Clostridium Strains Research Articles

Simultaneous Fermentation of Mixed Sugar by a Newly Isolated Clostridium beijerinckii GSC1

A new wild type solventogenic Clostridium bacterium, which could produce a large amount of solvent from a mixture of 70% glucose and 30% xylose, was isolated. Based on 16S rRNA gene analysis, this strain was identified as Clostridium beijerinckii. Batch fermentations with this strain (C. beijerinckii GSC1) resulted in the production of 19.65 g/L total solvents (Acetone-Butanol-Ethanol), which is 31% higher than that with the typical wild type strain Clostridium acetobutylicum ATCC 824. This new strain utilized glucose and xylose simultaneously without genetic modification. The selectivity of GSC1 for butanol was 81.8%, which is much higher than that of C. acetobutylicum ATCC 824 (68.7%). Simple genetic modification was performed to obtain a more improved performance. The acid production in batch fermentation by C. beijerinckii GSC1_R1 (gene-modified strain) was reduced to 2.6 g/L from 6.02 g/L. The solvent productivity of GSC1_R1 in continuous fermentation was 3.6 g/L/h. These results indicate that the newly isolated strain is very promising and applicable for the production of biobutanol from second-generation biomass owing to the superior performance of the wild type strain.

Enhanced coproduction and trade-off of the hydrogen and butanol in the coupled system of pervaporation and repeated-cycle fixed-bed fermentation

In the study, a coupled system of pervaporation and repeated-cycle fixed bed fermentation with the bagasse as the carrier material was developed. Three repeated cycles of fermentation lasting for 540 h was efficiently carried out to coproduce hydrogen and butanol with the strain Clostridium acetobutylicum. From 1st cycle to 3rd cycle, the average hydrogen productivity and butanol productivity were around 130 mLL−1 h−1 and 0.15 gL−1 h−1, respectively. Average hydrogen yield and butanol yield were around 0.17 Lg−1 and 0.19 gg−1. The hydrogen and butanol production per unit cell weight were 27 Lg−1 and 31 gg−1, which were more than two times of those in a conventional repeated-cycle fermentation. The trade-off and competition between the hydrogen and butanol production was studied and analyzed. Compared with the pervaporation-free fermentation, the hydrogen yield was decreased by 14 % and butanol yield was increased by 27 % in the coupled system. Instantaneous solvent removal from the broth by pervaporation changed probably the metabolic pathway to more butanol production over hydrogen. From 1st cycle to 3rd cycle, the respiration heat generated during each fermentation cycle could cover 45 %, 24 % and 37 % of the total energy requirement of the pervaporation achieving the best use of the energy.

Three Novel Clostridia Isolates Produce n-Caproate and iso-Butyrate from Lactate: Comparative Genomics of Chain-Elongating Bacteria.

The platform chemicals n-caproate and iso-butyrate can be produced by anaerobic fermentation from agro-industrial residues in a process known as microbial chain elongation. Few lactate-consuming chain-elongating species have been isolated and knowledge on their shared genetic features is still limited. Recently we isolated three novel clostridial strains (BL-3, BL-4, and BL-6) that convert lactate to n-caproate and iso-butyrate. Here, we analyzed the genetic background of lactate-based chain elongation in these isolates and other chain-elongating species by comparative genomics. The three strains produced n-caproate, n-butyrate, iso-butyrate, and acetate from lactate, with the highest proportions of n-caproate (18%) for BL-6 and of iso-butyrate (23%) for BL-4 in batch cultivation at pH 5.5. They show high genomic heterogeneity and a relatively small core-genome size. The genomes contain highly conserved genes involved in lactate oxidation, reverse β-oxidation, hydrogen formation and either of two types of energy conservation systems (Rnf and Ech). Including genomes of another eleven experimentally validated chain-elongating strains, we found that the chain elongation-specific core-genome encodes the pathways for reverse β-oxidation, hydrogen formation and energy conservation, while displaying substantial genome heterogeneity. Metabolic features of these isolates are important for biotechnological applications in n-caproate and iso-butyrate production.

Enhanced production of butanol and xylosaccharides from Eucalyptus grandis wood using steam explosion in a semi-continuous pre-pilot reactor

In this work, the co-production of xylosaccharides and butanol from Eucalyptus grandis wood using steam explosion pretreatment in a biorefinery platform was investigated. The effect of different temperature conditions on xylosaccharide production and selectivity as well as enzymatic hydrolysis of pretreated E. grandis substrates was studied using a pre-pilot steam explosion reactor. Under selected conditions (200 °C, 1.5 MPa, 10 min), steam explosion pretreatment led to about 50% xylan recovery as xylooligosaccharides (XOS) and xylose and 80% glucan enzymatic hydrolysis even at high solid loading. A xylosaccharide-rich hydrolysate was effectively separated by ion-exchange and resin treatment, containing mostly xylose and xylobiose as XOS. The fermentation performance of four native butanol-producing strains (Clostridium acetobutylicum DSM 1731, Clostridium beijerinckii DSM 6422, Clostridium beijerinckii DSM 6423 and Clostridium saccaroperbutylacetonicum DSM 14923) were evaluated using semi-synthetic media and enzymatic hydrolysates for butanol production. Results showed that ABE strain Clostridium beijerinckii DSM 6422 and IBE strain Clostridium beijerinckii DSM 6423 are robust native strains for butanol production from lignocellulosic materials. This work highlights a potential integrated biorefinery process for the efficient utilization of E. grandis wood to produce biofuels and biochemicals.

Comparative genomics of Clostridium species associated with vacuum-packed meat spoilage

Bacterial species belonging to the genus Clostridium have been recognized as causative agents of blown pack spoilage (BPS) in vacuum packed meat products. Whole-genome sequencing of six New Zealand psychrotolerant clostridia isolates derived from three meat production animal types and their environments was performed to examine their roles in BPS. Comparative genome analyses have provided insight into the genomic diversity and physiology of these bacteria and divides clostridia into two separate species clusters. BPS-associated clostridia encode a large and diverse spectrum of degradative carbohydrate-active enzymes (CAZymes) that enable them to utilize the intramuscular carbohydrate stores and facilitate sporulation. In total, 516 glycoside hydrolases (GHs), 93 carbohydrate esterases (CEs), 21 polysaccharide lyases (PLs), 434 glycosyl transferases (GTs) and 211 carbohydrate-binding protein modules (CBM) with predicted activities involved in the breakdown and transport of carbohydrates were identified. Clostridia genomes have different patterns of CAZyme families and vary greatly in the number of genes within each CAZy category, suggesting some level of functional redundancy. These results suggest that BPS-associated clostridia occupy similar environmental niches but apply different carbohydrate metabolism strategies to be able to co-exist and cause meat spoilage.

Butyric Acid Generation by Clostridium tyrobutyricum from Low-Moisture Anhydrous Ammonia (LMAA) Pretreated Sweet Sorghum Bagasse.

Sweet sorghum bagasse (SSB) is an under-utilized feedstock for biochemical conversion to biofuels or high value chemicals. One such chemical that can be generated biochemically and applied to a wide array of industries from pharmaceuticals to the production of liquid transportation fuels is butyric acid. This work investigated cultivating the butyric acid producing strain Clostridium tyrobutyricum ATCC 25755 on low-moisture anhydrous ammonia (LMAA) pretreated SSB. Pretreated SSB hydrolysate was detoxified and supplemented with urea for shake flask batch fermentation to show that up to 11.4g/L butyric acid could be produced with a selectivity of 87% compared to other organic acids. Bioreactor fermentation with pH control showed high biomass growth, but a similar output of 11.3g/L butyric acid was achieved. However, the butyric acid productivity increased to 0.251g/L∙hr with a butyric acid yield of 0.29g/g sugar consumed. This butyric acid output represented an 83% theoretical yield. Further improvements in butyric acid titer and yield can be achieved by optimizing nutrient supplementation and incorporating fed-batch fermentation processing of pretreated SSB hydrolysate. Construction of ZGO:Sr NR- and ZGC@PDA NP-driven ratiometric aptasensor for CEA detection.

Laboratory-Based Surveillance of Clostridium difficile Infection in Australian Health Care and Community Settings, 2013 to 2018.

In the early 2000s, a binary toxin (CDT)-producing strain of Clostridium difficile, ribotype 027 (RT027), caused extensive outbreaks of diarrheal disease in North America and Europe. This strain has not become established in Australia, and there is a markedly different repertoire of circulating strains there compared to other regions of the world. The C. difficile Antimicrobial Resistance Surveillance (CDARS) study is a nationwide longitudinal surveillance study of C. difficile infection (CDI) in Australia. Here, we describe the molecular epidemiology of CDI in Australian health care and community settings over the first 5 years of the study, 2013 to 2018. Between 2013 and 2018, 10 diagnostic microbiology laboratories from five states in Australia participated in the CDARS study. From each of five states, one private (representing community) and one public (representing hospitals) laboratory submitted isolates of C. difficile or PCR-positive stool samples during two collection periods per year, February-March (summer/autumn) and August-September (winter/spring). C. difficile was characterized by toxin gene profiling and ribotyping. A total of 1,523 isolates of C. difficile were studied. PCR ribotyping yielded 203 different RTs, the most prevalent being RT014/020 (n = 449; 29.5%). The epidemic CDT+ RT027 (n = 2) and RT078 (n = 6), and the recently described RT251 (n = 10) and RT244 (n = 6) were not common, while RT126 (n = 17) was the most prevalent CDT+ type. A heterogeneous C. difficile population was identified. C. difficile RT014/020 was the most prevalent type found in humans with CDI. Continued surveillance of CDI in Australia remains critical for the detection of emerging strain lineages.

A survey of a blown pack spoilage produced by Clostridium perfringens in vacuum–packaged wurstel

Three hundred Clostridium strains were isolated from spoiled wurstels and were identified by traditional and molecular methods as Clostridium perfringens. The phenotypic characteristics of the strains were studied. All the strains produced acetic and butyric acids and enterotoxin. C. perfringens grew in the spoiled wurstels because it was present in raw meat (Lot 150) at a level of 3.2 log CFU/g due to an unchecked cooling phase that took 28 h to decrease the temperature of the wurstels from 60 to 9–10 °C, which is the lower limit for C. perfringens growth. During the 28 h of cooling, the concentration of C. perfringens increased to 6.5 CFU/g. It was concluded that its presence and the long cooling time were the main factors responsible for the spoilage. Wurstels intentionally made with contaminated meat (3 log CFU/g) but cooled after cooking for 17 h to 9 °C did not support C. perfringens growth; consequently, these wurstels remained unspoiled. The packages of the spoiled wurstels were blown, and the products were soft (soggy), textureless and had the odour of acetic acid, ethanol and sulfur.

Enhancing xylose and glucose utilization as well as solvent production using a simplified three-electrode potentiostat system during Clostridium fermentation.

A simple potentiostat was constructed as a strategy to enhance solvent production in a mediatorless and oxygen-exposed fermentation inoculated with the aerotolerant strain Clostridium sp. C10. Elevated n-butanol and acetone titers were recorded in all fermentations with either glucose or xylose in the presence of electrodes poised at + 500mV (+ 814mV vs SHE) relative to cells plus substrate only controls. Respective butanol titers and volumetric butanol productivities in studies performed with 30g/L glucose or 30g/L xylose were 1.67 and 2.27 times and 1.90 and 6.13 times greater in the presence of electrodes compared to controls. Glucose and xylose utilization in the presence of electrodes was 61 and 125% greater than no-electrode controls, respectively. Increasing substrate concentrations to 60g/L decreased the butanol yields relative to the studies performed at 30g/L. These data suggest that it may be more efficient to alter reactor reduction potential than increase substrate concentration for solvent output during industrial fermentations, which favors higher yield withfew additional inputs.

INTERACTION OF OBLIGATE ANAEROBIC DESTROYER OF SOLID ORGANIC WASTE Clostridium butyricum GMP1 WITH SOLUBLE COMPOUNDS OF TOXIC METALS Cr(VI), Mo(VI) AND W(VI)

Increasing pollution of environment by toxic metals is the urgent problem requiring effective solution worldwide. The goal of the work was to study the dynamics of the interaction of Cr(VI), Mo(VI), W(VI) compounds with obligate anaerobic microorganisms Clostridium butyricum GMP1, which ferment organic compounds with the synthesis of hydrogen. The standard methods were used to determine рН and redox potential (Eh), the gas composition, and the concentration of metals. The application Clostridium butyricum GMP1 was showed to be useful to investigate its interaction with toxic metals. The higher redox potential of metal provided the opportunity for its faster and more effective reduction. The patterns of the reduction of toxic metals Cr(VI), Mo(VI) and W(VI) by obligate anaerobic strain Clostridium butyricum GMP1 were obtained. The experimental data confirmed the thermodynamically calculated correlation between the redox potential of the metal reduction to insoluble form and effectiveness of its removal. Obtained results can serve as the basis for further optimization and development of environmental biotechnologies for wastewater treatment with the simultaneous destruction of solid organic waste and hydrogen synthesis.

Metabolic engineering for the production of butanol, a potential advanced biofuel, from renewable resources.

Butanol is an important chemical and potential fuel. For more than 100 years, acetone-butanol-ethanol (ABE) fermentation of Clostridium strains has been the most successful process for biological butanol production. In recent years, other microbes have been engineered to produce butanol as well, among which Escherichia coli was the best one. Considering the crude oil price fluctuation, minimizing the cost of butanol production is of highest priority for its industrial application. Therefore, using cheaper feedstocks instead of pure sugars is an important project. In this review, we summarized butanol production from different renewable resources, such as industrial and food waste, lignocellulosic biomass, syngas and other renewable resources. This review will present the current progress in this field and provide insights for further engineering efforts on renewable butanol production.

Exploratory Research on the Relationship between Human Gut Microbiota and Portal Hypertension.

Objective The relationship between gut microbiota and portal hypertension remains unclear. We investigated the characteristics of the gut microbiota in portal hypertension patients with esophago-gastric varices and liver cirrhosis. Methods Thirty-six patients (12 patients with portal hypertension, 12 healthy controls, and 12 non-cirrhosis patients) were enrolled in this university hospital study. Intestinal bacteria and statistical analyses were performed up to the genus level using the terminal restriction fragment length polymorphism method targeting 16S ribosomal RNA genes, with diversified regions characterizing each bacterium. Results Levels of Lactobacillales were significantly higher (p=0.045) and those of Clostridium cluster IV significantly lower (p=0.014) in patients with portal hypertension than in other patients. This Clostridium cluster contains many butanoic acid-producing strains, including Ruminococcace and Faecalibacterium prausnitzii. Clostridium cluster IX levels were also significantly lower (p=0.045) in portal hypertension patients than in other patients. There are many strains of Clostridium that produce propionic acid, and the effects on the host and the function of these bacterial species in the human intestine remain unknown. Regarding the Bifidobacterium genus, which is supposed to decrease as a result of cirrhosis, no significant decrease was observed in this study. Conclusion In the present study, we provided information on the characteristics of the gut microbiota of portal hypertension patients with esophago-gastric varices due to liver cirrhosis. In the future, we aim to develop probiotic treatments following further analyses that include the species level, such as the intestinal flora analysis method and next-generation sequencers.

Draft Genome Sequences of Three Clostridia Isolates Involved in Lactate-Based Chain Elongation.

Hitherto, few species have been reported to convert lactate to n-caproate. Here, we report the high-quality draft genomes of three Clostridia strains isolated on lactate as the sole carbon source. The genomes were assembled using a hybrid short- and long-read sequencing approach. The genes involved in lactate-based chain elongation were identified.

The unusual structure of Ruminococcin C1 antimicrobial peptide confers clinical properties

The emergence of superbugs developing resistance to antibiotics and the resurgence of microbial infections have led scientists to start an antimicrobial arms race. In this context, we have previously identified an active RiPP, the Ruminococcin C1, naturally produced by Ruminococcus gnavus E1, a symbiont of the healthy human intestinal microbiota. This RiPP, subclassified as a sactipeptide, requires the host digestive system to become active against pathogenic Clostridia and multidrug-resistant strains. Here we report its unique compact structure on the basis of four intramolecular thioether bridges with reversed stereochemistry introduced posttranslationally by a specific radical-SAM sactisynthase. This structure confers to the Ruminococcin C1 important clinical properties including stability to digestive conditions and physicochemical treatments, a higher affinity for bacteria than simulated intestinal epithelium, a valuable activity at therapeutic doses on a range of clinical pathogens, mediated by energy resources disruption, and finally safety for human gut tissues.

Differences of the structure, succession and function of Clostridial communities between jiupei and pit mud during Luzhou-flavour baijiu fermentation

Clostridia inhabiting in jiupei and pit mud plays key roles in the formation of flavour during the fermentation process of Luzhou-flavour baijiu. However, the differences of Clostridial communities between jiupei and pit mud remains unclear. Here, the species assembly, succession, and metabolic capacity of Clostridial communities between jiupei and pit mud were analysed by high-throughput sequencing and pure culture approaches. The ratio of Clostridial biomass to bacterial biomass in the pit mud was relatively stable (71.5%-91.2%) throughout the fermentation process. However, it varied widely in jiupei (0.9%-36.5%). The dominant Clostridial bacteria in jiupei were Clostridium (19.9%), Sedimentibacter (8.8%), and Hydrogenispora (7.2%), while Hydrogenispora (57.2%), Sedimentibacter (5.4%), and Caproiciproducens (4.9%) dominated in the Clostridial communities in pit mud. The structures of Clostridial community in pit mud and jiupei were significantly different (P=0.001) throughout fermentation. Isolated Clostridial strains showed different metabolic capacities of volatile fatty acids in pure culture. Spatial and temporal heterogeneity of Clostridial communities existed in the baijiu fermentation pit, which was closely related to the main flavour components of Luzhou-flavour baijiu.

Development of optimal steam explosion pretreatment and highly effective cell factory for bioconversion of grain vinegar residue to butanol

BackgroundThe industrial vinegar residue (VR) from solid-state fermentation, mainly cereals and their bran, will be a potential feedstock for future biofuels because of their low cost and easy availability. However, utilization of VR for butanol production has not been as much optimized as other sources of lignocellulose, which mainly stem from two key elements: (i) high biomass recalcitrance to enzymatic sugar release; (ii) lacking of suitable industrial biobutanol production strain. Though steam explosion has been proved effective for bio-refinery, few studies report SE for VR pretreatment. Much of the relevant knowledge remains unknown. Meanwhile, recent efforts on rational metabolic engineering approaches to increase butanol production in Clostridium strain are quite limited. In this study, we assessed the impact of SE pretreatment, enzymatic hydrolysis kinetics, overall sugar recovery and applied atmospheric and room temperature plasma (ARTP) mutant method for the Clostridium strain development to solve the long-standing problem.ResultsSE pretreatment was first performed. At the optimal condition, 29.47% of glucan, 71.62% of xylan and 22.21% of arabinan were depolymerized and obtained in the water extraction. In the sequential enzymatic hydrolysis process, enzymatic hydrolysis rate was increased by 13-fold compared to the VR without pretreatment and 19.60 g glucose, 15.21 g xylose and 5.63 g arabinose can be obtained after the two-step treatment from 100 g VR. Porous properties analysis indicated that steam explosion can effectively generate holes with diameter within 10–20 nm. Statistical analysis proved that enzymatic hydrolysis rate of VR followed the Pseudop-second-order kinetics equation and the relationship between SE severity and enzymatic hydrolysis rate can be well revealed by Boltzmann model. Finally, a superior inhibitor-tolerant strain, Clostridium acetobutylicum Tust-001, was generated with ARTP treatment. The water extraction and enzymolysis liquid gathered were successfully fermented, resulting in butanol titer of 7.98 g/L and 12.59 g/L of ABE.ConclusionsSE proved to be quite effective for VR due to high fermentable sugar recovery and enzymatic hydrolysate fermentability. Inverse strategy employing ARTP and repetitive domestication for strain breeding is quite feasible, providing us with a new tool for solving the problem in the biofuel fields.

Isolation of Clostridium from Yunnan-Tibet hot springs and description of Clostridium thermarum sp. nov. with lignocellulosic ethanol production

Lignocellulose is considered a major source of renewable energy that serve as an alternative to the fossil fuels. Members of the genus Clostridium are some of the many microorganisms that have the ability to degrade lignocellulose efficiently to sugar, which can be further converted to biofuel. In this study, we isolated twelve Clostridium strains from hot spring samples of Yunnan and Tibet, of which isolates SYSU GA15002T and SYSU GA17076 showed low 16S rRNA gene sequence identity profiles to any of the validly named Clostridium strains (<94.0%). Studies using a polyphasic taxonomy approach concluded that the two isolates represent one novel species of the genus Clostridium, for which we propose the name Clostridium thermarum sp. nov., with SYSU GA15002T as the type strain of the species. Isolate SYSU GA15002T has an optimum growth temperature at 45°C. Fermentation of the substrates cellobiose, cellulose, xylan and untreated straw powder by this strain results in the production of ethanol, along with acetate and formate. The complete pathways for the conversion of cellulose and xylan to ethanol is also predicted from the genome of isolate SYSU GA15002T, which revealed a single step conversion of lignocellulosic biomass through consolidated bioprocessing. This paper is a comprehensive study encompassing isolation, polyphasic taxonomy, lignocellulose biodegradation and the genomic information of Clostridium in Yunnan-Tibet hot springs.

Probiotics, Prebiotics, Synbiotics, Postbiotics, and Obesity: Current Evidence, Controversies, and Perspectives.

In this review, we summarize current evidence on gut microbiome and obesity; we discuss the role of probiotics, prebiotics, synbiotics, and postbiotics in obesity prevention and management; and we highlight and analyze main limitations, challenges, and controversies of their use. Overall, the majority of animal studies and meta-analyses of human studies examining the use of probiotics and synbiotics in obesity has shown their beneficial effects on weight reduction and other metabolic parameters via their involvement in gut microbiota modulation. Bifidobacterium and Lactobacillus strains are still the most widely used probiotics in functional foods and dietary supplements, but next generation probiotics, such as Faecalibacterium prausnitzii, Akkermansia muciniphila, or Clostridia strains, have demonstrated promising results. On the contrary, meta-analyses of human studies on the use of prebiotics in obesity have yielded contradictory results. In animal studies, postbiotics, mainly short-chain fatty acids, may increase energy expenditure through induction of thermogenesis in brown adipose tissue as well as browning of the white adipose tissue. The main limitations of studies on biotics in obesity include the paucity of human studies; heterogeneity among the studied subgroups regarding age, gender, and lifestyle; and use of different agents with potential therapeutic effects in different formulations, doses, ratio and different pharmacodynamics/pharmacokinetics. In terms of safety, the supplementation with prebiotics, probiotics, and synbiotics has not been associated with serious adverse effects among immune-competent individuals, with the exception of the use of probiotics and synbiotics in immunocompromised patients. Further large-scale Randomized Controlled Trials (RCTs) in humans are required to evaluate the beneficial properties of probiotics, prebiotics, synbiotics, and postbiotics; their ideal dose; the duration of supplementation; and the durability of their beneficial effects as well as their safety profile in the prevention and management of obesity.

Draft Genome Sequences of Two Clostridium Isolates from the Poultry Gastrointestinal Tract.

Here, we announce the draft genome sequences of two Clostridium strains, C8-1-8 and C2-6-12, isolated from the cecal contents of commercial broiler chickens (in Athens, GA). These strains may represent potentially novel species within the genus Clostridium, and these draft genomes allow further investigation into potential probiotics for poultry.

\u03b2-1,3-Glucanase production as an anti-fungal enzyme by phylogenetically different strains of the genus Clostridium isolated from anoxic soil that underwent biological disinfestation

Biological (or reductive) soil disinfestation (BSD or RSD) is a bioremediation process to control soil-borne plant pathogens using activities of indigenous bacteria in the soil. Three obligate anaerobic bacterial strains (TW1, TW10, and TB10), which were isolated from anoxic soil subjected to BSD treatments, were examined for their abilities to produce anti-fungal enzymes. All strains were affiliated with the different lineages of the genus Clostridium. The three strains decomposed β-1,3-glucans (curdlan and laminarin), and β-1,3-glucanase activities were detected from their culture supernatants with these glucans. The three strains also produced the enzyme with wheat bran as a growth substrate and killed the Fusarium pathogen (Fusarium oxysporum f. sp. spinaciae) in the anaerobic co-incubation conditions. Observation by fluorescence microscopy of the pathogen cells showed that the three strains had degraded the fungal cells in different manners upon co-incubation with wheat bran. When the three strains were cultivated with the dead cells or the cell wall samples prepared from the Fusarium pathogen, strain TW1 utilized these materials as easily decomposable substrates by releasing β-1,3-glucanase. When observed by fluorescence microscopy, it appeared that strain TW1 degraded the mycelial cell wall nearly thoroughly, with the septa remaining as undecomposed luminous rings. In contrast, the other two strains decomposed neither the dead cells nor the cell wall samples directly. The results indicate that the various anaerobic bacteria proliferated in the soil under the BSD treatments should play key roles as an organized bacterial community to eliminate fungal pathogens, namely by release of anti-fungal enzymes with different properties.Key points•Three clostridial strains isolated from BSD-treated soils produced β-1,3-glucanase.•All strains killed the Fusarium pathogen in the anaerobic co-incubation conditions.•One of the strains produced β-1,3-glucanase with the fungal cell wall as a substrate.•The strain degraded the cell wall almost completely, except for the mycelial septa.