Sporolactobacillus Inulinus Research Articles

Sporolactobacillus mangiferae sp. nov., a spore-forming lactic acid bacterium isolated from tree bark in Thailand.

A Gram-stain-positive, facultatively anaerobic and endospore-forming rod-shaped bacterium, designed strain CPB3-1T, was isolated from tree bark. This homofermentative strain produced dl-lactic acid from glucose. It grew at 20-45 °C, pH 4.0-9.5 and in 0-3.0 % (w/v) NaCl. It contained meso-diaminopimelic acid in cell-wall peptidoglycan and had menaquinone with seven isoprene units (MK-7) as the predominant component. The major fatty acid was anteiso-C17 : 0. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, an unknown phospholipid and an unknown lipid. Based on the results of 16S rRNA gene sequence analysis, strain CPB3-1T belonged to the genus Sporolactobacillus and was closely related to Sporolactobacillus kofuensis DSM 11701T and Sporolactobacillus spathodeae BK117-1T (both 96.7 % similarity), Sporolactobacillus inulinus NRIC 1133T and Sporolactobacillus terrae DSM 11697T (both 96.6 % similarity), and Sporolactobacillus shoreicorticis MK21-7T, Sporolactobacillus laevolacticus DSM 442T, Sporolactobacillus shoreae BK92T and Sporolactobacillus pectinivorans GD201205T (all 95.8-96.5 % similarity). The draft genome of strain CPB3-1T contained 2 930 919 bps with 3117 coding genes. The DNA G+C content was 45.1 mol%. The digital DNA-DNA hybridization values between strain CPB3-1T and closely related type strains were 19.2-24.0 %. The average nucleotide identity (84.0-87.6 %) and average amino acid identity (66.5-76.3 %) values were lower than the cut-off values for species delineation. Strain CPB3-1T was clearly distinguished from related Sporolactobacillus species based on its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity and the results of draft genome analysis. Therefore, the strain represents a novel species of the genus Sporolactobacillus, for which the name Sporolactobacillus mangiferae sp. nov. is proposed. The type strain is CPB3-1T (=JCM 35082T=TISTR 10004T).

Biological characterization of D-lactate dehydrogenase responsible for high-yield production of D-phenyllactic acid in Sporolactobacillus inulinus.

PLA (3-D-phenyllactic acid) is an ideal antimicrobial and immune regulatory compound present in honey and fermented foods. Sporolactobacillus inulinus is regarded as a potent D-PLA producer that reduces phenylpyruvate (PPA) with D-lactate dehydrogenases. In this study, PLA was produced by whole-cell bioconversion of S.inulinus ATCC 15538. Three genes encoding D-lactate dehydrogenase (d-ldh1, d-ldh2, and d-ldh3) were cloned and expressed in Escherichia coli BL21 (DE3), and their biochemical and structural properties were characterized. Consequently, a high concentration of pure D-PLA (47 mM) was produced with a high conversion yield of 88%. Among the three enzymes, D-LDH1 was responsible for the efficient conversion of PPA to PLA with kinetic parameters of Km (0.36 mM), kcat (481.10s-1 ), and kcat /Km (1336.39 mM-1 s-1 ). In silico structural analysis and site-directed mutagenesis revealed that the Ile307 in D-LDH1 is a key residue for excellent PPA reduction with low steric hindrance at the substrate entrance. This study highlights that S.inulinus ATCC 15538 is an excellent PLA producer, equipped with a highly specific and efficient D-LDH1 enzyme.

Cost-effective valorization of cassava fibrous waste into enantiomerically pure D-lactic acid: Process engineering and kinetic modelling approach

Cassava fibrous waste (CFW) valorization on the synthesis of D (-) lactic acid (DLA) holds enormous importance, particularly in the production of thermostable and biodegradable polymers. In this study, microbial kinetic modelling was carried out to investigate the dynamics of cassava fibrous waste enzyme hydrolysate (CFWEH) utilization towards DLA production. Designed biomass approach was attempted to evaluate the natural DLA producing organisms, capable of metabolizing CFWEH into optically pure DLA. Sporolactobacillus inulinus (NBRC 13595) was found to be the elite strain, resulting the yield of 99.43 % optically pure DLA using CFWEH-supplemented medium. Yeast extract (2 gL −1 ) was observed to be potential nitrogen source over other complex nitrogen sources for kinetic modelling investigation. Kinetic parameters predicted from the proposed model for DLA production showed maximum specific growth rate, μ max - 0.36 (h −1 ); growth-associated product coefficient ( α = 0 . 47 gg −1 ) and specific productivity ( q P , m a x = 1 . 12 gg −1 h −1 ) respectively. Experimental data of biomass growth, substrate consumption and DLA production with initial sugar concentrations ranging from 20–180 gL −1 was found to be synchronized well with the simulated dynamic profiles. Kinetic investigation reported in this study is a novice attempt enumerating the valorization potential of CFW for the synthesis of value-added products including DLA at commercial scale in near future. • High optical purity (99.43 %) was achieved for D-Lactic Acid. • Valorization potential of cassava fibrous waste was elucidated. • First kind of study on kinetic modelling, utilizing cassava fibrous waste. • Potential scope for techno-economic feasibility of cassava fibrous waste.

Newly-isolated hydrogen-producing bacteria and biohydrogen production by Bacillus coagulans MO11 and Clostridium beijerinckii CN on molasses and agricultural wastewater

Biohydrogen is one of the most potential alternative fuels for the future. Among various substances from agricultural factory waste, molasses and wastewater from ethanol distillation plants are the main focus of this study. To overcome the limitation of bio-H2 production, the direct screening of waste substrates for an efficient producer using co-culture free technique is an interesting choice. Competent species with H2-producing ability and valuable volatile acid such as acetic acid were selected. Several bacteria were isolated and had their species identified by microbial 16SrDNA sequence analysis and phylogenetic analysis by Maximum Likelihood method. Bacillus coaglulans, B. circulans, Sporolactobacillus inulinus, Lactobacillus spp., Pediococcus acidilactici, Paenibacillus thermophilus, Chronobacter sakazaki and Clostridium beijerinckii were found in both reducing-sugar rich waste and wastewater. For bio-H2 application in this criteria, potent natural hydrogen producer B. coagulans MO11 and C. beijerinckii CN were picked to test the growth ability on different substrates (carbon-dioxide, l-arabinose, d-xylose, d-glucose, d-fructose, sucrose, maltose, cellobiose, starch and others). Wastewater from sugarcane factories and other agricultural factories in Thailand were tested for physical and biochemical characteristics which would make them suitable renewable substrates. Among all, Bacillus coagulans MO11 could produce hydrogen gas using molasses and ethanol refinery wastewater effectively (1.634 molH2/mol hexose) as detected by Drager tube, which was the maximum yield in this study. In comparison, the experiment performed by using B. coagulans MO11 and C. beijerinckii CN fed with 40X diluted molasses wastewater showed better production of H2 gas in Clostridium beijerinckii CN during the final 72-hr gas collection (79 mL/L and 125 mL/L respectively). The results pointed in the same direction when replacing 40X diluted molasses with 5X diluted refinery wastewater supplemented with trace elements.

Draft Genome Sequence of Sporolactobacillus inulinus NBRC 111894, Isolated from Kôso, a Japanese Sugar-Vegetable Fermented Beverage.

Sporolactobacillus inulinus NBRC 111894 is a species of endospore-forming lactic acid bacteria isolated from kôso, a Japanese sugar-vegetable fermented beverage. The draft genome sequence of S. inulinus NBRC 111894 is useful for understanding the differences between S. inulinus strains and their conserved characteristics.

Microbial valorization of solid wastes from a recirculating aquaculture system and the relevant microbial functions

This study was performed to establish valorization technology for solid wastes from a seawater recirculating aquaculture system (RAS) by using beneficial microorganisms. An efficient microbial agent (KBM-1) was selected based on the degradation activity of the RAS solid wastes (20% slurry) in a lab-scale reactor system considering the removal rates of chemical oxygen demand, solid material, total nitrogen, ammonium-N, and nitrate-N and the production of organic acids as electron donors for denitrification. The microbial consortium KBM-1 was particularly efficient in the removal of ammonium-N and nitrate-N with removal efficiencies of 42% and 50%, respectively, in eight days and in the rapid production of organic acids (230 mg L−1, 3.5 mM, 0.018 kg m−3 d−1) after two days. There was a concomitant removal of NO3--N (41%, 0.005 kg N m−3 d−1) after two days when a significant production of organic acids occurred. Comamonas sp. was a dominant genus after eight days in all treatments. The level of nitrate-N in the treatments with KBM-1 decreased by 50.4% after eight days, as opposed to that of the control sample (27.7%), indicating the potential denitrification activity of Citrobacter freundii and Comamonas sp. The bioaugmented species (Sporolactobacillus inulinus, Lactobacillus mali, Lactobacillus casei, and Clostridium tyrobutyricum), constituting 41% of the total communities, appeared to facilitate the growth of indigenous microbial communities that were involved in the degradation (hence valorization) of solid wastes (mostly remaining fish feed and fish feces) into simple metabolites (organic acids and inorganic materials such as ammonium, nitrite, nitrate, and CO2). The simultaneous generation of organic acids through the valorization of solid wastes and their subsequent reuse in the denitrification of an RAS biofilter system can provide a significant contribution to the eco-friendly management of RASs and provide meaningful economic merit to the solid wastes of RASs.

Steps Toward High-Performance PLA: Economical Production of d-Lactate Enabled by a Newly Isolated Sporolactobacillus terrae Strain.

Optically pure d-lactate production has received much attention for its critical role in high-performance polylactic acid production. However, the current technology can hardly meet the comprehensive demand of industrialization on final titer, productivity, optical purity, and raw material costs. Here, an efficient d-lactate producer strain, Sporolactobacillus terrae (S. terrae) HKM-1, is isolated for d-lactate production. The strain HKM-1 shows extremely high d-lactate fermentative capability by using peanut meal, soybean meal, or corn steep liquor powder as a sole nitrogen source; the final titers (205.7 g L-1 , 218.9 g L-1 , and 193.9 g L-1 , respectively) and productivities (5.56 g L-1 h-1 , 5.34 g L-1 h-1 , and 3.73 g L-1 h-1 , respectively) of d-lactate reached the highest level ever reported. A comparative genomic analysis between S. terrae HKM-1 and previously reported d-lactate high-producing Sporolactobacillus inulinus (S. inulinus) CASD is conducted. The results show that many unrelated genetic features may contribute to the superior performance in d-lactate production of S. terrae HKM-1. This d-lactate producer HKM-1, along with its fermentation process, is promising for sustainable d-lactate production by using agro-industrial wastes.

Impact of Hydrolysis Methods on the Utilization of Agricultural Residues as Nutrient Source for D-lactic Acid Production by Sporolactobacillus inulinus

d-lactic acid is a building block for heat resistant polylactic acid, a biobased polymer with a high potential. Nevertheless, an economically efficient industrial process for d-lactic acid production still needs to be implemented. Yeast extract is an expensive nutrient source, which is used to fulfill the complex nutritional requirements in lactic acid fermentations. The substitution of yeast extract by cheap alternative nutrient sources is a challenge in many fermentation processes. In this study, chemical and enzymatic hydrolysis techniques for protein rich agricultural residues and their effectiveness are compared, as well as their impact on the d-lactic acid production of Sporolactobacillus inulinus. An efficient substitution of yeast extract could be achieved by a variety of agricultural residues, hydrolysed with 3M H2SO4, demonstrating the much higher versatility and effectiveness of this method compared to enzymatic methods. In a fed-batch experiment with chemically hydrolyzed rapeseed meal and minimal supplementation, a lactic acid titer of 221 g L−1 and an overall productivity of 1.55 g (L h)−1 (96% yield) were obtained.

Relative catalytic efficiencies and transcript levels of three d- and two l-lactate dehydrogenases for optically pure d-lactate production in Sporolactobacillus inulinus.

As the optical purity of the lactate monomer is pivotal for polymerization, the production of optically pure d‐lactate is of significant importance. Sporolactobacillus inulinus YBS1‐5 is a superior optically pure d‐lactate‐producing bacterium. However, little is known about the relationship between lactate dehydrogenases in S. inulinus YBS1‐5 and the optical purity of d‐lactate. Three potential d‐lactate dehydrogenase (D‐LDH1‐3)‐ and two putative l‐lactate dehydrogenase (L‐LDH1‐2)‐encoding genes were cloned from the YBS1‐5 strain and expressed in Escherichia coli D‐LDH1 exhibited the highest catalytic efficiency toward pyruvate, whereas two L‐LDHs showed low catalytic efficiency. Different neutralizers significantly affected the optical purity of d‐lactate produced by strain YBS1‐5 as well as the transcription levels of ldhDs and ldhLs. The high catalytic efficiency of D‐LDH1 and elevated ldhD1 mRNA levels suggest that this enzyme is essential for d‐lactate synthesis in S. inulinus YBS1‐5. The correlation between the optical purity of d‐lactate and transcription levels of ldhL1 in the case of different neutralizers indicate that ldhL1 is a key factor affecting the optical purity of d‐lactate in S. inulinus YBS1‐5.

Lactic acid bacteria and identification with PCR-DGGE

Lactic acid bacteria (LAB) are an important group in the industrially using microorganisms. The first pure cultures of bacteria was "Bacterium lactis" (probably Lactococcus lactis), obtained in 1873 by J. Lister. LAB are Gram-positive, non motile, non spore-forming, except Sporolactobacillus inulinus, catalase negative, microaerophilic or anaerobic microorganisms. LAB can be found in milk and dairy products, plants and human and animal intestinal mucosa. LAB have low Guanine and Cytosine (G+C) ratio.The industrial applications of lactic acid bacteria is considered, it is emphasized that reliable typing methods in strain levels are getting important about both study on cultures used in functional foods and determining the performance of LAB starter cultures. Denaturing Gradient Gel Electrophoresis (DGGE) is the most common technique in molecular fingerprinting culture-independent techniques. The technique is based on the separation of the same length but having different sequences of the Polymerase Chain Reaction (PCR) products.Â

Sodium ions activated phosphofructokinase leading to enhanced D-lactic acid production by Sporolactobacillus inulinus using sodium hydroxide as a neutralizing agent.

Sporolactobacillus inulinus is a superior D-lactic acid-producing bacterium and proposed species for industrial production. The major pathway for D-lactic acid biosynthesis, glycolysis, is mainly regulated via the two irreversible steps catalyzed by the allosteric enzymes, phosphofructokinase (PFK) and pyruvate kinase. The activity level of PFK was significantly consistent with the cell growth and D-lactic acid production, indicating its vital role in control and regulation of glycolysis. In this study, the ATP-dependent PFK from S. inulinus was expressed in Escherichia coli and purified to homogeneity. The PFK was allosterically activated by both GDP and ADP and inhibited by phosphoenolpyruvate; the addition of activators could partly relieve the inhibition by phosphoenolpyruvate. Furthermore, monovalent cations could enhance the activity, and Na+ was the most efficient one. Considering this kind activation, NaOH was investigated as the neutralizer instead of the traditional neutralizer CaCO3. In the early growth stage, the significant accelerated glucose consumption was achieved in the NaOH case probably for the enhanced activity of Na+-activated PFK. Using NaOH as the neutralizer at pH 6.5, the fermentation time was greatly shortened about 22h; simultaneously, the glucose consumption rate and the D-lactic acid productivity were increased by 34 and 17%, respectively. This probably contributed to the increased pH and Na+-promoted activity of PFK. Thus, fermentations by S. inulinus using the NaOH neutralizer provide a green and highly efficient D-lactic acid production with easy subsequent purification.

Nutritional requirements and the impact of yeast extract on thed-lactic acid production by Sporolactobacillus inulinus

For the first time, nutritional requirements including the effects of yeast extract on thed-lactic acid production bySporolactobacillus inulinusare presented.

Betaine Improves Polymer-Grade D-Lactic Acid Production by Sporolactobacillus inulinus Using Ammonia as Green Neutralizer.

The traditional CaCO3-based fermentation process generates huge amount of insoluble CaSO4 waste. To solve this problem, we have developed an efficient and green D-lactic acid fermentation process by using ammonia as neutralizer. The 106.7 g/L of D-lactic acid production and 0.89 g per g of consumed sugar were obtained by Sporolactobacillus inulinus CASD with a high optical purity of 99.7% by adding 100 mg/L betaine in the simple batch fermentation process. The addition of betaine was experimentally proven to protect cell at high concentration of ammonium ion, increase the D-lactate dehydrogenase specific activity and thus promote the production of D-lactic acid.

Combined utilization of nutrients and sugar derived from wheat bran for d-Lactate fermentation by Sporolactobacillus inulinus YBS1-5

To decrease d-Lactate production cost, wheat bran, a low-cost waste of milling industry, was selected as the sole feedstock. First, the nutrients were recovered from wheat bran by acid protease hydrolysis. Then, cellulosic hydrolysates were prepared from protease-treated samples after acid pretreatment and enzymatic saccharification. The combined use of nutrients and hydrolysates as nitrogen and carbon sources for fermentation by S. inulinus YB1-5 resulted in d-Lactate levels of 99.5g/L, with an average production efficiency of 1.94g/L/h and a yield of 0.89g/g glucose. Moreover, fed-batch simultaneous saccharification and fermentation process at 40°C, 20% (w/v) solid loading and 20FPU/g solid cellulase concentration was obtained. d-Lactate concentrations, yield, productivity, and optical purity were 87.3g/L, 0.65g/g glucose, 0.81g/L/h and 99.1%, respectively. This study provided a feasible procedure that can help produce cellulosic d-Lactate using agricultural waste without external nutrient supplementation.

Scopulibacillus daqui sp. nov., a thermophilic bacterium isolated from high temperature daqu

A Gram-stain-positive, facultatively anaerobic, thermophilic bacterium, designated ZQ18-1T, was isolated from a high temperature daqu sample collected from the sesame-flavour liquor-making process. Oval endospores were formed at the centre of cells with swollen sporangia. The isolate was able to grow at temperatures of 20-60 °C (optimum growth at 50 °C), at pH 4-9 (optimum growth at pH 8) and in the presence of 0-10 % (w/v) NaCl (optimum growth with 2 % NaCl). Glucose and galactose were major cell-wall sugars, and meso-diaminopimelic acid was the diagnostic amino acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and three glycolipids. The major cellular fatty acids were anteiso-C17 : 0 and iso-C16 : 0, and the predominant menaquinone was MK-7. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ZQ18-1T was most closely related to Scopulibacillus darangshiensis DLS-06T, Pullulanibacillus pueri YN3T, Tuberibacillus calidus 607T, Pullulanibacillus naganoensis ATCC 53909T, Pullulanibacillus uraniitolerans UG-2T, Sporolactobacillus terrae DSM 11697T and Sporolactobacillus inulinus NRIC 1133T. Strain ZQ18-1T showed low DNA-DNA relatedness (40.7, 23.1, 46.5, 27.2, 45.6, 33.7 and 55.1 %) with the strains mentioned above. Based on morphological characteristics, chemotaxonomic characteristics, DNA-DNA hybridization data and physiological properties, strain ZQ18-1T represents a novel species of the genus Scopulibacillus, for which the name Scopulibacillus daqui sp. nov. is proposed. The type strain is Scopulibacillus daqui ZQ18-1T (=DSM 28236T=CICC 10824T). An emended description of the genus Scopulibacillus is provided.

Enhanced production of optically pure d (–) lactic acid from nutritionally rich Borassus flabellifer sugar and whey protein hydrolysate based–fermentation medium

The aim of this study is to optimize the production of optically pure d (-) lactic acid (DLA) employing a cost-effective production medium. Based on the designed biomass approach, Sporolactobacillus inulinus NBRC 13595 was found to exhibit high DLA titer (19.0 g L-1 ) and optical purity (99.6%). A cost-effective medium was constituted using Palmyra palm jaggery (PJ) from Borassus flabellifer and whey protein hydrolysate (WPH) as carbon and nitrogen sources, respectively. Plackett-Burman design indicated that PJ, WPH, and MnSO4 as significant variables influence DLA production. A rotatable central composite design and response surface methodology were used to optimize the PJ and WPH concentrations. A maximum DLA titer (170.14 g L-1 ) was predicted for 222.24 g L-1 of PJ and 11.99 g L-1 of WPH, respectively. Fermentation experimental results exhibited a maximum DLA titer (189.0 ± 8.53 g L-1 ) and productivity (5.25± 0.24gL-1 H-1 ), which is the highest ever reported for DLA production from a renewable feedstock in the batch process. The present investigation substantiates that the potential application of economically viable raw feedstocks (PJ and WPH) for enhanced DLA production, which is attributed to 2.5-fold reduction in DLA production cost compared with conventional medium.

Terrilactibacillus laevilacticus gen. nov., sp. nov., isolated from soil.

A Gram-stain-positive, catalase-positive, facultatively anaerobic, spore-forming, rod-shaped bacterium, strain NK26-11T, was isolated from soil in Thailand. This strain produced d-lactic acid from glucose homofermentatively, and grew at 20-45 °C and pH 5-8.5. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The major respiratory quinone was menaquinone 7 (MK-7), the DNA G+C content was 42.6 mol%, and the major cellular fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. On the basis of 16S rRNA gene sequences analysis, strain NK26-11T was closely related to Bacillus solimangrovi JCM 18994T (93.89 % 16S rRNA gene sequence similarity), Pullulanibacillus naganoensis LMG 12887T (93.32 %), Sporolactobacillus inulinus NRIC 1133T (92.99 %), Tuberibacillus calidus JCM 13397T (92.98 %) and Thalassobacillus devorans DSM 16966T ( < 90.93 %). Strain NK26-11T could be clearly distinguished from the closely related genera based on phenotypic characteristics and DNA G+C content, and thus represents a novel species of a new genus between the Bacillus and Sporolactobacillus cluster, for which the name Terrilactibacillus laevilacticus gen. nov., sp. nov. is proposed. The type strain of the type species is NK26-11T ( = LMG 27803T = TISTR 2241T = PCU 335T).

D-Lactic acid production by Sporolactobacillus inulinus YBS1-5 with simultaneous utilization of cottonseed meal and corncob residue

d-Lactic acid, is an important organic acid produced from agro-industrial wastes by Sporolactobacillus inulinus YBS1-5 was investigated to reduce the raw material cost of fermentation. The YBS1-5 strain could produce d-lactic acid by using cottonseed meal as the sole nitrogen source. For efficient utilization, the cottonseed meal was enzymatically hydrolyzed and simultaneously utilized during d-lactic acid fermentation. Corncob residues are rich in cellulose and can be enzymatically hydrolyzed without pretreatment. The hydrolysate of this lignocellulosic waste could be utilized by strain YBS1-5 as a carbon source for d-lactic acid production. Under optimal conditions, a high d-lactic acid concentration (107.2g/L) was obtained in 7-L fed-batch fermenter, with an average productivity of 1.19g/L/h and a yield of 0.85g/g glucose. The optical purity of d-lactic acid in the broth was 99.2%. This study presented a new approach for low-cost production of d-lactic acid for an industrial application.

The D-Lactate Dehydrogenase from Sporolactobacillus inulinus Also Possessing Reversible Deamination Activity.

Hydroxyacid dehydrogenases are responsible for the conversion of 2-keto acids to 2-hydroxyacids and have a wide range of biotechnological applications. In this study, a D-lactate dehydrogenase (D-LDH) from a Sporolactobacillus inulinus strain was experimentally verified to have both the D-LDH and glutamate dehydrogenase (GDH) activities (reversible deamination). The catalytic mechanism was demonstrated by identification of key residues from the crystal structure analysis and site-directed mutagenesis. The Arg234 and Gly79 residues of this enzyme play a significant role in both D-LDH and GDH activities. His295 and Phe298 in DLDH744 were identified to be key residues for lactate dehydrogenase (LDH) activity only whereas Tyr101 is a unique residue that is critical for GDH activity. Characterization of the biochemical properties contributes to understanding of the catalytic mechanism of this novel D-lactate dehydrogenase enzyme.

Effect of lignocellulose-derived inhibitors on the growth and D-lactic acid production of Sporolactobacillus inulinus YBS1-5.

The impact of lignocellulose-derived inhibitors on the cell growth and D-lactic production of Sporolactobacillus inulinus YBS1-5 was investigated. At high concentrations, both furans and phenolics, such as furfural, HMF, syringaldehyde and vanillin, affected cell growth and D-lactic acid production and syringaldehyde exhibited the highest. Further experiments showed that only vanillin caused cellular membrane damage. Based on the Biolog approach, in vivo studies on intact S. inulinus cells indicated that phenolics had a stronger inhibitory effect than furan derivatives on the metabolic activity of the concerned substrates related with the key enzymes of D-lactic acid fermentation. The direct in vitro inhibitory effect of the model compounds on the four key enzymes displayed similar patterns. Syringaldehyde was the strongest inhibitor. In general, comparison with published results for other microorganisms indicated that strain YBS1-5 was a robust microorganism against inhibitors of lignocellulose hydrolysate. Notably, in concentrated corn stover hydrolysate, S. inulinus YBS1-5 produced 70.7g/L D-lactic acid, which was 87.7% of the yield from the control experiment. However, the fermentation time was prolonged 36h. In order to improve fermentation rate, a detoxification technology or more robust mutant to phenolics especially syringaldehyde should be developed.