基于霍氏肠杆菌强化的光合菌群HAU-M2产氢性能OA

Photo-fermentation hydrogen production from agricultural waste represents a promising approach for sustainable energy generation,yet low conversion efficiency remains a critical challenge limiting its industrial application.This study investigated hydrogen production enhancement by integrating Enterobacter hormaechei into the photosynthetic bacterial community HAU-M1,using corn cob as the substrate to develop an optimized microbial community for improved biohydrogen production.Different volumes of Enterobacter hormaechei were added to HAU-M1 photo-fermentation systems operated at 3000 lux and 30 ℃ for 96 hours.The optimal inoculation ratio was determined by evaluating cumulative hydrogen yield,while mechanistic insights were obtained through systematic monitoring of pH,oxidation-reduction potential(ORP),reducing sugar concentration,and volatile fatty acids(VFAs).Microbial community dynamics were analyzed using 16S rRNA gene sequencing to elucidate the synergistic mechanisms.Results demonstrated that the optimal Enterobacter hormaechei addition at 1.33％of working volume achieved a cumulative hydrogen yield of 63.80 mL/g,representing a 30.47％increase compared to the control group(48.90 mL/g).Kinetic modeling using the modified Gompertz equation showed an excellent fit(R2＞0.97),with maximum hydrogen production potential of 64.16 mL/g and extended fermentation duration(40.99 h).Lag time was reduced from 8.70 to 5.35 h,indicating accelerated metabolic activation.Mechanistic analysis revealed multiple synergistic effects of Enterobacter hormaechei on the photo-fermentation process.While all groups experienced initial acidification,fortified systems exhibited pH recovery after 24 hours,maintaining an optimal range for photosynthetic bacterial activity,whereas the control remained at inhibitory low pH levels.ORP analysis showed that Enterobacter hormaechei maintained deeper reducing conditions favorable for hydrogenase activity.Reducing sugar consumption was accelerated in fortified groups,attributed to biosurfactant production disrupting the hydrophobic lignin barrier and improving enzymatic hydrolysis efficiency.Volatile fatty acids analysis revealed that Enterobacter hormaechei promoted the acetate-type fermentation pathway.The acetate/butyrate ratio reached higher levels during the peak hydrogen production phase(36-48 h)in the fortified system,providing more efficient electron donors for photosynthetic bacteria since the theoretical hydrogen yield from acetate exceeds that from butyrate.This metabolic regulation directly contributed to enhanced hydrogen production efficiency.Microbial community analysis demonstrated significant alterations in community structure.Before fermentation,both HAU-M1 and HAU-M2 were dominated by Rhodobacter species.After 96 hours,the control showed a dramatic decline in photosynthetic bacteria abundance accompanied by proliferation of Clostridium species and lactic acid bacteria,which competed for substrates and produced excessive organic acids.In contrast,the HAU-M2 system maintained higher photosynthetic bacteria abundance with suppressed Clostridium and reduced lactic acid bacteria presence.The fortified system retained 47 shared OTUs before and after fermentation compared to 28 in the control,indicating better preservation of the core microbial community.Enterobacter hormaechei successfully colonized and maintained activity throughout fermentation,as evidenced by sustained high Enterobacteriaceae abundance.The optimized community,designated HAU-M2(HAU-M1 supplemented with 1.33％Enterobacter hormaechei),represents a novel and promising consortium for biohydrogen production.Enterobacter hormaechei functions through multiple mechanisms:consuming residual oxygen to create a favorable anaerobic environment,producing biosurfactants to enhance lignocellulosic substrate degradation,regulating pH and ORP,promoting acetate-type fermentation to provide efficient electron donors,and inhibiting competitive microorganisms.This research offers valuable insights for agricultural waste valorization and sustainable hydrogen production.Future studies should focus on the adaptability of HAU-M2 under continuous fermentation systems,molecular mechanisms underlying the microbial interactions,and process optimization for industrial-scale applications.