Cellulolytic Strains Research Articles

Molecular characterization of cellulolytic (endo- and exoglucanase) bacteria from the largest mangrove forest (Sundarbans), Bangladesh

PurposeCellulase, due to its massive applicability, has been used in various industrial processes such as biofuels (bioethanol, triphasic biomethanation), agricultural and plant waste management, chiral separation, and ligand binding studies. The finding of a novel cellulase-producing bacterium will benefit the industries, which rely on yeast to produce cellulase in fermentation technology, because bacteria can easily be manipulated and fermented cost-effectively.MethodsCellulase enzyme-secreting bacteria were isolated from different regions of the world’s largest mangrove forests, Sundarbans in Bangladesh. Biochemical, morphological, and 16S rRNA identification protocol was followed to precisely characterize the bacterial strains.ResultWe have determined that the strain T2-D2 (Bacillus sp.), E1-PT (Pseudomonas sp.), and D1-PT (Pseudomonas sp.) showed maximum endoglycolytic and strain C1-BT (Bacillus sp.), E1-BT (Bacillus sp.), and T-4 (E) showed relatively higher exoglycolytic activity during the test. So, it can be easily cultured at a normal temperature (97.7–99.5 °F). On the one hand, T2-D2 (Bacillus sp.) and E1-PT (Pseudomonas sp.) have shown the highest growth rate at pH 7 as it was neither acidic nor basic.ConclusionIt was concluded that the strain T2-D2 (Bacillus sp.) and E1-PT (Pseudomonas sp.) would be our target cellulolytic strains wherein the experimental isolates belonged to the Enterobacteriaceae, Psuedomonacea, Bacillacea, and Morganellacea family.

Enhanced production of cellulase from a novel strain Trichoderma gamsii M501 through response surface methodology and its application in biomass saccharification

Cellulolytic enzymes produced by Trichoderma sp. have attracted interest in converting the biomass to simple sugars in the production of cellulosic ethanol. In this work, a novel cellulolytic strain M501 was isolated and identified as T. gamsii by sequencing the ITS rDNA region. The production of cellulase (CMCase) by T. gamsii M501 was enhanced by employing statistical methods. The strain grown in the optimized production medium composed of mineral salts, microcrystalline cellulose (13.7 g/l), tryptone (4.8 g/l) and trace elements (2 mL/l) at pH 5.5 and 28 °C for 72 h produced a maximum CMCase of 61.3 U/mL. The optimized production medium also showed the other enzyme activity of FPU (2.6 U/mL), β-glucosidase (2.1 U/mL), xylanase (681 U/mL) and β- xylosidase (0.6 U/mL). The crude cellulase cocktail produced by T. gamsii M501 efficiently hydrolyzed alkali pretreated sugarcane bagasse with glucose and xylose yield of 78 % and 74 % respectively at 10 % solid loading. This study is the first of its kind research on biomass saccharification using T. gamsii cellulase cocktail. Therefore, the novel strain T. gamsii M501 would be useful for further development of an enzyme cocktail for cellulosic ethanol production.

Ethanol production by Klebsiella sp. SWET4 using banana peel as feasible substrate

Ethanol has gained its importance as one of the highly demanded biofuels and is being produced from different food crops or food crop wastes after vigorous pretreatment compelling the production process economically incompatible to some extent. The process also becomes non-ecofriendly as the pretreatment process generally produces acid fumes and toxic effluents as well as consumes high energy. In this current study, the potential of the banana peel as a probable substrate for ethanol production was evaluated with the help of logical prediction. Moreover, a single-step ethanol production process was investigated to eliminate hazardous pretreatment processes. A potential bacterial strain SWET4 was isolated from a sewage treatment pond and was identified as a member of the Klebsiella genus by partial sequencing of the 16S rRNA gene. The isolated strain showed ethanol tolerance up to 12% and exhibited its potential as a cellulolytic strain. The bacterial strain SWET4 was found able to ferment banana peel in MSM broth without any other carbon source with a comparatively prolonged lag phase of cellular growth. Trace of ethanol in banana peel fermentation broth of SWET4 was confirmed by high-pressure liquid chromatography. The optimization study for ethanol production enlightened the fact that high temperature and pH supported higher ethanol production. However, due to the growth restriction of the bacterial cell at higher temperatures and pH, only 40 °C and pH 8 were considered optimum. At the optimum substrate concentration (40 g l−1), ethanol concentration was found to be 5.48 g l−1 after 5 days of incubation which summed as a total yield of 0.137 g of ethanol per g of dried banana peel. This current study evaluates the potential of banana peel as a probable substrate for ethanol production and emphasizes on a new possibility of single-step ethanol production without any pretreatment, although metabolic optimization of the strain SWET4 is required to make the process industrially feasible.

Evaluation of Carboxymethyl Cellulase Activity as an Indicator of Active Moulds Inside Foxing Spots on Paper

ABSTRACT Foxing is a special case of fungal deterioration on paper, recognizable by spots of yellowish to brownish colours. Measuring the carboxymethyl cellulase activity (CMCase) by 3,5-dinitrosalicylic method was used to assess the presence of active cellulase inside foxing stains. This was done on foxed paper samples and compared with five fungal strains (belonging to the species Eurotium herbariorum, Talaromyces atroroseus, and Penicillium minioluteum) with cellulolytic capacity, previously identified inside foxing spots, and a highly cellulolytic strain of Trichoderma viride, as a reference. The highest activity of T. viride, expressed as the reducing equivalent glucose released (mg L−1), is achieved at 26°C and in Czapek medium supplemented with carboxymethyl cellulase and sucrose. In the same conditions, for all strains, the activities reached their highest value on the seventh day and then decreased. The method was sufficiently sensitive to indicate the presence of CMCase activity inside foxing spots. These cellulase activities cause paper degradation even after the fungus dies, as the excreted enzymes remain active on the substrate.

Production, purification, and characterization of cellulase from Acinetobacter junii GAC 16.2, a novel cellulolytic gut isolate of Gryllotalpa africana, and its effects on cotton fiber and sawdust

PurposeThe study aims to search for potent cellulase producer from the gut of Gryllotalpa africana as well as to characterize and determine the effect of the purified enzyme on the cellulosic waste materials.MethodsThe potent cellulolytic strain was identified through morphological, biochemical, physiological, and molecular characterization like 16S rRNA and fatty acid methyl ester profile. After the optimization of cellulase production, the enzyme was purified through DEAE-Sepharose column chromatographic separation. The molecular weight of the purified enzyme was determined by SDS-PAGE analysis. The purified enzyme was characterized in terms of its activity and its effect on cotton fiber, and sawdust was also studied.ResultThe selected potent strain GAC 16.2 was identified as Acinetobacter junii that was capable to produce enhanced cellulase (112.38 ± 0.87 U/ml) at standardized optimum fermentation conditions. The molecular weight of the purified enzyme was determined as 55 kDa. The utmost activity of the purified enzyme was detected pH 7.0, temperature 50 °C, and in the presence of metal ions like Mg2+ and Mn2+. The substantive degradation of cotton fiber and sawdust has been observed in a reasonably short period.ConclusionPurified cellulase from the selected isolate A. junii GAC16.2, a gut isolate of G. africana, has the potentiality to degrade cellulosic substances. This property can make the isolate a potent candidature for industrial application, as well as an effective biotechnological tool for environmental monitoring through cellulosic waste management.

Aislamiento e identificación de microorganismos potencialmente amilolíticos y celulolíticos de suelos de humedales de Bogotá

Las amilasas y celulasas de origen microbiano se han utilizado desde hace más de tres décadas en la industria; el aislamiento de cepas microbianas nativas productoras de enzimas es el punto de partida para aprovechar la biodiversidad microbiana para la obtención de enzimas con propiedades para la obtención de nuevos productos en la optimización de procesos industriales. El objetivo de este trabajo, fue aislar, a partir de suelo de cinco humedales en Bogotá, cepas microbianas con capacidad para producir enzimas amilolíticas y celulolíticas. Se realizó la medición de halos de hidrólisis en agar almidón y agar carboximetilcelulosa. Se determinaron las unidades enzimáticas (U/ml/min) por medio de azúcares reductores por la técnica de DNS. Se seleccionaron cuatro cepas de Bacillus subtillis amiloliquefaciens productoras de amilasas con actividades entre 752±33 y 480 ± 35 U/ml/min a 60ºC y cinco cepas celulolíticas identificadas como Bacillus subtillis amiloliquefaciens, Stenotrophomonas nitritireducens y Yersinia massiliensis, capaces de producir celulasas con actividades enzimáticas entre 19.11 ± 2.3 y 13.82 ± 2.5 UA/ml/min a 50ºC. Con estos resultados se demostró que a partir de suelos de humedales, se pueden recuperar microrganismos con capacidad de producción enzimática, como punto de partida para una posterior aplicación en procesos industriales.

Carotenoid-producing yeasts: Identification and Characteristics of Environmental Isolates with a Valuable Extracellular Enzymatic Activity.

Sixteen cold-adapted reddish-pigmented yeast strains were obtained from environmental samples. According to the PCR-based detection of classical yeast markers combined with phylogenetic studies, the yeasts belong mainly to the genera Rhodotorula, Sporobolomyces and Cystobasidium, all within the subphylum Pucciniomycotina. All strains produced carotenoids within a 0.25–10.33 mg/L range under non-optimized conditions. Noteworthily, among them, representatives of the Cystobasidium genus were found; of particular value are the strains C. laryngis and C. psychroaquaticum, poorly described in the literature to date. Interestingly, carotenoid production with representatives of Cystobasidium was improved 1.8- to 10-fold at reduced temperature. As expected, most of the isolated yeasts biosynthesized extracellular lipases, but within them also one proteolytic and four cellulolytic strains were revealed. We succeeded in isolating strain Cystofilobasidium macerans WUT145 with extraordinarily high cellulolytic activity at 22°C (66.23 ± 0.15 µmol/mg protein·min) that is described here for the first time. Consequently, a set of yeasts capable of producing both carotenoids and extracellular enzymes was identified. Taking into account those abilities, the strains might be applicable for a development of carotenoids production on an agro-industrial waste, e.g., lignocellulose.

Symbiotic cellulolytic bacteria from the gut of the subterranean termite Psammotermes hypostoma Desneux and their role in cellulose digestion

The subterranean termite Psammotermes hypostoma Desneux is considered as an important pest that could cause severe damage to buildings, furniture, silos of grain and crops or any material containing cellulose. This species of termites is widespread in Egypt and Africa. The lower termite’s ability to digest cellulose depends on the association of symbiotic organisms gut that digest cellulose (flagellates and bacteria). In this study, 33 different bacterial isolates were obtained from the gut of the termite P. hypostoma which were collected using cellulose traps. Strains were grown on carboxymethylcellulose (CMC) as a sole source of carbon. Cellulolytic strains were isolated in two different cellulose medium (mineral salt medium containing carboxymethylcellulose as the sole carbon source and agar cellulose medium). Five isolates showed significant cellulolytic activity identified by a Congo red assay which gives clear zone. Based on biochemical tests and sequencing of 16s rRNA genes these isolates were identified as Paenibacillus lactis, Lysinibacillus macrolides, Stenotrophomonas maltophilia, Lysinibacillus fusiformis and Bacillus cereus, that deposited in GenBank with accession numbers MG991563, MG991564, MG991565, MG991566 and MG991567, respectively.

Improved cellulase expression in diploid yeast strains enhanced consolidated bioprocessing of pretreated corn residues

In an effort to find a suitable genetic background for efficient cellulolytic secretion, genetically diverse strains were transformed to produce core fungal cellulases namely, β-glucosidase (BGLI), endoglucanase (EGII) and cellobiohydrolase (CBHI) in various combinations and expression configurations. The secreted enzyme activity levels, gene copy number, substrate specificities, as well as hydrolysis and fermentation yields of the transformants were analysed. The effectiveness of the partially cellulolytic yeast transformants to convert two different pre-treated corn residues, namely corn cob and corn husk was then explored. Higher secretion titers were achieved by cellulolytic strains with the YI13 genetic background and cellulolytic transformants produced up to 1.34 fold higher glucose concentrations (g/L) than a control composed of equal amounts of each enzyme type. The transformant co-producing BGLI and EGII in a secreted ratio of 1:15 (cellulase activity unit per gram dry cell weight) converted 56.5% of the cellulose present in corn cob to glucose in hydrolysis experiments and yielded 4.05 g/L ethanol in fermentations. We demonstrate that the choice of optimal genetic background and cellulase activity secretion ratio can improve cellulosic ethanol production by consolidated bioprocessing yeast strains.

Efficient Enzyme-Assisted Extraction and Conversion of Polydatin to Resveratrol From Polygonum cuspidatum Using Thermostable Cellulase and Immobilized β-Glucosidase.

Resveratrol, a bioactive compound in high quantities in Polygonum cuspidatum, has well-known health benefits. However, it mainly exists in its glycosidic form, polydatin, in plants. To increase the production of resveratrol for various uses in medicine, foods, and cosmetics, an efficient deglycosylation technique is needed for converting polydatin into resveratrol. We screened a new cellulolytic strain of Bacillus from herb compost, and we optimized parameters within the fermentation process using response surface methodology with a Box–Behnken design. The yield of cellulase reached 2701.08 U/L, corresponding to values that were 5.4 times as high as those under unoptimized conditions. The Bacillus cellulase possessed good thermostablity and was stable under both acidic and neutral conditions. The cellulase was then used in the pretreatment of P. cuspidatum root. After incubation at 50°C for 4 h with shaking at 150 rpm, the contents of piceid and resveratrol were determined to be 7.60 ± 0.15 and 9.72 ± 0.29 mg/g, respectively. To obtain complete deglycosylation, immobilized β-glucosidase (bgl2238) was added to the cellulase-treated extracts of P. cuspidatum root to convert residual polydatin into resveratrol. After the first cycle, the contents of piceid and resveratrol were determined to be 0 and 13.69 ± 0.30 mg/g, respectively. Moreover, enzyme activity showed little loss during up to 4 consecutive cycles. These results demonstrated that the immobilized β-glucosidase possessed high deglycosylation activity and outstanding operational stability. The mixture of Bacillus cellulase and immobilized bgl2238 appears promising as a means to increase the supply of resveratrol in the medicine market worldwide.

Isolation, growth, enzyme assay and identification via 16S rRNA full sequencing of cellulolytic microbes from Nepal for biofuel production

Abstract With its rich climatic and geographical variance, Nepal harbors a habitat for a diverse set of microbes. This research aims to identify and study the potency of native cellulolytic microbes. Cellulolytic microbes are being used to produce biofuels. The microorganisms were isolated from varied sources and grown in three valid media: Tryptone Soy Broth (TSB), Nutrient Broth (NB) and Gelatin. The findings from the growth quality observations, hydrolysis capacity calculations, and total cellulase assay were used to assess the cellulase enzyme potency of the microbes. Although all three media can be used to study the growth and isolation of the cellulolytic microbes, and different media showed different application potential, Gelatin media may be preferred for screening a large sample size. Hydrolysis capacity in TSB, NB and Gelatin media ranged from 4.0–5.2, 3.8–5.4 and 4.0–5.4 for the bacterial samples and 8.8, 9.0 and 9.2 for 0.1% pure cellulase enzyme, respectively. The results from 16S rRNA full-sequence and cladogram analysis indicate the possibility of a new strain of cellulolytic bacteria. Among the isolated microorganisms, four microbes were discovered close to the Bacillus genus, and one microbe was close to Paenibacillus. The selection of media for isolation and culture of the cellulolytic microbes depends on the researcher’s decision and the availability of the resources. As one of the first studies to identify the native cellulolytic strains of Nepali origin, the study pushes other national and international researchers to consider the divergent climatic conditions of Nepal for potential cellulolytic strains.

MORPHOLOGICAL AND CULTURAL, PHYSIOLOGICAL AND BIOCHEMICAL PECULIARITIES OF MICROMYCETES STRAINS INCLUDING IN THE COMPOSITION OF TRICHODERMA HARZIANUM 128 ASSOCIATION

Objective. Screen the active cellulolytic strains of Trichoderma micromycetes, investigate their morphological and cultural, physiological and biochemical properties for further use in the composting of organic substrates as a straw destroyer.
 Methods. Microbiological, biochemical, statistical.
 Results. 150 isolates of cellulolytic microscopic fungi of the genus Trichoderma were obtained from semi-decomposed straw. Among isolated fungi, the most active influence on the destruction of cellulose is typical for the association of micromycetes Trichoderma sp. 128. The components of the association (Trichoderma sp. 128/1 and Trichoderma sp. 128/2, respectively) differ in their nature of growth in the digest medium, colouring of colonies, and cellulolytic activity. Under simultaneous cultivation of the association components in a medium where the only source of carbon is filter paper or straw, higher effect was observed compared with than their separate cultivation. The selected association provides a degree of straw decomposition of up to 33 % over a period of 21 days, which exceeds the activity of the known cellulolytic strain Trichoderma harzianum F-2455. By morphological and cultural, physiological and biochemical properties, the components of the fungal association have been identified as Trichoderma harzianum 128/1 and T. harzianum 128/2 (association – Trichoderma harzianum 128, respectively). Under the study of virulence of microorganisms on the model of white mice, it was established that the association components are not pathogenic for warm-blooded animals, which allows the association to be used in the production.
 Conclusion. Active cellulolytic association of micromycetes which includes two strains has been selected. The association is identified as Trichoderma harzianum 128. The use of the association of micromycetes can be promising when composting organic matter, in order to accelerate its mineralization.

UTILIZATION OF AGROINDUSTRIAL BY-PRODUCTS AS SUBSTRATE IN ENDOGLUCANASE PRODUCTION BY Streptomyces diastaticus PA-01 UNDER SUBMERGED FERMENTATION

Abstract Endoglucanase production under submerged fermentation was studied using sugarcane bagasse (SCB) and oat bran (OB) as carbon source and corn steep liquor (CSL) as nitrogen source, in different concentrations using factorial design. Streptomyces diastaticus PA-01, isolated from a soil cave in Brazil, was selected as cellulolytic strain. The results after experimental validation showed that a medium containing 2.4% (w/v) SCB and 1.3% (w/v) CSL led to the highest production, 1,180.3 U.L-1 of endoglucanase, after the 5th-day. A good level of endoglucanase (1,039.3 U.L-1) was obtained after the 4th-day when 2.0% (w/v) OB and 1.65% (w/v) CSL were used. The pH and temperature profiles showed thermoacidophilic endoglucanase activity, with 70% of maximum activity at 50oC, after 4 hours of pre-incubation. This is the first report on endoglucanase production by S. diastaticus PA-01 in the presence of SCB and OB. The strong positive effects of some metal ions (Zn2+, Mn2+ and Ba2+) on endoglucanase activity when this strain was grown on OB is an interesting biochemical characteristic for future biotechnological applications.

Study on the Effect of cellulolytic strain MYB3 for Corn Stover Fermentation

The effects of corn stover fermentation with the Bacillus megaterium MYB3 was studied in this paper. The results showed that the decomposition rates of cellulose and hemicellulose were 49.6%, 43.46% after 20 days respectively, after fermentation, pH was changed to 5.68, and adjusted to corn stover initial pH 3 to achieve the purpose of sterilization. The decomposition rate was significantly increased by adding corn flour. After adjusting fermentation composes with the ratio of the corn stove to corn flour was 15 : 1, the decomposition rate of cellulose would be 52.37% for 10 days.

Evolving Microbial Communities in Cellulose-Fed Microbial Fuel Cell

The abundance of cellulosic wastes make them attractive source of energy for producing electricity in microbial fuel cells (MFCs). However, electricity production from cellulose requires obligate anaerobes that can degrade cellulose and transfer electrons to the electrode (exoelectrogens), and thus most previous MFC studies have been conducted using two-chamber systems to avoid oxygen contamination of the anode. Single-chamber, air-cathode MFCs typically produce higher power densities than aqueous catholyte MFCs and avoid energy input for the cathodic reaction. To better understand the bacterial communities that evolve in single-chamber air-cathode MFCs fed cellulose, we examined the changes in the bacterial consortium in an MFC fed cellulose over time. The most predominant bacteria shown to be capable electron generation was Firmicutes, with the fermenters decomposing cellulose Bacteroidetes. The main genera developed after extended operation of the cellulose-fed MFC were cellulolytic strains, fermenters and electrogens that included: Parabacteroides, Proteiniphilum, Catonella and Clostridium. These results demonstrate that different communities evolve in air-cathode MFCs fed cellulose than the previous two-chamber reactors.

Preliminary Characterization of a Cellulase Producing Bacterial Strain Isolated from a Romanian Hypersaline Lake

Cellulases are a group of enzymes that are used in many biotechnological processes. Since most of the enzymes synthesised by mesophilic microorganisms are unstable in industrial environments, it is necessary to direct research towards extremophile cellulolytic microorganisms because the enzymes synthesised by them are stable and active even in harsh physicochemical conditions. In the present investigation, our aim was to isolate and identify some microbial cellulolytic strains from a hypersaline lake located in Romania and to determine their optimal growth conditions. Of a total of 25 microbial strains isolated, only one extreme halotolerant bacterial strain was able to produce an endoglucanase. Based on molecular identification, we identified this cellulolytic strain as a species of Bacillus genus, most closely related to Bacillus zhangzhouensis. Optimal growth conditions were found to be at 15°C, pH 7.5 and 2 M NaCl. Endoglucanase activity of this bacterial strain is influenced by both salinity and temperature. The most significant endoglucanase activity was detected in the presence of 3 M NaCl, after 72 h of incubation at 15°C. In this situation, the amount of glucose released from a volume of 0.5 mL of 2% (w/v) carboxymethyl cellulose substrate is equivalent to 2.05 mg. In conclusion, this study represents the first preliminary characterization of a B. zhangzhouensis strain that has the ability to degrade cellulose and that demonstrates tolerance to high salt concentrations.

A bifunctional cellulase-xylanase of a new Chryseobacterium strain isolated from the dung of a straw-fed cattle.

SummaryA new cellulolytic strain of Chryseobacterium genus was screened from the dung of a cattle fed with cereal straw. A putative cellulase gene (cbGH5) belonging to glycoside hydrolase family 5 subfamily 46 (GH5_46) was identified and cloned by degenerate PCR plus genome walking. The CbGH5 protein was overexpressed in Pichia pastoris, purified and characterized. It is the first bifunctional cellulase–xylanase reported in GH5_46 as well as in Chryseobacterium genus. The enzyme showed an endoglucanase activity on carboxymethylcellulose of 3237 μmol min−1 mg−1 at pH 9, 90 °C and a xylanase activity on birchwood xylan of 1793 μmol min−1 mg−1 at pH 8, 90 °C. The activity level and thermophilicity are in the front rank of all the known cellulases and xylanases. Core hydrophobicity had a positive effect on the thermophilicity of this enzyme. When similar quantity of enzymatic activity units was applied on the straws of wheat, rice, corn and oilseed rape, CbGH5 could obtain 3.5–5.0× glucose and 1.2–1.8× xylose than a mixed commercial cellulase plus xylanase of Novozymes. When applied on spent mushroom substrates made from the four straws, CbGH5 could obtain 9.2–15.7× glucose and 3.5–4.3× xylose than the mixed Novozymes cellulase+xylanase. The results suggest that CbGH5 could be a promising candidate for industrial lignocellulosic biomass conversion.

A cold-active acidophilic endoglucanase of Paenibacillus sp. Y2 isolated from soil in an alpine region

A cellulolytic strain Y2 was isolated from soil obtained in the Canadian Alpine region. The isolate was identified as Paenibacillus sp. Y2 by 16S rRNA sequencing. When grown in LB medium supplemented with carboxymethyl-cellulose (CMC), CMCase production increased to 122.0% of that observed in LB wit...

Bacillus coagulans MA-13: a promising thermophilic and cellulolytic strain for the production of lactic acid from lignocellulosic hydrolysate

BackgroundThe transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed.ResultsA thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans, named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C.ConclusionsThe above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto employed for the depolymerisation of lignocellulosic biomasses to fermentable sugars. Moreover, the robustness of B. coagulans MA-13 is a desirable trait, given the presence of microbial growth inhibitors in the pre-treated biomass hydrolysate.

Study of Biochemical and Microbiological Properties During Co-composting of Spent Mushroom Substrates and Chicken Feather

To study the biochemical and microbiological properties during co-composting of chicken feather and spent mushroom substrates, chicken feather by incubation of multiple microorganisms were co-composted for 28 days with Pleurotus geesteranus-degraded Eucalyptus sawdust (PE), P. geesteranus-degraded weed tree sawdust (PW) and Ganoderma lucidum-degraded weed tree sawdust (GW), respectively. Characteristics of physico-chemical, enzymatic and microbiological parameters during composting were investigated in terms of temperature, pH, moisture, activities of CMCase, and succession of bacteria and fungus. Results showed that the peak temperature in PEC was 59 °C on 5 days. No ascaris egg was detected in the final composts of PEC, PWC and GWC. The pH of compost in PEC and GWC were about 8.5, which was higher than pH of compost in PWC 7.4. The activities of CMCase in PEC were significantly higher than PWC and GWC during composting. The OM and C/N on 28 days decreased compared to the raw materials. The PCR-DGGE profiles showed significant differences in structure of bacteria and fungus after composting. Four prominent species of bacteria were replaced by uncultured bacterium and the prominent species of fungus were thermophiles and cellulolytic strains on 28 days. Correlation properties were similarly shared by the physico-chemical parameter and bacteria as well as fungus.