Fermentation System Research Articles

Bioconversion of L-Tyrosine into p-Coumaric Acid by Tyrosine Ammonia-Lyase Heterologue of Rhodobacter sphaeroides Produced in Pseudomonas putida KT2440.

p-Coumaric acid (p-CA) is a valuable compound with applications in food additives, cosmetics, and pharmaceuticals. However, traditional production methods are often inefficient and unsustainable. This study focuses on enhancing p-CA production efficiency through the heterologous expression of tyrosine ammonia-lyase (TAL) from Rhodobacter sphaeroides in Pseudomonas putida KT2440. TAL catalyzes the conversion of L-tyrosine into p-CA and ammonia. We engineered P. putida KT2440 to express TAL in a fed-batch fermentation system. Our results demonstrate the following: (i) successful integration of the TAL gene into P. putida KT2440 and (ii) efficient bioconversion of L-tyrosine into p-CA (1381 mg/L) by implementing a pH shift from 7.0 to 8.5 during fed-batch fermentation. This approach highlights the viability of P. putida KT2440 as a host for TAL expression and the successful coupling of fermentation with the pH-shift-mediated bioconversion of L-tyrosine. Our findings underscore the potential of genetically modified P. putida for sustainable p-CA production and encourage further research to optimize bioconversion steps and fermentation conditions.

Investigating drug-gut microbiota interactions: reductive and hydrolytic metabolism of oral glucocorticoids by in vitro artificial gut microbiota

Elucidation of the role of gut microbiota in the metabolism of orally administered drugs may improve therapeutic effectiveness and contribute to the development of personalized medicine. In this study, ten different artificial gut microbiota (AGM), obtained by culturing fecal samples in a continuous fermentation system, were challenged for their metabolizing capacity on a panel of six glucocorticoids selected from either prodrugs or drugs. Data from metabolic stability assays highlighted that, while the hydrolysis-mediated conversion of prodrugs to drugs represented only a minor metabolic pathway, significant differences in the stability of parent compounds and in their conversion rates to multiple reductive metabolites were obtained for the selected drugs. In the latter case, a taxonomic composition-dependent ability to convert parent drugs to metabolites was observed. Indeed, the artificial microbial communities dominated by the genus Bacteroides showed the maximal conversion of parent glucocorticoids to several metabolites. Furthermore, the effect of drugs on AGM was also evaluated through shallow shotgun sequencing and flow cytometry-based total bacterial cell count highlighting that these drugs can affect both the taxonomic composition and growth performances of the human gut microbiota.

Dynamic Programming, Neuro-Dynamic Programming, Rollout Method and Model Predictive Control to Optimal Control of a Fermentation Process

This work presents the use of dynamic programming (DP), neuro-dynamic programming (NDP), rollout algorithm (RA) and model predictive control (MPC) for optimal control of batch cultivation of the yeast Kluyveromyces marxianus var. lactis MC5. DP is a widespread method for solving problems related to optimization and optimal process control. To reduce the “curse of dimensionality”, NDP has been implemented as an alternative. In NDP, a neural network is used to solve the dimensionality problem. A simpler NDP method, called RA, is used to approximate the optimal cost through the cost of a relatively good suboptimal policy, called the baseline policy. RA is a suboptimal method for deterministic and stochastic problems that can be solved by DP. In this paper we also present off-line MPC technique for tracking of constrained fermentation systems and it overcomes the problem by off-line optimizations prior to implementation. MPC is used to provide perturbation feedback and it is developed theoretical on base a controller as an illustration how we can avoid disturbances in the process optimisation. The developed control algorithm-combined NDP and MPC ensures maximum biomass production at the end of the process and feedback during disturbances and process stability and shows that robust stability can be ensured.

Tailoring the properties of carbon molecular sieves membranes for the separation of propionic acid from aqueous solutions

In the fermentative production of propionic acid (PA), the major problem with batch fermentation systems is the strong inhibitory effect of PA on the production yield; one way to increase the yield is the in-situ removal of PA by using pervaporation. Acetic acid (AA) is the most important by-product in the fermentation; therefore, the membrane should be able to remove selectively PA from an aqueous solution containing AA. Considering that PA is more hydrophobic than AA and their kinetic diameter are 0.480 and 0.436 nm respectively, hydrophobic membranes with main pores in the range of around 0.5–0.6 nm with high permeation are required.Supported thin Carbon Molecular Sieve Membranes (CMSM) were prepared by the dip coating a porous alumina support into a solution containing resorcinol phenolic resin as carbon source. The hydrophobicity was obtained by carbonizing the polymer at temperatures higher than 750 °C and adding polyvinyl butyral (PVB) as pore forming agent and carbon contributor. PA with 88 % of purity was obtained by pervaporation of an aqueous solution containing 5 % of PA and 5 % of AA using a CMSM carbonized at 850 °C containing 1 % of PVB in the dipping solution.

Energy efficiency of hydrogen production during dark fermentation

It is widely known that most of the world's energy is produced from non-renewable energy sources such as crude oil and coal. Hydrogen is an ideal fuel candidate with a high energy content and clean combustion product. Biohydrogen is an environmentally friendly, renewable biofuel with high energy density, making it a viable alternative to fossil fuels in the future. At the same time, despite the large number of articles on the intensification of both dark fermentation and anaerobic bioconversion in general, the operating costs of the proposed intensification methods are not well covered in the literature. The goal of the work was to estimate the conversion coefficient of thermal and electrical energy spent on the functioning of the process of dark fermentation of various organic wastes into the energy of produced hydrogen. A block diagram of the energy flows of the dark fermentation system and the structure of the energy consumption of the system were developed. The obtained literature and experimental data suggest that the conversion coefficient of energy into biohydrogen in the process of dark fermentation is less than 1, so to obtain 1 kWh of hydrogen it is necessary to expend more than 1 kWh of energy. At the same time, the use of a vortex layer apparatus for dark fermentation of the food waste model made it possible to increase the energy output of the process by more than 7 times, thereby bringing the values of the conversion coefficients of thermal and electrical energy closer to 1. Despite the fact that the energy efficiency of most known methods for producing hydrogen is higher than the energy efficiency of dark fermentation, it is worth noting that the raw material for producing hydrogen in the dark fermentation process is organic waste, and not high-energy fuel (natural gas, methane, coal) or water in the case of electrolysis. In addition, the use of a vortex layer apparatus for pre-treatment of the dark fermentation substrate made it possible to achieve electricity conversion coefficient values 40% higher than with water electrolysis.

A novel coupled fermentation system for low-molecular-weight xanthan gum with diverse biological activities

Xanthan gum (XG) is a bacterial exopolysaccharide widely used in various industries due to its stability and rheological properties. Low-molecular-weight xanthan gum (LXG) exhibits enhanced properties and broader applications, but current degradation methods are limited. This study introduces an innovative coupled fermentation system for the efficient production of LXG. Endo-xanthanase from Microbacterium sp. XT11 was expressed in Pichia pastoris GS115, exhibiting optimal activity at pH 6.0 and 40 °C, with broad pH tolerance. The optimized coupled fermentation system used bean sprouts juice as nitrogen source, the inoculation quantity of X. campestris: P. pastoris was 1: 3, and the pH was controlled at 6.0. In the bioreactor, the total sugar concentration reached 12.12 g/L, the reducing sugar concentration reached 5.32 g/L, and the endo-xanthanase activity increased to 1150.26 U/L, which were 2.13, 2.3, and 3.71 times higher than those at the shake flask level, respectively. The prepared LXG had a molecular weight of 1093 Da and a monosaccharide ratio of 2.0:1.57:0.89 (glucose, mannose, and glucuronic acid). Bioactivity analysis revealed its antioxidant and prebiotic properties, promoting the growth of beneficial intestinal microbiota and metabolite production. This suggests the potential of LXG as a functional ingredient in intestinal health-focused foods and supplements.

Mechanism of Polygonum hydropiper reducing ethyl carbamate in Chinese rice wine (Huangjiu) brewing

Polygonum hydropiper (PH) is a rich source of active compounds and serves as a pivotal ingredient in Chinese rice wine (Huangjiu) production. This study investigates the impact of PH and Polygonum hydropiper extract (PHE) on ethyl carbamate (EC) production during Huangjiu fermentation. Our findings reveal that PH enhances the relative abundance of Bacillus subtilis in Huangjiu fermentation, thereby facilitating its interaction with Saccharomyces cerevisiae. Furthermore, PH modulates the urea metabolism of S. cerevisiae. In the PH-B. subtilis-S. cerevisiae fermentation system, the expression of DUR1,2 and DUR3 genes in S. cerevisiae is upregulated. This augmentation leads to increased urea uptake and metabolism by S. cerevisiae in the fermentation broth, subsequently reducing the urea concentration in the fermentation medium (The EC content in the CK group was approximately 355.55 % and 356.05 % higher than those in the PH and PHE groups, respectively). Consequently, PH demonstrates promise in reducing the EC concentration of Huangjiu, offering a novel approach to enhance the safety of Huangjiu consumption.

Biochar confers significant microbial resistance to ammonia toxicity in n-caproic acid production

Microbial chain elongation integrating innovative bioconversion technologies with organic waste utilization can transition current energy-intensive n-caproic acid production to sustainable circular bioeconomy systems. However, ammonia-rich waste streams, despite their suitability, pose inhibitory challenges to these bioconversion processes. Herein, biochar was employed as an additive to enhance the activity of chain elongating microbes under ammonia inhibition conditions, with an objective to detail underlying mechanisms of improvements. Biochar addition significantly improved chain elongation performance even under severe ammonia stress (exceeding 8 g N/L), increasing n-caproic acid yields by 40 % to 158 % and reducing lag times by 51 % to 90 %, compared with the best-performing group without biochar addition. The material contribution to n-caproic production reached up to 94.3 % (at 4 g N/L). These enhancements were mainly attributed to the new electron syntrophy induced by biochar, which improved electron transfer system activity and electrical conductivity of the fermentation system. This is further substantiated by increased relative abundances of the genus Sporanaerobacter, electroactive bacteria, and up-regulated direct electron transfer-related genes including conductive pili and c-type cytochrome. This study demonstrates that biochar can confer robust resilience to ammonia toxicity in functional microbes, paving a way for efficient and sustainable n-caproic acid production.

Physical radiation induced the yield of triterpenoids in hypha of Inonotus obliquus to increase

HSD-IO01, a new pure strain of I. obliquus, was isolated and purified from the sclerotium of I. obliquus of Daxing'an Mountains. Physical radiation-assisted liquid fermentation technology was explored to increase the triterpenoids yield of HSD-IO01. In the 100 mL optimized liquid fermentation system, the hypha dry weight of HSD-IO01 was 1.7734 g, and the triterpenoids yield was 43.43 mg. Yields of triterpenoids increased after induction with ultrasound, microwave, or UV light, respectively. Among them, ultrasonic treatment had the most remarkable induction effect. The yield of triterpenoids would be increased to 68.35 mg (57.38 %) when the HSD-IO01 was treated by 100 W ultrasonic for 45 min. Establishing ultrasonic-assisted liquid fermentation technology could further promote the detailed development and comprehensive utilization of I. obliquus resources.

Caproate production from the mixture of corn straw and food waste via chain elongation with reinforcement of biofilm

As a precursor, caproate is widely used in food and medicine for production of various valuable products. From an environmental point of view, caproate production by anaerobic fermentation is a sustainable way. The cost of caproate could be reduced if the wasted biomass is used as substrate. In this study, the caproate production from corn straw and food waste was investigated. Results showed that the sulfuric acid – enzyme method was the optimum approach for hydrolysis of corn straw, and the corresponding glucose concentration was 24.3 g/L. At the optimum condition, the 5-hydroxymethyl furfural (HMF) was found to be the main inhibitor of the hydrolysate, which exhibited inhibitory effect to ethanol and caproate fermentation. Further analysis showed that the inhibition threshold of HMF to Clostridium kluyveri was 1.2 g/L. The formation of biofilm in the fermentation system was found to be an effective way for improving the robustness of cells to inhibitors. The caproate production of 13.5 g/L was obtained when the ethanol and acetate derived from corn straw and food waste was used as substrates. This study cast an insight that it was a promising way for caproate production from the corn straw and food waste.

Bioconversion of ricinoleic acid to (R)-γ-decalactone by Clavispora lusitaniae YJ26 cells in an ionic liquid–containing biphasic fermentation system

Microbial production of chiral γ-decalactone has received considerable attention due to its high market value. However, the inhibition of substrates and products on microorganisms has significantly limited the production of chiral γ-decalactone. In this study, a green biphasic fermentation system containing 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM]PF6) was developed to increase the synthesis of (R)-γ-decalactone from ricinoleic acid catalyzed by Clavispora lusitaniae YJ26. Under optimal conditions, the titer of γ-decalactone obtained using the biphasic system reached 2.04 g/L, which is 2.4 times that of the traditional aqueous fermentation system, and showed high enantioselectivity (e.e.> 99.0%). Fluorescence microscopy and flow cytometry results demonstrated that the addition of [C4MIM]PF6 significantly alleviated the damage of substrate and product to cell membrane and improved cell viability, thus increasing the titer of γ-decalactone. Furthermore, comparative transcriptomic analysis results suggested that the improved mechanism may be attributed to the up-regulation of genes associated with cell membrane component synthesis or cell tolerance enhancement. Overall, the experimental results provide valuable insights into the efficient microbial production of chiral decalactone in an ionic liquids–containing biphasic fermentation system.

CRISPR/Cas9 mediated targeted knock-in of eglA gene to improve endoglucanase activity of Aspergillus fumigatus LMB-35Aa

Bioeconomy goals for using biomass feedstock for biofuels and bio-based production has arisen the demand for fungal strains and enzymes for biomass processing. Despite well-known Trichoderma and Aspergillus commercial strains, continuous bioprospecting has revealed the fungal biodiversity potential for production of biomass degrading enzymes. The strain Aspergillus fumigatus LMB-35Aa has revealed a great potential as source of lignocellulose-degrading enzymes. Nevertheless, genetic improvement should be considered to increase its biotechnological potential. Molecular manipulation based on homologous direct recombination (HDR) in filamentous fungi poses a challenge since its low recombination rate. Currently, CRISPR/Cas9-mediated mutagenesis can enable precise and efficient editing of filamentous fungi genomes. In this study, a CRISPR/Cas9-mediated gene editing strategy for improving endoglucanase activity of A. fumigatus LMB-35Aa strain was successfully used, which constitutes the first report of heterologous cellulase production in filamentous fungi using this technology. For this, eglA gene from A. niger ATCC 10,864 was integrated into conidial melanin pksP gene locus, which facilitated the selection of edited events discerned by the emergence of albino colonies. Heterologous production of the EglA enzyme in a biofilm fermentation system resulted in a 40% improvement in endoglucanase activity of the mutant strain compared to the wild type.

Continuous Liquid-Liquid Extraction of Medium-Chain Fatty Acids from Fermentation Broth Using Hollow-Fiber Membranes.

Medium-chain fatty acids (MCFAs; carbon-lengths: C6-C12) are high-value platform chemicals that serve a variety of industrial applications, including green antimicrobials, food ingredients, animal feed additives, cosmetics, fragrances, pharmaceuticals, and structured lipids. Currently, most MCFAs are produced from palm and coconut oil originating from Southeast Asia and South America. The conventional approach to harvesting palm and coconut fruits causes considerable ecological damage in these regions. Therefore, researchers are developing biological approaches (e.g., precision and open-culture fermentations) to generate MCFAs more sustainably using low-value substrates (e.g., methanol, ethanol, lactate) or organic wastes as feedstock. Microbial chain-elongation (CE) is a rapidly maturing open-culture fermentation platform that converts short-chain fatty acids (SCFAs; carbon lengths: C1-C5) into a subset of these MCFAs at industrially relevant rates. However, continuous in situ extraction of MCFA products is necessary not only to avoid product inhibition but also to facilitate the recovery of MCFAs in a pure and usable form.Liquid-liquid extraction (LLE) using hollow-fiber membranes and targeted extractant mixtures has proven a robust approach to selectively extract MCFA products from fermentation broths containing SCFAs. Here, the application of LLE for continuous MCFA removal is demonstrated using CE as the reference fermentation system and 3% (w/v) trioctylphosphine oxide in mineral oil as the extractant system. Fatty acids ranging from valeric acid (C5) to caprylic acid (C8) are selectively removed from SCFA-containing broths and concentrated to high titers in a semi-batch alkaline stripping solution for downstream processing.

Chitosan and inulin synergized with Lactiplantibacillus plantarum LPP95 to improve the quality characteristics of low-salt pickled tuber mustard

Low-salt pickled vegetables are in line with a healthier diet, yet ensuring consistent quality of such products is challenging. In this study, low-salt tuber mustard pickles fermented with Lactiplantibacillus plantarum LPP95 in the presence of chitosan and inulin were analyzed over a 30-day period, and quality changes were evaluated. Total acid productions along with high bacterial counts (106 CFU/mL) were observed in the initial 20 days during indoor storage temperature, in which the reduced fiber aperture was found significantly lead to an increase in crispness (16.94 ± 1.87 N) and the maintenance of a low nitrate content (1.23 ± 0.01 mg/kg). Moreover, the combined pickling treatment resulted in higher malic acid content, lower tartaric acid content, and a decrease in the content of bitter amino acids (e.g., isoleucine and leucine), thus leading to an increase in the proportion of sweet amino acids. Additionally, combined pickling led to the production of unique volatile flavor compounds, especially the distinct spicy flavor compounds isothiocyanates. Moreover, the combined pickling treatment resulted in an increase in the abundance of Lactiplantibacillus and promoted microbial diversity within the fermentation system. Thus, the synergistic effect among chitosan, inulin, and L. plantarum LPP95 significantly enhanced the quality of pickles. The study offers a promising strategy to standardize the quality of low-salt fermented vegetables.

Unveiling the common laws of extracellular polymeric substances (EPS) properties on short-chain fatty acids production from sludge by EPS disintegration pretreatment

The production of short-chain fatty acids (SCFAs) from sludge is promising, but the efficiency and product quality often vary because of extracellular polymeric substances (EPS) characteristics and pretreatment principles. This study adopted specific EPS disintegration pretreatment to treat different types of sludge. By correlation coefficient matrix analysis and correlation dynamics change resolution, the intrinsic relationships between the nature of EPS and the production of SCFAs from sludge was unveiled. We demonstrate that tight-bound EPS (TB-EPS) is a principal carbon reservoir, positively impacting SCFAs yields, in the fermentation system with EPS as the main fermentation substrate, it can contribute about 29.2 % for SCFAs growth during fermentation. Conversely, TB-EPS exhibits a negative correlation during fermentation due to EPS-SCFAs interconversion, while loosely bound EPS (LB-EPS) correlates positively. Proteins and polysaccharides in TB-EPS, especially proteins, significantly enhance individual SCFAs yields, predominantly acetic, propionic, and isovaleric acids. The findings would provide a theoretical basis for developing pretreatments and process-control technologies aimed at improving SCFAs production efficiency and quality.

Advanced temperature control in ethanol fermentation using a PSO-PID controller with split-range control strategy

Global energy demand is experiencing a notable surge due to growing energy security. Renewable energy sources, like ethanol, are becoming more viable. In the present study, the application of a PSO-PID (Particle Swarm Optimization – Proportional Integral Derivative) controller with a split-range control strategy was suggested for the regulation of temperature within the fermentation system. To optimize performance, a POS-PID controller with a split-range arrangement utilizing two control valves for hot and cold utilities was constructed. The study began by examining the open-loop dynamic response of the system to inlet temperature and concentration disturbances during ethanol production fermentation. Subsequently, a transfer function model was developed through linearization at the steady-state operating point. The split-range controller structure, implemented by optimizing the PSO-PID controller parameters using PSO, effectively demonstrated temperature control in simulations of a nonlinear model. In this investigation, the ethanol fermentation system was modeled as a CSTR using a modified Monod equation for microbial growth kinetics. Various dynamic behavioral disturbances were explored and verified in the model with plant data in this study. The simulation model results were validated through plant data. The proposed method showed superior closed-loop performance with respect to errors, with the actuators proving to be effective than other reported methods for temperature control.

Cassava (Manihot esculenta) Brazilian cultivars have different chemical compositions, present prebiotic potential, and beneficial effects on the colonic microbiota of celiac individuals

The purpose of this study was to investigate the potential prebiotic properties of cassava cultivars from Northeast [Doce mel and Ourinho (OUR)] and South [Baiana, and IPR-Upira (UPI)] of Brazil in in vitro fermentation systems. The cultivars were evaluated for their chemical composition, and, then, two cultivars were selected (OUR and UPI) and subjected to in vitro gastrointestinal digestion to assess the effects on probiotics Lacticaseibacillus casei, Lactobacillus acidophilus, and Bifidobacterium animalis growth, metabolic activity, and prebiotic activity scores. Finally, the impact of cassava cultivars on the fecal microbiota of celiac individuals was evaluated using the 16S rRNA gene. Cassava cultivars have variable amounts of fiber, resistant starch, fructooligosaccharides (FOS), organic acids, phenolic compounds, and sugars, with OUR and UPI cultivars standing out. OUR and UPI cultivars contributed to the increase in the proliferation rates of L. casei (0.04–0.19), L. acidophilus (0.34–0.27), and B. animalis (0.10–0.03), resulting in more significant effects than FOS, an established prebiotic compound. Also, the positive scores of prebiotic activities with probiotic strains indicate OUR and UPI’s ability to stimulate beneficial bacteria while limiting enteric competitors selectively. In addition, OUR and UPI promoted increased relative abundance of Bifidobacteriaceae, Enterococcaceae, and Lactobacillaceae in the fecal microbiota of celiac individuals while decreased Lachnospirales, Bacteroidales, and Oscillospirales. The results show that cassava cultivars caused beneficial changes in the composition and metabolic activity of the human intestinal microbiota of celiacs. OUR and UPI cultivars from the Northeast and South of Brazil could be considered potential prebiotic ingredients for use in the formulation of functional foods and dietary supplements.

Enterococcus avium from a traditional Chinese liquor fermentation system with the potential for the de novo synthesis of GABA

γ-Aminobutyric acid (GABA) is a prevalent nonprotein amino acid with diverse physiological functions, attracting considerable interest in the food industry. However, current GABA-producing strains require glutamate as a substrate for synthesis. Probiotics capable of de novo GABA synthesis using sugars without glutamate are crucial for developing novel foods. This study employed a pH indicator method to selectively screen for GABA-producing bacteria. Nineteen strains with fermentation liquid pH greater than 5 were obtained, all demonstrated the ability to synthesize GABA from Daqu. Among these strains, Enterococcus (E.) avium GL1 stood out for its high GABA production capacity, reaching 9.8 g/L when utilizing glucose for de novo GABA synthesis without monosodium glutamate (MSG). E. avium GL1 exhibited robust viability in challenging environments, maintaining stability in simulated gastric and intestinal fluids. As a potentially probiotic strain, E. avium GL1 achieved remarkable GABA production of 206.84 g/L with a production efficiency of 2.87 g/L/h, facilitated by automatic pH control during fermentation through continuous addition of glucose and MSG addition. This exceptional result represents the highest GABA production reported for E. avium, highlighting its significant potential for the development of innovative functional foods.

A novel strategy combining hydrogenotrophic methanogens' bioaugmentation and biochar biostimulation for simultaneous polycyclic aromatic hydrocarbon biodegradation and bioenergy recovery.

A novel strategy combining bioaugmentation using methanogenic archaea and biostimulation using biochar was proposed for the first time to obtain simultaneous improvement of mixed PAHs' anaerobic biodegradation and bioenergy production. The results showed that the addition of PHAs immediately resulted in inhibition in methane production and accumulation of VFA, indicating that PHAs are more toxic to methanogens than the acetogenic bacteria. The coupling of biochar with hydrogenotrophic methanogen alleviated the inhibitory effects of PAHs, allowing the anaerobic fermentation system to recover its methane production capability rapidly. Compared to the Fe3+ + bioaugmentation group, the biochar + bioaugmentation group exhibited a 7.5% higher restored cumulative methane production. This coupling strategy ultimately facilitated the degradation of most PAHs, achieving a removal rate of over 90%. Moreover, the coupled biochar and bioaugmentation induced significant changes in the archaeal community structure. Direct interspecies electron guilds (i.e., Streptococcus and Methanosarcina) were enriched in the presence of biochar and bioaugmentation, responsible for prominent PAH removal and methane recovery. This study demonstrated the feasibility of simultaneous PAH biodegradation and bioenergy production using electron acceptor and enriched microorganisms.

Effect of lignite addition on hydrogen yield from corn straw

ABSTRACT The hydrogen production by fermentation of simple corn straw is low yield, it is necessary to explore the addition of other substances to increase the hydrogen production of corn straw. Therefore, lignite was used as an additive in this study. The effects of different lignite additions on hydrogen production from corn straw and the changes of substances in the fermentation broth were studied. The results showed that the total gas production of the experimental group with 20% lignite addition was 1.63 mL/g, which was 2.07 times that of the control group without corn straw addition, and the daily hydrogen production peak of the experimental group with 20% lignite addition reached 1.19 mL/g, which was 120.37% higher than that of the control group. The addition of lignite also promoted the degradation of humic acid, benzoic acid, glucose, pyruvic acid, volatile matter and fixed carbon in the reaction system. In summary, lignite has a significant role in promoting hydrogen production from corn straw, and the experimental group with 20% lignite has the best hydrogen production from corn straw. The addition of lignite increased the carbon content in the fermentation system, improved the distribution of organic acids, promoted the consumption of organic matter and fixed carbon, and promoted hydrogen production from corn straw.