Cellulolytic Bacterial Strains Research Articles

Cellulolytic characterization of the rumen-isolated Acinetobacter pittii ROBY and design of a potential controlled-release drug delivery system

A novel cellulolytic bacterial strain, ROBY, was isolated from a bovine rumen sample using the enrichment culture method. This isolate was found to be Acinetobacter pittii, with >99 % similarity according to 16S rRNA gene sequence analysis. The potential use of this strain in combination with doxorubicin (Dox)-integrated cellulose nanoparticles (Dox-CNPs) was evaluated as a proof-of-concept study for the further development of this approach as a novel controlled-release drug delivery strategy. The isolate can utilize CNPs as the sole carbon source for growth and degrade both Dox-CNPs and empty CNPs with high efficiency. Extracellular cellulases isolated from bacteria may also be used to trigger Dox release. The results also demonstrated that the release of Dox into the environment due to nanoparticle degradation in the samples incubated with Dox-CNPs significantly affected bacterial cell viability (∼75 % decrease), proving the release of Dox due to bacterial cellulase activity and suggesting the great potential of this approach for further development.

Isolation and Characterization of Cellulase Producing Bacteria from Soil

The present investigation was undertaken to isolate and Screen the Cellulase Producing Bacteria from Soil. Bacterial cultures were isolated from the soil sample collected from Botanical Garden, Karnatak University Campus, Karnataka, India. Four different substrates like Acacia arabica pod, Bauhinia forficata pod, Cassia surattensis pod and Peltophorum pterocarpum pods (as cellulose substrate) were used in the submerged production medium. A Total of 57 bacterial cultures were isolated based on Morphology and Biochemical characterization. Among all isolated strains, the three cellulolytic bacterial strains, maximum enzyme activity were showed in Bacillus cereus (0.440 IU/ml/min and 0.410 IU/ml/min), followed by Bacillus subtilius (0.357 IU/ml/min) and Bacillus thuringiensis (0.334 IU/ml/min) to the Acacia arabica pod. Acacia arabica pod showed maximum enzyme activity comparatively other pods.

Isolation of an Acidophilic Cellulolytic Bacterial Strain and Its Cellulase Production Characteristics

The aim of the study was to isolate and identify a highly efficient cellulolytic bacteria strain that can be used in acidic environments, and then investigate its cellulase production characteristics for the effective utilization of agricultural waste. For this purpose, we set a series of isolation and screening steps, 21 strains were isolated from soil, and an acidophilic strain labeled as B13-2 with high cellulase production was screened using the Gram’ iodine method and cellulase activity assay; it was identified as Raoultella terrigena. Lastly, the culture conditions such as incubation time, incubation temperature, pH, carbon sources, nitrogen sources, and inoculum size were optimized via single-factor experiments, and on this basis, the cellulase production of strain B13-2 was optimized using response surface methodology with cellulase activity as the optimization goal. The results of the response surface optimization showed that the optimum incubation time is 3.1 days, the optimum temperature is 29.9 °C, the optimum pH is 4.1, and the optimum inoculum size is 1.50%, the cellulase activity reached a maximum of 13.503 U/mL, which was about 140% higher than that before optimization. In particular, strain B13-2 had higher cellulase production when rice straws were used as the natural carbon source. Meanwhile, the SEM pictures demonstrated that the surface of the substrate rice straws in an acidic buffer with strain B13-2 was uneven, with larger holes than in the neutral buffer after incubation. It further proved that this strain has a stronger ability to degrade cellulose under acidic conditions. The B13-2 is a kind of acidophilic cellulolytic bacteria. Therefore, it has the potential to be developed into a silage additive agent and provides a high-quality strain resource for the high-value biotransformation of agricultural waste and lays a certain foundation for the sustainable development of agricultural cultivation.

Isolation and Molecular Identification of Cellulase producing bacteria from soil and litter in Veerakkal forest area, The Western Ghats, India

The cellulolytic bacterial strains were screened from both soil and litter samples in different study sites of Veerakkal forest, Manar beat, The Western Ghats, India. In the current investigation, out of 64 and 48 differentiated total purified isolates, 53 soil isolates and 34 litter isolates were screened based on the CMC method. The percent wise calculation indicated that 82 % were cellulase positive while 18 % were negative in soil isolates. Likewise, 70 % of them were positive while 30 % were negative cellulase strains in litter isolates. The average hydrolysis capacity (HC) values ranged between 1.67 to 3.25 cm. The highly potential cellulolytic bacterial isolates viz. Bacillus thuringiensis, Bacillus licheniformis, Bacillus cereus, Bacillus sporothermodurans, Bacillus circulans, Bacillus albus, Bacillus amyloliquefaciens, Lysinibacillus sphaericus and Bacillus mobilis were identified from soil. Likewise, the litter cellulolytic bacterial species such as Bacillus sp., Lysinibacillus macroides, Bacillus paramycoides, Solibacillus silvestris, Pseudomonas stutzeri, Bacillus toyonensis, Bacillus subtilis, Bacillus pacificus, Bacillus flexus, Bacillus paranthracis and Pseudomonas putida were identified. The cellulolytic bacterial population was higher during the monsoon because of the presence of higher moisture content in leaf litter. However, the cellulolytic bacterial population of soil was higher during the pre-monsoon season because of the continuous breakdown of litter which inhaled more cellulolytic strains in the soil. Finally, it was concluded that corresponding with seasonal changes, the cellulolytic bacterial community also changed and it plays a significant role in the mineralization process.

Identification, characteristics and rice growth promotion of a highly efficient cellulolytic bacterial strain, Cellulomonas iranensis ZJW-6, isolated from paddy soil in central China.

The microbial degradation of lignocellulose is the best way to treat straw, which has a broad application prospect. It is consistent with the idea of agricultural sustainable development and has an important impact on the utilization of biomass resources. To explore and utilize the microbial resources of lignocellulose degradation, 27 lignocellulose degrading strains were screened from 13 regions in China. ZJW-6 was selected because of its 49.6% lignocellulose weight loss rate. According to the theoretical analysis of the experimental results, the following straw degradation conditions were obtained by ZJW-6: nitrogen source input of 8.45 g/L, a pH of 8.57, and a temperature of 31.63°C, the maximum weight loss rate of rice straw could reach 54.8%. It was concluded that ZJW-6 belonged to Cellulomonas iranensis according to 16S rRNA-encoding gene sequence comparison and identification. ZJW-6 is a Gram-positive bacterium that grows slowly and has a small yellowish green colony. To explain the degradation mechanism of lignocellulose, the experiment of enzymatic properties of the strain was prepared and carried out. It was discovered that ZJW-6 has an excellent ability to degrade cellulose, hemicellulose, and lignin, with cellulose and hemicellulose loss rates reaching almost 50% in 4 days and lignin loss rates reaching nearly 30%. Furthermore, ZJW-6 demonstrated lignocellulose degradation under aerobic and anaerobic conditions, indicating the strain's broad application potential. ZJW-6 was found to be more effective than ordinary humic acid in improving rice soil (available phosphorus, available nitrogen, organic matter) and promoting rice growth in a rice pot experiment (increasing root-shoot ratio, root activity, chlorophyll content and net photosynthetic rate). ZJW-6 plays an important role in promoting the development and utilization of straw resources. It has important significance for the advancement of green agriculture.

Influence of the autochthonous cellulolytic bacteria on the domestic compost process improvement.

This work aimed to determine the influence of the inoculation of autochthonous cellulolytic bacteria on the composting process without any modifications of physical or chemical parameters. Bacteria with cellulolytic abilities were isolated from composted material containing food and plant leftovers and identified as Bacillus licheniformis, Bacillus altitudinis, and Lysinibacillus xylanilyticus. The experimental composter containing garden and household wastes was inoculated with bio-vaccine prepared as a mixture of isolated cellulolytic bacterial strains and composted for the next 96 days parallelly to the control composter without the inoculation. During the experiment, changes in temperature, humidity, the content of the humic acids (HAs), organic carbon, nitrogen, and C : N ratio were determined. As the particular microbial groups play a key role in the composting process, the biodiversity of the microorganisms present in the composter as well as the number of psychrophilic, mesophilic, and sporeforming microorganisms, Actinomycetes, and fungi were analyzed. The changes in the abundance of particular bacterial groups were convergent with temperature changes in the temperature of composting material. The composting material inoculated with autochthonous microorganisms was characterized by higher HA content and lower biodiversity. The inoculation with autochthonous microorganisms positively influenced the composting material in the corners for the entire process and in the middle of the container for 61 days. Thus, the effect of inoculation depended on the localization of the process inside the container subjected to biopreparation.

Characterisation of Cellulolytic Bacteria Isolated from Agricultural Soil in Central Lithuania

Characterisation and evaluation of soil bacteria were conducted in order to select the most potent strains that participate in the degradation of cellulose in unique agroecosystem and climatic conditions. Cellulolytic activity of soil bacteria was estimated using qualitative assays such as growth on selective media followed by screening with Congo red, Gram’s iodine solution, confirmation test on Congo red agar, determination of enzyme production, and sugar utilisation pattern. A total of 159 soil cellulolytic bacterial strains were selected based on shape, size, and colony characteristics. According to the results of all three screening assays, sixty-four, thirty-eight and fifty-one isolates were able to degrade at some level of cellulose, respectively. Partial sequencing of the 16S rRNA gene of 64 bacterial strains obtained using sequences retrieved from the databases indicated the presence of cellulolytic bacteria represented by members of the phyla Actinobacteria (48.44%), followed by Firmicutes (32.81%), Proteobacteria (15.62%) and Bacteroidetes (3.13%). Determination of enzyme production showed that fifteen strains possess endoglucanases activity which ranged from 9.09 to 942.41 nanomoles of MUF (4-methylumbelliferone) mL. Likewise, β-glucosidase enzyme activity was determined in 23.4 % of all isolates. The sugar utilisation pattern of soil bacterial strains displayed the different capabilities of growth and utilisation on various carbon sources, which occur in lignocellulosic materials (cellulose, starch) or their hydrolysates (glucose, galactose, fructose, cellobiose, maltose, lactose, sucrose, trehalose).

Indigenous cellulolytic aerobic and facultative anaerobic bacterial community enhanced the composting of rice straw and chicken manure with biochar addition

Microbial degradation of organic matters is crucial during the composting process. In this study, the enhancement of the composting of rice straw and chicken manure with biochar was evaluated by investigating the indigenous cellulolytic bacterial community structure during the composting process. Compared with control treatment, composting with biochar recorded higher temperature (74 °C), longer thermophilic phase (> 50 °C for 18 days) and reduced carbon (19%) with considerable micro- and macronutrients content. The bacterial community succession showed that composting with biochar was dominated by the cellulolytic Thermobifida and Nocardiopsis genera, which play an important role in lignocellulose degradation. Twenty-three cellulolytic bacterial strains were successfully isolated at different phases of the composting with biochar. The 16S rRNA gene sequencing similarity showed that they were related to Bacilluslicheniformis, Bacillussubtilis,Bacillusaerius, and Bacillushaynesii, which were known as cellulolytic bacteria and generally involved in lignocellulose degradation. Of these isolated bacteria, Bacilluslicheniformis, a facultative anaerobe, was the major bacterial strain isolated and demonstrated higher cellulase activities. The increase in temperature and reduction of carbon during the composting with biochar in this study can thus be attributed to the existence of these cellulolytic bacteria identified.

Tropical Cellulolytic Bacteria: Potential Utilization of Sugarcane Bagasse as Low-Cost Carbon Source in Aquaculture.

Sugarcane bagasse (SB), as a major by-product of sugarcane, is one of the most abundant organic matter and characterized by cheap and easily available carbon source in Hainan Island, China. The objective of this study was to isolate tropical cellulolytic bacteria from Hainan Island and demonstrate their prospects of utilization of SB as a low-cost carbon source to greatly reduce the cost of aquaculture. A total of 97 cellulolytic marine bacteria were isolated, of which, 58 cellulolytic marine bacteria displayed the hydrolysis capacity (HC) of more than 1, while 28 cellulolytic marine bacteria displayed more than 2. Of the 28 tropical cellulolytic bacterial strains with HC more than 2, Microbulbifer sp. CFW-C18 and Vibrio sp. MW-M19 exhibited excellent SB decomposition in a small-scale laboratory simulation of shrimp aquaculture, up to 75.31 and 74.35%, respectively, and both of them were safe for shrimps. Meanwhile, both of CFW-C18 and MW-M19 besides displaying low multiple antibiotic resistance (MAR) index, also increased the C/N ratio (CFW-C18: C/N ratio of 14.34; MW-M19: C/N ratio of 14.75) of the small-scale laboratory simulation of shrimp aquaculture by decreasing the nitrogen content after a supplement of SB for 15 days. More importantly, CFW-C18 and MW-M19 displayed a relatively low MAR index, 0.47 and 0.1, respectively, especially MW-M19, with the lowest MAR index (0.1), which was resistant to only three antibiotics, streptomycin, amikacin, and levofloxacin, indicating that this strain was safe and non-drug resistance for further use. Overall, tropical cellulolytic bacteria isolated from Hainan Island, especially CFW-C18 and MW-M19, will provide the proficient candidates as probiotics for further construction of the recirculating aquaculture system based on the supplement of low-cost external carbon source—SB.

A genomic perspective on the potential of termite-associated Cellulosimicrobium cellulans MP1 as producer of plant biomass-acting enzymes and exopolysaccharides.

BackgroundLignocellulose is a renewable and enormous biomass resource, which can be degraded efficiently by a range of cocktails of carbohydrate-active enzymes secreted by termite gut symbiotic bacteria. There is an urgent need to find enzymes with novel characteristics for improving the conversion processes in the production of lignocellulosic-based products. Although various studies dedicated to the genus Cellulosimicrobium as gut symbiont, genetic potential related to plant biomass-acting enzymes and exopolysaccharides production has been fully untapped to date.MethodsThe cellulolytic bacterial strain MP1 was isolated from termite guts and identified to the species level by phenotypic, phylogenetic, and genomic analysis. To further explore genes related to cellulose and hemicellulose degradation, the draft genome of strain MP1 was obtained by using whole-genome sequencing, assembly, and annotation through the Illumina platform. Lignocellulose degrading enzymes and levan production in the liquid medium were also examined to shed light on bacterial activities.ResultsAmong 65 isolates obtained, the strain MP1 was the most efficient cellulase producer with cellulase activity of 0.65 ± 0.02 IU/ml. The whole genome analysis depicted that strain MP1 consists of a circular chromosome that contained 4,580,223 bp with an average GC content of 73.9%. The genome comprises 23 contigs including 67 rRNA genes, three tRNA genes, a single tmRNA gene, and 4,046 protein-coding sequences. In support of the phenotypic identification, the 16S rRNA gene sequence, average nucleotide identity, and whole-genome-based taxonomic analysis demonstrated that the strain MP1 belongs to the species Cellulosimicrobium cellulans. A total of 30 genes related to the degradation of cellulases and hemicellulases were identified in the C. cellulans MP1 genome. Of note, the presence of sacC1-levB-sacC2-ls operon responsible for levan and levan-type fructooligosaccharides biosynthesis was detected in strain MP1 genome, but not with closely related C. cellulans strains, proving this strain to be a potential candidate for further studies. Endoglucanases, exoglucanases, and xylanase were achieved by using cheaply available agro-residues such as rice bran and sugar cane bagasse. The maximum levan production by C. cellulans MP1 was 14.8 ± 1.2 g/l after 20 h of cultivation in media containing 200 g/l sucrose. To the best of our knowledge, the present study is the first genome-based analysis of a Cellulosimicrobium species which focuses on lignocellulosic enzymes and levan biosynthesis, illustrating that the C. cellulans MP1 has a great potential to be an efficient platform for basic research and industrial exploitation.

Endoglucanase activity of cellulolytic bacteria from lake sediments and its application in hydrophyte degradation.

Hydrophytes are plants that grow in or on water. Their overgrowth adversely affects the ecosystem because of crowding out other aquatic organisms and polluting the environment with plant residue. In principle, cellulolytic bacteria can be used to degrade hydrophyte biomass. We here isolated and characterized four cellulolytic bacterial strains from Lake Donghu sediments (Wuhan, China) that are rich in organic matter and plant residues. The isolates (WDHS-01 to 04) represent Bacillus, Micromonospora and Streptomyces genera. The bacteria exhibited pronounced endoglucanase activities (from 0.022 to 0.064U mL-1). They did not extensively degrade the emerged plant Canna indica L. However, in an Hydrilla verticillata (submerged plant) degradation medium, strain WDHS-02 exhibited a high degradation rate (54.91%), endoglucanase activity of 0.35U mL-1 and the conversion rate of cellulose to reducing sugars of 7.15%. Correlation analysis revealed that bacterial endoglucanase activity was significantly correlated with the degradation rate, and acid detergent lignin, ash and cellulose content of the residual H. verticillata powder. In conclusion, the identified bacteria efficiently decomposed submerged plants without the need for acid-base pretreatment. They expand the set of known cellulolytic bacteria and can be used for natural degradation of submerged plants.

Purification and characterization of carboxymethylcellulase from Bacillus pumilus EWBCM1 isolated from earthworm gut (Eudrilus eugeniae)

The present work describes purification and characterization of an extracellular cellulase from a newly isolated cellulolytic bacterial strain Bacillus pumilus EWBCM1. The candidate strain was tested for its abilities to hydrolyze the structural polysaccharides through the depolymerising activities of carboxymethylcellulase. The purification of cellulase was carried out by ammonium sulphate precipitation, DEAE cellulose and sephadex G-100. Purified cellulase was found to be 47.56 fold along with 1.46 U/mg of protein and the molecular weight of cellulase was 47 kDa through SDS-PAGE electrophoresis. The optimum activity of cellulase was registered at pH 10 at 50 °C. In the present study, metal ions inferred the addition of 5 mM CaCl2 (128%) was recorded good activity than the other tested metal ions. Maximum activity of purified cellulase was recorded in 3% of NaCl and 5% of surfactants medium. The bioactive of purified cellulase was carried out with various commercial detergent and antimicrobial activity.

Optimization of Culture Conditions and Reaction Parameters of β-glucosidase From a New Isolate of Bacillus subtilis (B1)

Introduction: The increased need for a considerable β-glucosidase activity, especially in the enzymatic saccharification of cellulose for bioenergy, has strongly stimulated the identification of effective β-glucosidase producing microbes. This study was conducted to optimize culture condition for β-glucosidase production from the identified new isolate of Bacillus subtilis (B1) and to find out an ideal condition for β-glucosidase activity.Materials and Methods: For β-glucosidase production, the bacterium was cultivated in a basal medium. The culture condition was optimized at several pH, different temperatures, varying cultivation periods, and various substrate concentrations. Finally, the activity of the β-glucosidase enzyme was investigated at different incubation periods, pH, temperatures, metal ions, and various percentages of methanol. The activity of β-glucosidase was measured by the capability of crude enzyme to convert pNPG (p-nitrophenyl-β-D glucopyranoside) into yellow product PNP (p-nitrophenol).Results: Cellulolytic bacterial strain B. subtilis (B1) showed high potentiality for β-glucosidase production at a pH of 7.0 after 24 hours incubation at 40°C. The highest level of enzyme production was achieved when 3% of CMC was provided in the culture medium. Optimum reaction conditions for β-glucosidase activity were shown to be 10 minutes, 60°C and at pH 7. Salts like Magnesium Sulfate (MgSO4), Calcium Chloride (CaCl2), and Manganese Sulfate (MnSO4) positively influenced the activity where NaCl and KCl had negative effects. The presence of methanol (80%) appreciably enhanced the activity of enzyme.Conclusions: Complete saccharification of different industrial processes can be augmented by using this novel β-glucosidase produced by B. subtilis strain isolated from effluent of biogas plant.

Characterization and Identification of Cellulose-degrading Bacteria Isolated from a Microbial Fuel Cell Reactor

Electricity can be directly biogenerated by bacteria in a microbial fuel cell (MFC) using many different biodegradable wastes as substrate. When cellulose is used as a substrate, the cellulolytic and electrogenic activities require a microbial consortium for energy generation. In this study, cellulose-degrading bacteria were isolated from an MFC using CMC (carboxymethylcellulose) agar medium and their cellulolytic activity was assessed. Cellulolytic bacteria isolated from the MFC were characterized and identified based on their phenotypic characteristics and analysis of their 16S rRNA genes sequence. Of thirty-two isolates, only ten cellulolytic bacterial strains were successfully isolated from the MFC reactor under aerobic conditions. The bacterial isolates had a cellulolytic index between 3.63 to 8.96 U mL-1. The bacterial strain SAM3a demonstrated high identity (99% via 16S-rRNA sequencing) to Staphylococcus saprophyticus which showed the highest CMCase activity (8.96) 0.34U mL-1). Enterobacter cancerogenus JCT-55 showed the next highest CMCase activity (8.34 ± 0.56 U mL-1); S. epidermidis BAB-2554 showed the lowest CMCase activity (3.63) 0.05 U mL-1). In the MFC, the genus Staphylococcus was found to be the most dominant group of cellulose-degrading bacteria which used rice straw as a carbon source. In this study, Escherichia coli, S. saprophyticus, Enterobacter cancerogenus, S. epidermidis, S. hominis, Bacillus subtilis, L. murinus, S. haemolyticus, S. epidermidis, and S. epidermidis were found to possess cellulolytic activity.

Isolation and Partial Characterisation of Thermophilic Cellulolytic Bacteria from North Malaysian Tropical Mangrove Soil.

This study reports the biodiversity of thermophilic cellulolytic bacterial strains that present in the north Malaysian mangrove ecosystem. Soil samples were collected at the four most northern state of Malaysia (Perak, Pulau Pinang, Kedah and Perlis). The samples obtained were first enriched in nutrient broth at 45°C and 55°C prior culturing in the carboxymethylcellulose (CMC) agar medium. Repeated streaking was performed on the CMC agar to obtain a pure culture of each isolate prior subjecting it to hydrolysis capacity testing. The isolates that showing the cellulolytic zone (halozone) were sent for 16S rRNA sequencing. Total seven isolates (two from Perak, three from Kedah, another two were from Perlis and Penang each) showed halozone. The isolate (KFX-40) from Kedah exhibited highest halozone of 3.42 ± 0.58, meanwhile, the one obtained from Perak (AFZ-0) showed the lowest hydrolysis capacity (2.61 ± 0.10). Based on 16S rRNA sequencing results, 5 isolates (AFY-40, AFZ-0, KFX-40, RFY-20, and PFX-40) were determined to be Anoxybacillus sp. The other two isolates were identified as Bacillus subtilis (KFY-40) and Paenibacillus dendritiformis (KFX-0). Based on growth curve, doubling time of Anoxybacillus sp. UniMAP-KB06 was calculated to be 32.3 min. Optimal cellulose hydrolysis temperature and pH of this strain were determined to be 55°C and 6.0 respectively. Addition of Mg2+ and Ca2+ were found to enhance the cellulase activity while Fe3+ acted as an enzyme inhibitor.

RSM based optimization of nutritional conditions for cellulase mediated Saccharification by Bacillus cereus

BackgroundCellulases are enzyme which have potential applications in various industries. Researchers are looking for potential cellulolytic bacterial strains for industrial exploitation. In this investigation, cellulase production of Bacillus cereus was explored while attacking poplar twigs. The bacterium was isolated from the gut of freshwater fish, Labeo rohita and identified by 16S rRNA gene sequencing technology. Various nutritional conditions were screened and optimized through response surface methodology. Initially, Plackett-Burman design was used for screening purpose and optimization was conducted through Box-Bhenken design.ResultsThe maximum cellulase production occurred at 0.5% yeast extract, 0.09% MgSO4, 0.04% peptone, 2% poplar waste biomass, initial medium pH of 9.0, and inoculum size of 2% v/v at 37 °C with agitation speed of 120 rpm for 24 h of submerged fermentation. The proposed model for optimization of cellulase production was found highly significant. The indigenously produced cellulase enzyme was employed for saccharification purpose at 50 °C for various time periods. Maximum total sugars of 31.42 mg/ml were released after 6 h of incubation at 50 °C.The efficiency of this enzyme was compared with commercial cellulase enzyme revealing significant findings.ConclusionThese results suggested potential utilization of this strain in biofuel industry.

Optimization and molecular identification of novel cellulose degrading bacteria isolated from Egyptian environment.

Cellulase producing bacteria were isolated from both soil and ward poultry, using CMC (carboxymethylcellulose) agar medium and screened by iodine method. Cellulase activity of the isolated bacteria was determined by DNS (dinitrosalicylic) acid method. The highly cellulolytic isolates (BTN7A, BTN7B, BMS4 and SA5) were identified on the basis of Gram staining, morphological cultural characteristics, and biochemical tests. They were also identified with 16S rDNA analysis. The phylogenetic analysis of their 16S rDNA sequence data showed that BTN7B has 99% similarity with Anoxybacillus flavithermus, BMS4 has 99% similarity with Bacillus megaterium, SA5 has 99% homology with Bacillus amyloliquefaciens and BTN7A was 99% similar with Bacillus subtilis. Cellulase production by these strains was optimized by controlling different environmental and nutritional factors such as pH, temperature, incubation period, different volumes of media, aeration rate and carbon source. The cellulase specific activity was calculated in each case. In conclusion four highly cellulolytic bacterial strains were isolated and identified and the optimum conditions for each one for cellulase production were determined. These strains could be used for converting plant waste to more useful compounds.

Isolation of a genetically accessible thermophilic xylan degrading bacterium from compost.

BackgroundDue to the finite nature of global oil resources we are now faced with the challenge of finding renewable resources to produce fuels and chemicals in the future. Lactic acid has great potential as a precursor for the production of bioplastics alternatives to conventional plastics. Efficient lactic acid fermentation from non-food lignocellulosic substrates requires pretreatment and saccharification to generate fermentable sugars. A fermentation process that requires little to no enzyme additions, i.e. consolidated bioprocessing would be preferred and requires lactic acid-producing organisms that have cellulolytic and/or hemicellulolytic activity.ResultsTo obtain candidate production strains we have enriched and isolated facultative anaerobic (hemi) cellulolytic bacterial strains from compost samples. By selecting for growth on both cellulose and xylan, 94 Geobacillus strains were isolated. Subsequent screening for lactic acid production was carried out from C6 and C5 sugar fermentations and a selection of the best lactic acid producers was made. The denitrifying Geobacillus thermodenitrificans T12 was selected for further research and was rendered genetically accessible. In fermentations on a mixture of glucose and xylose, a total of 20.3 g of lactic acid was produced with a yield of 0.94 g product/g sugar consumed. In addition, strain T12 is capable of direct conversion of beech wood xylan to mainly lactic acid in minimal media.ConclusionsWe have demonstrated that G. thermodenitrificans T12 is genetically accessible and produces lactic acid as its main fermentation product on glucose, xylose and a mixture thereof. Strain T12 was additionally used for the direct conversion of xylan to lactic acid. The genetic accessibility of the T12 strain provides a solid basis for the development of this strain into a host for consolidated bioprocessing of biomass to lactic acid.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0618-7) contains supplementary material, which is available to authorized users.

Complete Genome Sequence of Herbinix luporum SD1D, a New Cellulose-Degrading Bacterium Isolated from a Thermophilic Biogas Reactor.

A novel cellulolytic bacterial strain was isolated from an industrial-scale biogas plant. The 16S rRNA gene sequence of the strain SD1D showed 96.4% similarity to Herbinix hemicellulosilytica T3/55T, indicating a novel species within the genus Herbinix (family Lachnospiraceae). Here, the complete genome sequence of Herbinix luporum SD1D is reported.

An isolated Amycolatopsis sp. GDS for cellulase and xylanase production using agricultural waste biomass.

The aim of this study was to evaluate an isolate of Amycolatopsis sp. GDS for cellulase and xylanase production, their characterization, and its application to the preparation of biomass feedstock for ethanol production. A novel potent cellulolytic bacterial strain was isolated and identified as Amycolatopsis sp. GDS. The strain secreted high levels of cellulase and xylanase in the presence of agricultural waste biomass. The enzymes were thermostable and active up to 70°C. Interestingly, the enzymes were expressed well at higher NaCl (up to 2·5moll(-1) ) and ionic liquid (10%) concentrations, so that they could be used during the pretreatment of biomass. Enzyme stability in the presence of organic solvents, surfactants and oxidizing agents was also noted. Crude enzymes from Amycolatopsis sp. GDS resulted in comparable saccharification (60%) of wheat straw to commercial enzymes (64%). The cellulolytic enzymes from Amycolatopsis sp. GDS were stable, expressed well under conditions with various chemicals, and yielded significant amounts of hydrolysates from the biomass. The high bioethanol production using yeast co-cultures with enzymatic hydrolysates highlights the significance of selecting the strain and substrate for biofuel production. This study demonstrates the importance of the isolate Amycolatopsis sp. GDS that secretes high levels of cellulase and hemicellulase by utilizing agricultural waste biomass and its application in the preparation of biomass feedstock and sequential ethanol fermentation.