Shaoyu Wang,Lian Xu,Bingmei Su,Lichao Wang,Juan Lin
Baeyer-Villiger monooxygenase (BVMO) mediated sulfoxidation is a sustainable approach for the synthesis of esomeprazole. In this work, a novel phenylacetone monooxygenase from Limnobacter sp. ( Ln PAMO) was found to have trace activity for synthesis of enantiopure esomeprazole. Through engineering in the substrate tunnel using a mutagenesis strategy called “nonpolarity paving” and some modifications in cofactor binding domains, a mutant harboring 15 mutations ( Ln PAMO Mu15) was obtained with 6.6 × 10 3 -fold higher activity to convert omeprazole sulfide into esomeprazole. The activities of the mutant for synthesis of ( S )-methyl phenyl sulfoxide and ( S )-pantoprazole also increased much, indicating the versatility of the mutant for sulfoxide synthesis. Importantly, no over-oxidation byproduct omeprazole sulfone was detected in the sulfoxidation products by both mass spectrometry and HPLC analysis. Then NADP-dependent Burkholderia stabili formate dehydrogenase was ligated behind Mu15 along with a ribosome binding site sequence in pET-28a for co-expression. By single whole-cell of recombinant Escherichia coli BL21 coexpressing Mu15 and formate dehydrogenase, omeprazole sulfide was efficiently converted into esomeprazole without production of sulfone (16 g/L substrate, enantiomeric excess > 99.9% ( S ) and > 99% conversion) and the space–time-yield reached 1.67 g product/L/h.
研究领域:
生物化学
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酶工程
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合成生物学
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Journal of Environmental Chemical Engineering
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2026
·Vol. 14
·期 3
·122943
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IF 7.5
Qiannan Li,Hanyu Pan,Yunna Jia,Zhenhua Ma,Ye Wang,Xiaojun Liang,Xiuzhen Yu,Yunhang Gao
The molecular mechanism by which microorganisms degrade the endocrine-disrupting contaminant 17β-estradiol (E2) at low temperatures remains largely unclear, with only limited studies available. Here, we investigated the adaptive strategy of the cryotolerant bacterium Rhodococcus sp . RCBS9 for sustaining E2 degradation at 10 °C, a temperature at which efficient estrogen degradation has rarely been reported. Using time-resolved multi-omics and phenotypic assays, we characterized a dynamic, staged adaptation process involving changes in oxidative stress defense, membrane composition, transcription factors, signaling factors, and stress proteins. We uncovered three major novelties. First, RCBS9 employs a distinct degradation pathway that first cleaves the saturated sterol rings, in contrast to the canonical 4,5-seco pathway that initiates with aromatic ring A cleavage. Second, we identified and functionally validated a cold-tolerant short-chain dehydrogenase/reductase (SDR) encoded by gene RQCS_RS03565 that converts E2 to estrone (E1), as confirmed by heterologous expression and site-directed mutagenesis. Third, subsequent sterol ring cleavage proceeds via a suite of oxidoreductases and hydrolases. The resulting aromatic intermediates are then mineralized through the β-ketoadipate pathway, as suggested by the coordinated upregulation of intradiol dioxygenase and carboxymuconolactone decarboxylase. Additionally, trace iron (50 μM) promoted E2 degradation and reduced E1 accumulation, partly attributable to enhanced metabolic activity and upregulation of iron-requiring enzyme genes. Overall, this work provides fundamental insights into a novel estrogen biodegradation logic under cold stress and proposes a practical iron-mediated strategy for low-temperature bioremediation.
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WATER RESEARCH
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2023
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IF 12.8
Di Cao,Xueqi Chen,Jun Nan,Aijie Wang,Zhiling Li
Influences of heavy metal exposure to the organohalide respiration process and the related molecular mechanism remain poorly understood. In this study, a non-obligate organohalide respiring bacterium, Pseudomonas sp. strain CP-1, was isolated and its molecular response to the five types of commonly existed heavy metal ions were thoroughly investigated. All types of heavy metal ions posed inhibitory effects on 2,4,6-trichlorophenol dechlorination activity and cell growth with the varied degree. Exposure to Cu (II) showed the most serious inhibitive effects on dechlorination even at the lowest concentration of 0.05 mg/L, while the inhibition by As (V) was the least with the removal kinetic constant k decreased to 0.05 under 50 mg/L. Further, multi-omics analysis found compared with Cu (II), As (V) exposure led to the insignificant downregulation of a variety of biosynthesis processes, which would be one possible account for the less inhibited activity. More importantly, the inhibited mechanisms on the organohalide respiration catabolism of strain CP-1 were firstly revealed. Cu (II) stress severely downregulated NADH generation during TCA cycle and electron donation of organohalide respiration process, which might decrease the reducing power required for organohalide respiration. While both Cu (II) and As (Ⅴ) inhibited substrate level phosphorylation during TCA cycle, as well as electron transfer and ATP generation during organohalide respiration. Meanwhile, CprA-2 was confirmed as the responsible reductive dehalogenase in charge of 2,4,6-TCP dechlorination, and transcriptional and proteomic studies confirmed the directly inhibited gene transcription and expression of CprA-2. The in-depth reveal of inhibitory effects and mechanism gave theoretical supports for alleviating heavy metal inhibition on organohalide respiration activity in groundwater co-contaminated with organohalides and heavy metals.
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Water
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2023
·Vol. 15
·期 20
·3544
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IF 3.4
Qingnan Sun,Xiaoping Zhang,Xin Zhang
In the treatment of wastewater containing only chemical oxygen demand (COD) byChlorellasp., the cell activity and proliferation ability ofChlorellasp. decreased with the culture time, which affected the removal of COD in wastewater. To solve these problems, theChlorellasp.–natural microorganism symbiosis system was prepared. The system was used to explore how natural microorganisms affect the cell activity and the proliferation ability ofChlorellasp. in wastewater. In the treatment of COD byChlorellasp., the removal rate of COD decreased from 45.47% to 28.88%, with a decrease in the cell activity and proliferation ability ofChlorellasp. In theChlorellasp.–natural microorganism symbiotic system, the removal rate of COD reached 45.75%. With the introduction of natural microorganisms, the circulation of CO2and O2betweenChlorellasp. and natural microorganisms promoted photosynthesis and respiration, which enhanced the cell activity ofChlorellasp. Under the condition that the dosage of natural microorganisms was between 1% and 6%, the concentration ofChlorellasp. was close to the logarithmic growth phase, which maintained the proliferation ability ofChlorellasp. At the same time, the natural microorganisms grew and proliferated in wastewater containing only COD through preying onChlorellasp.Keywords:Chlorellasp.;natural microorganisms;symbiosis system;cell activity;predation
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BIORESOURCE TECHNOLOGY
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2023
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IF 11.4
Zi-Xu Zhang,Lu-Wei Xu,Ying-Shuang Xu,Jin Li,Wang Ma,Xiao-Man Sun,He Huang
Schizochytrium sp., a microalga with high lipid content, holds the potential for co-producing docosahexaenoic acid (DHA) and carotenoids. In this study, the ability of Schizochytrium sp. to naturally produce carotenoids was systematically explored. Further, by enhancing the precursor supply of geranylgeranyl diphosphate, regulating carbon source through sugar limitation fermentation and employing a combination of response surface methodology and artificial neural networks to precisely optimize nitrogen sources, a new record of 43-fold increase in β-carotene titer was achieved in the 5L bioreactor (653.2 mg/L) . Meanwhile, a high DHA content was maintained (13.4 g/L). Furthermore, the use of corn stover hydrolysate has effectively lowered the production costs of carotenoid and DHA while sustaining elevated production levels (with total carotenoid titer and DHA titer reached 502.0 mg/L and 13.2 g/L, respectively). This study offers an efficient and cost-effective method for the co-production of carotenoid and DHA in Schizochytrium sp. .
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ENVIRONMENTAL RESEARCH
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2023
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IF 8.3
Shuai Zhang,Junfeng Su,Shuyu Liu,Yi Ren,Shumiao Cao
There is an urgent demand to investigate mechanisms for the improvement of denitrification in carbon-deficient environment, which will effectively reduce the eutrophication in water bodies polluted by nitrate. In this study, denitrifying bacterium Comamonas sp. YSF15 was used to explore the differences in different carbon source concentrations, with the complete genome, metabolomics, and other detecting methods. Results showed that strain YSF15 was able to achieve efficient denitrification, with complete pathways for denitrification and central carbon metabolism. The carbon deficiency prompted the bacteria to use extracellular amino acid-like metabolites initially, to alleviate inhibition and maintain bioactivity , which also facilitated glycogen storage. The biogenic inhibitors (tautomycin, navitoclax, and glufosinate) at extremely low level potentially favored the competitiveness and intraspecific utilization of extracellular polysaccharides (PS). Optimal solutions for bioaggregation in carbon-deficient condition are achieved by regulating the hydrophobicity , and hydrogen bond in extracellular metabolites. The strategy contributes to the maintenance of bioactivity and adaptation to carbon deficiency. Overall, this study provides a new perspective on understanding the denitrification strategies in carbon-deficient environment, and helps to improve the nitrate removal in low-carbon wastewater treatment .
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CHEMOSPHERE
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2023
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IF 8.8
Nan Zhou,Huihui Liu,Xianhai Yang,Peter Watson,Feifei Yang
The COVID-19 pandemic resulted in increasing the usage of iodinated contrast media (ICM), and thus an increase in the prevalence of ICM-contaminated wastewater. While ICM is generally safe, this has the potential to be problematic because as medical wastewater is treated and disinfected, various ICM-derived disinfection byproducts (DBPs) may be generated and released into the environment. However, little information was available about whether ICM-derived DBPs are toxic to aquatic organisms. In this study, the degradation of three typical ICM (iopamidol, iohexol, diatrizoate) at initial concentration of 10 μM and 100 μM in chlorination and peracetic acid without or with NH 4 + was investigated, and the potential acute toxicity of treated disinfected water containing potential ICM-derived DBPs on Daphnia magna , Scenedesmus sp. and Danio rerio was tested. The degradation results suggested that only iopamidol was significantly degraded (level of degradation >98%) by chlorination, and the degradation rate of iohexol and diatrizoate were significantly increased in chlorination with NH 4 + . All three ICM were not degraded in peracetic acid. The toxicity analysis results indicate that only the disinfected water of iopamidol and iohexol by chlorination with NH 4 + were toxic to at least one aquatic organism. These results highlighted that the potential ecological risk of ICM-contained medical wastewater by chlorination with NH 4 + should not be neglected, and peracetic acid may be an environment-friendly alternative for the disinfection of wastewater containing ICM.
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Marine Drugs
·
2023
·Vol. 21
·期 2
·133
·
IF 5.4
Congling Liu,Gong Chen,Hailian Rao,Xun Xiao,Yidan Chen,Cuiling Wu,Fei Bian,Hailun He
Crude enzymes produced by a marine bacteriumPseudoalteromonassp. JS4-1 were used to hydrolyze phycobiliprotein. Enzymatic productions showed good performance on DPPH radical and hydroxyl radical scavenging activities (45.14 ± 0.43% and 65.11 ± 2.64%, respectively), especially small peptides with MWCO <3 kDa. Small peptides were fractioned to four fractions using size-exclusion chromatography and the second fraction (F2) had the highest activity in hydroxyl radical scavenging ability (62.61 ± 5.80%). The fraction F1 and F2 both exhibited good antioxidant activities in oxidative stress models in HUVECs and HaCaT cells. Among them, F2 could upregulate the activities of SOD and GSH-Px and reduce the lipid peroxidation degree to scavenge the ROS to protectCaenorhabditis elegansunder adversity. Then, 25 peptides total were identified from F2 by LC-MS/MS, and the peptide with the new sequence of INSSDVQGKY as the most significant component was synthetized and the ORAC assay and cellular ROS scavenging assay both illustrated its excellent antioxidant property.Keywords:phycobiliprotein;antioxidant peptide;bacterial extracellular protease;enzymatic hydrolyzation;C. elegans
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SCIENCE OF THE TOTAL ENVIRONMENT
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2019
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IF 5.589
Feilong Dong,Qiufeng Lin,Jing Deng,Tuqiao Zhang,Cong Li,Xuedong Zai
The frequent occurrence of algal blooms in surface water has attracted more and more attention, which caused many water quality problems, including disinfection byproducts (DBPs). Algal organic matter (AOM) including intracellular organic matter (IOM) and extracellular organic matter (EOM), was a well-known precursor to DBPs formation in drinking water. This study evaluated the effect of ultraviolet (UV) irradiation on the cell integrity, IOM release and DBPs formation during subsequent chlorination of Chlorella sp. Results showed the damage rates of algal cells increased to 40.1% after the high UV irradiation of 528 mJ/cm 2 , which contributed to the release of IOM. In addition, UV irradiation was effective in reducing the formation of haloacetic acids (HAAs) both in AOM and IOM, but promoted the formation of nitrogenous DBPs (N-DBPs) from AOM in subsequent chlorination. Furthermore, neutral pH exerted a positive effect on the formation of DBPs. UV irradiation decreased the bromine substitution factor (BSF) value of AOM at a high bromide level. The BSF values increased with increasing of the concentration of bromide. Moreover, more amino acids and low molecular weight precursors were produced after UV irradiation in filtered supernatant, which contributed to the formation of N-DBPs with algal chlorination. Overall, this information demonstrated pre-oxidation of UV irradiation could be used to treat the algal-rich drinking water.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Tengda Ding,Kunde Lin,Bo Yang,Menting Yang,Juying Li
Carbamazepine (CAB) is a commonly detected pharmaceutical in the surface waters. In the present study, we evaluated the effect of humic acid (HA) and nitrogen species on the toxicity of CAB in a typical diatom Navicula sp., and its metabolic fate. The Navicula sp. showed a high sensitivity to CAB (72 h EC 50 = 0.179 mg L −1 ). The addition of HA (< 30 mg L −1 ) and ammonium could promote the growth of Navicula sp. during 6 d of exposure to CAB. CAB underwent rapid dissipation in the algal culture. The degradation of CAB in Navicula sp. cultures was significantly increased by the addition of HA and higher HA contents caused more degradation of CAB. Degradation and accumulation of CAB in Navicula sp. were significantly inhibited by ammonium. Five metabolites were found and possible degradation pathways of CAB in the algal cell were proposed. Methoxylation, demethylation, glucuronidation and hydroxylation contributed to CAB transformation in the algal cell.
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 5
·792-798
·
IF 1.071
Dong Lu,Xu Yongkai,Zhang Yun,Sun Aijun,Hu Yunfeng
Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals ( R )-1-phenylethanol and ( S )-1-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of ( S )-1-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an environmentally friendly method and will play critical roles in industrial asymmetric synthesis.
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