Identification of sucrose synthase from Micractinium conductrix to favor biocatalytic glycosylation.

Sucrose synthase (SuSy, EC 2.4.1.13) is a unique glycosyltransferase (GT) for developing cost-effective glycosylation processes. Up to now, some SuSys derived from plants and bacteria have been used to recycle uridine 5'-diphosphate glucose in the reactions catalyzed by Leloir GTs. In this study, after sequence mining and experimental verification, a SuSy from Micractinium conductrix (McSuSy), a single-cell green alga, was overexpressed in Escherichia coli, and its enzymatic properties were characterized. In the direction of sucrose cleavage, the specific activity of the recombinant McSuSy is 9.39 U/mg at 37°C and pH 7.0, and the optimum temperature and pH were 60°C and pH 7.0, respectively. Its nucleotide preference for uridine 5'-diphosphate (UDP) was similar to plant SuSys, and the enzyme activity remained relatively high when the DMSO concentration below 25%. The mutation of the predicted N-terminal phosphorylation site (S31D) significantly stimulated the activity of McSuSy. When the mutant S31D of McSuSy was applied by coupling the engineered Stevia glycosyltransferase UGT76G1 in a one-pot two-enzyme reaction at 10% DMSO, 50 g/L rebaudioside E was transformed into 51.06 g/L rebaudioside M in 57 h by means of batch feeding, with a yield of 76.48%. This work may reveal the lower eukaryotes as a promising resource for SuSys of industrial interest.

Electroactive microorganisms synthesizing iron sulfide nanoparticles for enhanced hexavalent chromium removal in microbial fuel cells.

Microbial fuel cells (MFCs) have been considered a promising technology for Cr6+ removal, but they are limited by Cr6+-reducing biocathodes with low extracellular electron transfer (EET) and poor microbial activity. In this study, three kinds of nano-FeS hybridized electrode biofilms, obtained through synchronous biosynthesis (Sy-FeS), sequential biosynthesis (Se-FeS) and cathode biosynthesis (Ca-FeS), were applied as biocathodes for Cr6+ removal in MFCs. The Ca-FeS biocathode exhibited the best performance due to the superior properties of biogenic nano-FeS (e.g., more synthetic amount, smaller particle size, better dispersion). The MFC with the Ca-FeS biocathode achieved the highest power density (42.08 ± 1.42 mW/m2) and Cr6+ removal efficiency (99.18 ± 0.1 %), which were 1.42 and 2.08 times as high as those of the MFC with the normal biocathode, respectively. The synergistic effects of nano-FeS and microorganisms enhanced the bioelectrochemical reduction of Cr6+, first realizing deep reduction of Cr6+ to Cr0 in biocathode MFCs. This significantly alleviated the cathode passivation caused by Cr3+ deposition. In addition, the hybridized nano-FeS as "armor" layers protected the microbes from toxic attack by Cr6+, improving the biofilm physiological activity and extracellular polymeric substances (EPS) secretion. The hybridized nano-FeS as "electron bridges" facilitated the microbial community to form a balanced, stable and syntrophic ecological structure. This study proposes a novel strategy through the cathode in-situ biosynthesis of nanomaterials to fabricate hybridized electrode biofilms with enhanced EET and microbial activity for toxic pollutant treatment in bioelectrochemical systems.

Three Glycosyltransferase Mutants in a One-Pot Multi-enzyme System with Enhanced Efficiency for Biosynthesis of Quercetin-3,4'-O-diglucoside.

Quercetin-3,4'-O-diglucoside (Q3,4'G), among the major dietary flavonoids, is superior to quercetin aglycone or quercetin monoglucoside in solubility. However, its low content in nature makes it hard to be prepared in large quantities by traditional extraction methods. In the present study, the F378S mutant of UGT78D2 (78D2_F378S) derived from Arabidopsis thaliana with improved regioselectivity and the V371A mutant of UGT73G1 (73G1_V371A) derived from Allium cepa were adopted to realize a two-step continuous glycosylation of quercetin to produce Q3,4'G. The mutation S31D was introduced to the sucrose synthase from Micractinium conductrix with enhanced activity, which was responsible for regenerating UDP-glucose by coupling with 78D2_F378S and 73G1_V371A. Using the aforementioned enzymes, prepared from the three-enzyme co-expression strain, 4.4 ± 0.03 g/L (7.0 ± 0.05 mM, yield 21.2%) Q3,4'G was produced from 10 g/L quercetin after reaction for 24 h at 45 °C.

Improved performance of Cr(vi)-reducing microbial fuel cells by nano-FeS hybridized biocathodes.

Biocathode microbial fuel cells (MFCs) show promise for Cr(vi)-contaminated wastewater treatment. However, biocathode deactivation and passivation caused by highly toxic Cr(vi) and nonconductive Cr(iii) deposition limit the development of this technology. A nano-FeS hybridized electrode biofilm was fabricated by simultaneously feeding Fe and S sources into the MFC anode. This bioanode was then reversed as the biocathode to treat Cr(vi)-containing wastewater in a MFC. The MFC obtained the highest power density (40.75 ± 0.73 mW m-2) and Cr(vi) removal rate (3.99 ± 0.08 mg L-1 h-1), which were 1.31 and 2.00 times those of the control, respectively. The MFC also maintained high stability for Cr(vi) removal in three consecutive cycles. These improvements were due to synergistic effects of nano-FeS with excellent properties and microorganisms in the biocathode. The mechanisms were: (1) the accelerated electron transfer mediated by nano-FeS 'electron bridges' strengthened bioelectrochemical reactions, firstly realizing deep reduction of Cr(vi) to Cr(0) and thus effectively alleviating cathode passivation; (2) nano-FeS as 'armor' layers improved cellular viability and extracellular polymeric substance secretion; (3) the biofilm selectively enriched a diversity of bifunctional bacteria for electrochemical activity and Cr(vi) removal. This study provides a new strategy to obtain electrode biofilms for sustainable treatment of heavy metal wastewater.

[Engineering and process management-based design of Comprehensive Biotechnology Experiment course].

Based on the demand of enterprise talents and the characteristics of manufacturing process management in biotechnology, in order to make the students acquire the ability to solve complex engineering problems in the production process, we developed a "Comprehensive Biotechnology Experiment" course, where two-step enzymatic production of l-aspartate and l-alanine were the key processes. In this course, we drew lessons from the site management of the production enterprise, performed the experimental operation mode of four shifts and three operations. The content of this course includes principles, methods and experimental techniques of several core curricula and the site management mode of enterprises. As to the evaluation, the summary of the experimental staff's handover records and the content of teamwork were examined and scored. Through teaching practice and continuous improvement, we developed a complete experimental teaching process and assessment mechanism. Overall, the Comprehensive Biotechnology Experiment course achieved good teaching effect, which may serve as a reference to promote the development of experimental teaching of biotechnology.

The rapid high-throughput screening of ω-transaminases via a colorimetric method using aliphatic α-diketones as amino acceptors.

ω-Transaminases (ω-TAs) are widely available for the production of chiral amines and unnatural amino acids. Herein, a rapid spectrophotometric method was developed for screening ω-TAs based on the colored products that can be generated from transamination reactions between aliphatic α-diketones and amino donors catalyzed by ω-TAs. The possible mechanism of the formation of the colored product was investigated according to LC-Q-TOF-MS analysis. Among seven diketones, 2,3-butanedione was selected as the most suitable amino acceptor for colorimetric screening of ω-TAs with high efficiency, high sensitivity, and low background interference. Meanwhile, the absorbance of the colored product generated by 2,3-butanedione catalyzed by ω-TAs in this method was linearly correlated with the results by HPLC analysis. This method was also confirmed to effectively screen ω-TA mutants with high activity towards isopropylamine.

Screening UDP-Glycosyltransferases for Effectively Transforming Stevia Glycosides: Enzymatic Synthesis of Glucosylated Derivatives of Rubusoside.

Five plant-derived uridine diphosphate glycosyltransferases (UGTs) that catalyzed the glucosylation of stevia glycosides (SGs) were uncovered as the result of sequence mining considering the catalytic residues and conserved motifs of the known UGTs. Thereinto, LbUGT from Lycium barbarum with high activity toward rubusoside has been enzymatically characterized. The recombinant LbUGT was demonstrated to catalyze the ß-1,6-glucosylation at C19 of rubusoside, producing a monoglucosyl derivative 13-[(O-ß-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(6-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) ester], which was then submitted to a ß-1,2-glucosylation by LbUGT, resulting in a diglucosyl derivative 13-[(O-ß-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(2-O-ß-d-glucopyranosyl-6-O-ß-d-glucopyranosyl-ß-d-glucopyranosyl) ester]. The di-glycosylated product of rubusoside showed an obvious increase in sweetness intensity (134 times sweeter than 5% sucrose) and almost eliminated the unpleasant bitter taste. This work will provide a reference for the taste improvement of SGs.

Efficient Production of 2-O-α-D-Glucosyl Glycerol Catalyzed by an Engineered Sucrose Phosphorylase from Bifidobacterium longum.

2-O-α-D-Glucosyl glycerol (2-αGG) can be used as a multipurpose anti-aging, cell-stimulating, and skin moisturizing agent in the cosmetic industry. Sucrose phosphorylase (SPase) has been widely used in the production of 2-αGG. In this paper, the gene encoding sucrose phosphorylase from Bifidobacterium longum (BlSP) was inserted into pRSF-Duet-1 to construct the recombinant plasmid pRSF-BlSP and was functionally expressed in E. coli BL21(DE3) to be used as a biocatalyst for the synthesis of 2-αGG firstly. The mutations of BlSP were carried out based on alanine scanning, and a positive mutant G293A with a 50% increase in activity for 2-αGG production was identified. Mutant G293A has less Km and bigger kcat/Km towards glycerol than the parental BlSP. Subsequently, the production of 177.6 g/L 2-αGG was attained from 1 M sucrose and 1.2 M glycerol catalyzed by 17 mg/mL G293A mutant. This study indicated that BlSP has good potential in the production of 2-αGG.

Dissolution behavior of arabinoxylan from sugarcane bagasse in tetrabutylammonium hydroxide aqueous solution.

Arabinoxylan is one of the main components of xylan-rich hemicellulose of sugarcane bagasse. The study on the dissolution behavior of arabinoxylan from sugarcane bagasse (AXSB) is beneficial to its efficient utilization. The dissolution behavior of AXSB in a 50% TBAH aqueous solution was investigated by small angle X-ray scattering and rheological methods. SAXS analysis showed that the radius of gyration (Rg) of AXSB is between 8.5 nm and 21.6 nm, and Rg has a larger value with the rising AXSB concentration. Rheological measurements showed that AXSB is completely dissolved in TBAH aqueous solution at low concentration, aggregating after reaching a certain concentration. The estimated critical concentration is approximately 0.033 g mL-1. The rheological curves at the high concentration indicated shear thinning behavior, causing the failure of the Cox-Merz rule. The storage modulus grows gradually with the increasing AXSB concentration, inferring the probable formation of AXSB aggregation in TBAH aqueous solution.

N-acyl-homoserine lactones in extracellular polymeric substances from sludge for enhanced chloramphenicol-degrading anode biofilm formation in microbial fuel cells.

Exploring an efficient acclimation strategy to obtain robust bioanodes is of practical significance for antibiotic wastewater treatment by bioelectrochemical systems (BESs). This study investigated the effects of two acclimation conditions on chloramphenicol (CAP)-degrading anode biofilm formation in microbial fuel cells (MFCs). The one was continuously added the extracellular polymeric substances (EPS) extracted from anaerobic sludge and increasing concentrations of CAP after the first start-up phase, while the other was added the EPS-1 (N-acyl-homoserine lactones, namely AHLs were extracted from the EPS) at the same conditions. The results demonstrated that AHLs in the sludge EPS played a crucial role for enhanced CAP-degrading anode biofilm formation in MFCs. The AHL-regulation could not only maintain stable voltage outputs but also significantly accelerate CAP removal in the EPS MFC. The maximum voltage of 653.83 mV and CAP removal rate of 1.21 ± 0.05 mg/L·h were attained from the EPS MFC at 30 mg/L of CAP, which were 0.84 and 1.57 times higher than those from the EPS-1 MFC, respectively. These improvements were largely caused by the thick and 3D structured biofilm, strong and homogeneous cell viability throughout the biofilm, and high protein/polysaccharide ratio along with more conductive contents in the biofilm EPS. Additionally, AHLs facilitated the formation of a biofilm with rich biodiversity and balanced bacterial proportions, leading to more beneficial mutualism among different functional bacteria. More bi-functional bacteria (for electricity generation and antibiotic resistance/degradation) were specifically enriched by AHLs as well. These findings provide quorum sensing theoretical knowledge and practical instruction for rapid antibiotic-degrading electrode biofilm acclimation in BESs.

Biocatalytic synthesis of 2-O-α-D-glucopyranosyl-L-ascorbic acid using an extracellular expressed α-glucosidase from Oryza sativa.

BACKGROUND: 2-O-α-D-Glucopyranosyl-L-ascorbic acid (AA-2G) is an important derivative of L-ascorbic acid (L-AA), which has the distinct advantages of non-reducibility, antioxidation, and reproducible decomposition into L-AA and glucose. Enzymatic synthesis is a preferred method for AA-2G production over alternative chemical synthesis owing to the regioselective glycosylation reaction. α-Glucosidase, an enzyme classed into O-glycoside hydrolases, might be used in glycosylation reactions to synthesize AA-2G. MAIN METHODS AND MAJOR RESULTS: Here, an α-glucosidase from Oryza sativa was heterologously produced in Pichia pastoris GS115 and used for biosynthesis of AA-2G with few intermediates and byproducts. The extracellular recombinant α-glucosidase (rAGL) reached 9.11 U mL-1 after fed-batch cultivation for 102 h in a 5 L fermenter. The specific activity of purified rAGL is 49.83 U mg-1 at 37°C and pH 4.0. The optimal temperature of rAGL was 65°C, and it was stable below 55°C. rAGL was active over the range of pH 3.0-7.0, with the maximal activity at pH 4.0. Under the condition of 37°C, pH 4.0, equimolar maltose and ascorbic acid sodium salt, 8.7 ± 0.4 g L-1  of AA-2G was synthesized by rAGL. CONCLUSIONS AND IMPLICATIONS: The production of rAGL in P. pastoris was proved to be beneficial in providing enough enzyme and promoting biocatalytic synthesis of AA-2G. These studies lay the basis for the industrial application of α-glucosidase.

Identification, Characterization, and Site-Specific Mutagenesis of a Thermostable ω-Transaminase from Chloroflexi bacterium.

In the present study, we have identified an ω-transaminase (ω-TA) from Chloroflexi bacterium from the genome database by using two ω-TA sequences (ATA117 Arrmut11 from Arthrobacter sp. KNK168 and amine transaminase from Aspergillus terreus NIH2624) as templates in a BLASTP search and motif sequence alignment. The protein sequence of the ω-TA from C. bacterium (CbTA) shows 38% sequence identity to that of ATA117 Arrmut11. The gene sequence of CbTA was inserted into pRSF-Duet1 and functionally expressed in Escherichia coli BL21(DE3). The results showed that the recombinant CbTA has a specific activity of 1.19 U/mg for (R)-α-methylbenzylamine [(R)-MBA] at pH 8.5 and 45 °C. The substrate acceptability test showed that CbTA has significant reactivity to aromatic amino donors and amino receptors. More importantly, CbTA also exhibited good affinity toward some cyclic substrates. The homology model of CbTA was built by Discovery Studio, and docking was performed to describe the relative activity toward some substrates. CbTA evolved by site-specific mutagenesis and found that the Q192G mutant increased the activity to (R)-MBA by around 9.8-fold. The Q192G mutant was then used to convert two cyclic ketones, N-Boc-3-pyrrolidinone and N-Boc-3-piperidone, and both the conversions were obviously improved compared to that of the parental CbTA.

Effects of granular activated carbon and temperature on the viscosity and methane yield of anaerobically digested of corn straw with different dry matter concentrations.

Anaerobic digestion (AD) systems with high substrate concentrations are characterized by high viscosity, which affects material and energy transfer efficiencies, thereby influencing methane production efficiency. In this study, adding granular activated carbon (GAC) and increasing the temperature decreased the viscosity by 4.56-10.19% and 27.13-28.85%, respectively, and improved AD efficiency. Adding GAC and increasing the temperature enhanced the methane yields by 34.37-38.15% and 25.60-28.31%, respectively. Distance-based redundancy analysis showed that the viscosity, temperature, and GAC had the greatest effects on the composition of the microbial community. The dominant bacteria in the medium-temperature AD system at the phylum level belonged to Firmicutes, Bacteroidetes, and Euryarchaeota. In addition to the dominant bacteria in the medium-temperature AD system, the thermophilic phylum Thermotogae was abundant in the high-temperature AD system. Moreover, the relative abundance of Euryarchaeota, which contained most of the methanogens, was higher in the high-temperature AD system than in the medium-temperature AD system.

Expression, Characterization and Its Deinking Potential of a Thermostable Xylanase From Planomicrobium glaciei CHR43.

Genome mining is more and more widely used in identifying new enzymes from database. In the present study, we reported a putative xylanase, Pg-Xyn (WP_053166147.1), which originated from a psychrotolerant strain Planomicrobium glaciei CHR 43, and was identified from Genbank by genome mining. Sequence analysis and homology modeling showed that Pg-Xyn belongs to glycosyl hydrolase family 10. On the basis of heterologous expression in E. coli and biochemical characterization, we found Pg-Xyn was most active at pH 9.0 and 80°C and exhibited good stability from pH 5.0 to 12.0 and below 90°C. Pg-Xyn was slightly activated in the presence of Ca2+ and Mg2+, while it was strongly inhibited by Mn2+. The analysis of hydrolysis products showed that Pg-Xyn was an endo-ß-1,4-xylanase. In addition, Pg-Xyn performed good deinking ability in a paper deinking test. In consideration of its unique properties, Pg-Xyn might be a promising candidate for application in the paper and pulp industries.

Discovering and efficiently promoting the extracellular secretory expression of Thermobacillus sp. ZCTH02-B1 sucrose phosphorylase in Escherichia coli.

Sucrose phosphorylase (SPase, EC2.4.1.7) is a promising transglycosylation biocatalyst used for producing glycosylated compounds that are widely used in the food, cosmetics, and pharmaceutical industries. In this study, a recombinant SPase from the Thermobacillus sp. ZCTH02-B1 (rTSPase), which was previously reported to have high thermostability and the catalytic ability to synthesize ascorbic acid 2-glucoside, was attempted to be extracellularly expressed in Escherichia coli BL21(DE3) by fusion of endogenous osmotically-inducible protein Y. Unexpectedly, the rTSPase itself was produced outside the cells with an underestimated performance, although no typical signal peptide was predicted. Further N- and C-terminal truncation experiments revealed that both termini of rTSPase have an important role in protein folding and enzymatic activity, while its secretion was N-terminus associated. Extracellular protein concentration and rTSPase activity achieved 1.8 mg/mL and 6.2 U/mL after induction of 36 h in a 5-L fermenter. High-level extracellular rTSPase production could also be obtained from E. coli within 24 h by inducing overexpression of D, D-carboxypeptidase for cell lysis.

Enhancing biomethane production and pyrene biodegradation by addition of bio-nano FeS or magnetic carbon during sludge anaerobic digestion.

Pyrene exerts toxic effects on methanogens during anaerobic digestion of sludge, thus affecting the efficiency of sludge treatment. This study evaluated the facilitated direct interspecific electron transfer (DIET) between bacteria and methanogens when bio-nano FeS or magnetic carbon is added into anaerobic reactors. Results showed that adding 200 mg/L bio-nano FeS or magnetic carbon clearly reduced the accumulation of short-chain fatty acids and avoided acidification during 25 days of anaerobic digestion. The methane productions were 98.38 L/kg total solid (TS) and 73.69 L/kg TS in the bio-nano FeS and magnetic carbon systems, respectively, which accelerated methane production by 58.1% and 33.4%, respectively, compared with the control system (40.26 L/kg TS). The pyrene removal rates reached 77.5% and 72.1% in the bio-nano FeS and magnetic carbon systems, whereas it was only 40.8% in the control system. Analysis of microbial community structure revealed that methanogens (e.g. Methanosarcina and Methanosaeta) and extracellular electron-transfer bacteria (e.g. Pseudomonas, Cloastridia, and Synergistetes) were enriched in the reactors added with bio-nano FeS or magnetic carbon. This result indicates that the addition of bio-nano FeS or magnetic carbon may promote the activity and growth of microorganisms to improve the efficiency of methane production and pyrene degradation by enhancing DIET.

Hydrolysis of Corncob Hemicellulose by Solid Acid Sulfated Zirconia and Its Evaluation in Xylitol Production.

Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.33, solid (corncob)-liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis, and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.

Bioconversion of Stevioside to Rebaudioside E Using Glycosyltransferase UGTSL2.

Rebaudioside E, one of the minor components of steviol glycosides, was first isolated and identified from Stevia rebaudiana in 1977. It is a high-intensity sweetener that tastes about 150-200 times sweeter than sucrose and is also a precursor for biosynthesis of rebaudioside D and rebaudioside M, the next-generation Stevia sweeteners. In this work, new unknown steviol glycosides were enzymatically synthesized from stevioside by coupling UDP-glucosyltransferase UGTSL2 from Solanum lycopersicum and sucrose synthase StSUS1 from Solanum tuberosum. Rebaudioside E was speculated to be the main product of glucosylation of the Glc(ß1→C-19) residue of stevioside along with the formation of a (ß1→2) linkage based on the analysis of the regioselectivity and stereoselectivity of UGTSL2, and verified afterwards by LC-MS/MS with standard. In a 20-ml bioconversion reaction of 20 g/l stevioside by UGTSL2 and StSUS1, 15.92 g/l rebaudioside E was produced for 24 h.

A novel core-shell Fe@Co nanoparticles uniformly modified graphite felt cathode (Fe@Co/GF) for efficient bio-electro-Fenton degradation of phenolic compounds.

In this study, a core-shell Fe@Co nanoparticles uniformly modified graphite felt (Fe@Co/GF) was fabricated as the cathode by one-pot self-assembly strategy for the degradation of vanillic acid (VA), syringic acid (SA), and 4-hydroxybenzoic acid (HBA) in the Bio-Electro-Fenton (BEF) system. The Fe@Co/GF cathode showed dual advantages with excellent electrochemical performance and catalytic reactivity not only due to the high electron transfer efficiency but also the synergistic redox cycles between Fe and Co species, both of which significantly enhanced the in situ generation of H2O2 and hydroxyl radicals (OH) to 152.40 µmol/L and 138.48 µmol/L, respectively. In this case, the degradation rates of VA, SA, and HBA reached 100, 94.32, and 100%, respectively, within 22 h. Representatively, VA was degraded and ultimately mineralized via demethylation, decarboxylation and ring-opening reactions. This work provided a promising approach for eliminating typical recalcitrant organic pollutants generated by the pre-treatment of lignocellulose resources.

Coordinated response of Au-NPs/rGO modified electroactive biofilms under phenolic compounds shock: Comprehensive analysis from architecture, composition, and activity.

Electroactive biofilms (EABs) can be integrated with conductive nanomaterials to boost extracellular electron transfer (EET) for achieving efficient waste treatment and energy conversion in bioelectrochemical systems. However, the in situ nanomaterial-modified EABs of mixed-culture, and their response under environmental stress are rarely revealed. Here, two nanocatalyst-decorated EABs were established by self-assembled Au nanoparticles-reduced graphene oxide (Au-NPs/rGO) in mixed-biofilms with different maturities, then their multi-property were analyzed under long-term phenolic shock. Results showed that the power density of Au-NPs/rGO decorated EABs was significantly enhanced by 28.66-42.82% due to the intensified EET pathways inside biofilms. Meanwhile, the electrochemical and catalytic performance of EABs were controllably regulated by 0.3-3.0 g/L phenolic compounds, which, however, resulted in differential alterations in their architecture, composition, and viability. EABs originated with higher maturity displayed more compact structure, lower thickness (110 µm), higher biomass (8.67 mg/cm2) and viability (0.85-0.91), endowing it better antishock ability to phenolic compounds. Phenolic-shock also induced the heterogeneous distribution of extracellular polymeric substances in terms of both spatial and bonding degrees of the decorated EABs, which could be regarded as an active response to strike a balance between self-protection and EET under environmental pressure. Our findings provide a broader understanding of microbe-electrode interactions in the micro-ecology interface and improve their performance in the removal of complex contaminants for sustainable remediation and new-energy development.