Progress in the production of lignocellulolytic enzyme systems using Penicillium species / 生物工程学报

The efficient production of lignocellulolytic enzyme systems is an important support for large-scale biorefinery of plant biomass. On-site production of lignocellulolytic enzymes could increase the economic benefits of the process by lowering the cost of enzyme usage. Penicillium species are commonly found lignocellulose-degrading fungi in nature, and have been used for industrial production of cellulase preparations due to their abilities to secrete complete and well-balanced lignocellulolytic enzyme systems. Here, we introduce the reported Penicillium species for cellulase production, summarize the characteristics of their enzymes, and describe the strategies of strain engineering for improving the production and performance of lignocellulolytic enzymes. We also review the progress in fermentation process optimization regarding the on-site production of lignocellulolytic enzymes using Penicillium species, and suggest prospect of future work from the perspective of building a "sugar platform" for the biorefinery of lignocellulosic biomass.

Cloning and expression of an endoglucanase gene from the thermotolerant fungus Aspergillus fumigatus DBiNU-1 in Kluyveromyces lactis

Abstract An intronless endoglucanase from thermotolerant Aspergillus fumigatus DBINU-1 was cloned, characterized and expressed in the yeast Kluyveromyces lactis. The full-length open reading frame of the endoglucanase gene from A. fumigatus DBiNU-1, designated Cel7, was 1383 nucleotides in length and encoded a protein of 460 amino acid residues. The predicted molecular weight and the isoelectric point of the A. fumigatus Cel7 gene product were 48.19 kDa and 5.03, respectively. A catalytic domain in the N-terminal region and a fungal type cellulose-binding domain/module in the C-terminal region were detected in the predicted polypeptide sequences. Furthermore, a signal peptide with 20 amino acid residues at the N-terminus was also detected in the deduced amino acid sequences of the endoglucanase from A. fumigatus DBiNU-1. The endoglucanase from A. fumigatus DBiNU-1 was successfully expressed in K. lactis, and the purified recombinant enzyme exhibited its maximum activity at pH 5.0 and 60 °C. The enzyme was very stable in a pH range from 4.0 to 8.0 and a temperature range from 30 to 60 °C. These features make it suitable for application in the paper, biofuel, and other chemical production industries that use cellulosic materials.

Inducible cellulase production from an organic solvent tolerant Bacillus sp. SV1 and evolutionary divergence of endoglucanase in different species of the genus Bacillus

Abstract Bacteria are important sources of cellulases with various industrial and biotechnological applications. In view of this, a non-hemolytic bacterial strain, tolerant to various environmental pollutants (heavy metals and organic solvents), showing high cellulolytic index (7.89) was isolated from cattle shed soil and identified as Bacillus sp. SV1 (99.27% pairwise similarity with Bacillus korlensis). Extracellular cellulases showed the presence of endoglucanase, total cellulase and β-glucosidase activities. Cellulase production was induced in presence of cellulose (3.3 times CMCase, 2.9 times FPase and 2.1 times β-glucosidase), and enhanced (115.1% CMCase) by low-cost corn steep solids. An in silico investigation of endoglucanase (EC 3.2.1.4) protein sequences of three Bacillus spp. as query, revealed their similarities with members of nine bacterial phyla and to Eukaryota (represented by Arthropoda and Nematoda), and also highlighted of a convergent and divergent evolution from other enzymes of different substrate [(1,3)-linked beta-d-glucans, xylan and chitosan] specificities. Characteristic conserved signature indels were observed among members of Actinobacteria (7 aa insert) and Firmicutes (9 aa insert) that served as a potential tool in support of their relatedness in phylogenetic trees.

Production of thermostable ß-glucosidase and CMCase by Penicillium sp: LMI01 isolated from the Amazon region

Background: Cellulolytic enzymes of microbial origin have great industrial importance because of their wide application in various industrial sectors. Fungi are considered the most efficient producers of these enzymes. Bioprospecting survey to identify fungal sources of biomass-hydrolyzing enzymes from a high-diversity environment is an important approach to discover interesting strains for bioprocess uses. In this study, we evaluated the production of endoglucanase (CMCase) and ß-glucosidase, enzymes from the lignocellulolytic complex, produced by a native fungus. Penicillium sp. LMI01 was isolated from decaying plant material in the Amazon region, and its performance was compared with that of the standard isolate Trichoderma reesei QM9414 under submerged fermentation conditions. Results: The effectiveness of LMI01 was similar to that of QM9414 in volumetric enzyme activity (U/mL); however, the specific enzyme activity (U/mg) of the former was higher, corresponding to 24.170 U/mg of CMCase and 1.345 U/mg of ß-glucosidase. The enzymes produced by LMI01 had the following physicochemical properties: CMCase activity was optimal at pH 4.2 and the ß-glucosidase activity was optimal at pH 6.0. Both CMCase and ß-glucosidase had an optimum temperature at 60°C and were thermostable between 50 and 60°C. The electrophoretic profile of the proteins secreted by LMI01 indicated that this isolate produced at least two enzymes with CMCase activity, with approximate molecular masses of 50 and 35 kDa, and ß-glucosidases with molecular masses between 70 and 100 kDa. Conclusions: The effectiveness and characteristics of these enzymes indicate that LMI01 can be an alternative for the hydrolysis of lignocellulosic materials and should be tested in commercial formulations.

Isolation and characterization of a novel endo-beta-1, 4-glucanase from a metagenomic library of the black-goat rumen

ABSTRACT The various types of lignocellulosic biomass found in plants comprise the most abundant renewable bioresources on Earth. In this study, the ruminal microbial ecosystem of black goats was explored because of their strong ability to digest lignocellulosic forage. A metagenomic fosmid library containing 115,200 clones was prepared from the black-goat rumen and screened for a novel cellulolytic enzyme. The KG35 gene, containing a novel glycosyl hydrolase family 5 cellulase domain, was isolated and functionally characterized. The novel glycosyl hydrolase family 5 cellulase gene is composed of a 963-bp open reading frame encoding a protein of 320 amino acid residues (35.1 kDa). The deduced amino acid sequence showed the highest sequence identity (58%) for sequences from the glycosyl hydrolase family 5 cellulases. The novel glycosyl hydrolase family 5 cellulase gene was overexpressed in Escherichia coli. Substrate specificity analysis revealed that this recombinant glycosyl hydrolase family 5 cellulase functions as an endo-β-1,4-glucanase. The recombinant KG35 endo-β-1,4-glucanase showed optimal activity within the range of 30-50 °C at a pH of 6-7. The thermostability was retained and the pH was stable in the range of 30-50 °C at a pH of 5-7.

Escherichia coli expressing endoglucanase gene from Thai higher termite bacteria for enzymatic and microbial hydrolysis of cellulosic materials

Background: Endoglucanase plays a major role in initiating cellulose hydrolysis. Various wild-type strains were searched to produce this enzyme, but mostly low extracellular enzyme activities were obtained. To improve extracellular enzyme production for potential industrial applications, the endoglucanase gene of Bacillus subtilis M015, isolated from Thai higher termite, was expressed in a periplasmic-leaky Escherichia coli. Then, the crude recombinant endoglucanase (EglS) along with a commercial cellulase (Cel) was used for hydrolyzing celluloses and microbial hydrolysis using whole bacterial cells. Results: E. coli Glu5 expressing endoglucanase at high levels was successfully constructed. It produced EglS (55 kDa) with extracellular activity of 18.56 U/mg total protein at optimal hydrolytic conditions (pH 4.8 and 50°C). EglS was highly stable (over 80% activity retained) at 40­50°C after 100 h. The addition of EglS significantly improved the initial sugar production rates of Cel on the hydrolysis of carboxymethyl cellulose (CMC), microcrystalline cellulose, and corncob about 5.2-, 1.7-, and 4.0-folds, respectively, compared to those with Cel alone. E. coli Glu5 could secrete EglS with high activity in the presence of glucose (1% w/v) and Tween 80 (5% w/v) with low glucose consumption. Microbial hydrolysis of CMC using E. coli Glu5 yielded 26 mg reducing sugar/g CMC at pH 7.0 and 37°C after 48 h. Conclusions: The recombinant endoglucanase activity improved by 17 times compared with that of the native strain and could greatly enhance the enzymatic hydrolysis of all studied celluloses when combined with a commercial cellulase.

Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions

Abstract Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40 °C). Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively) were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days). After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic). However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity) and carbon release.

Cloning, expression and characterization of the endoglucanase gene from Bacillus subtilis UMC7 isolated from the gut of the indigenous termite Macrotermes malaccensis in Escherichia coli

Background Bacillus subtilis UMC7 isolated from the gut of termite Macrotermes malaccensis has the ability to secrete a significant amount of extracellular endoglucanase, with an enzyme activity of 0.12 ± 0.01 μmol/min/mL. However, for economically viable industrial applications, the enzyme needs to be expressed in a heterologous host to overcome the low enzyme production from the wild-type strain. Results The endoglucanase gene from B. subtilis UMC7 was successfully cloned and expressed. A higher enzyme activity was observed in the intracellular fraction of the recombinant clone (0.51 ± 0.02 μmol/min/mL) compared with the cell-bound fraction (0.37 ± 0.02 μmol/min/mL) and the extracellular fraction (0.33 ± 0.01 μmol/min/mL). The recombinant endoglucanase was approximately 56 kDa, with optimal enzyme activity at 60°C and pH 6.0. The activity of the enzyme was enhanced by the addition of Ca2 +. However, the enzyme was inhibited by other metal ions in the following order: Fe3 + > Ni2 + > Cu2 + > Mn2 + = Zn2 + > Mg2 + > Cd2 + > Cr2 +. The enzyme was able to hydrolyze both low- and high-viscosity carboxymethyl-cellulose (CMC), avicel, cotton linter, filter paper and avicel but not starch, xylan, chitin, pectin and p-nitrophenyl α-d-glucopyranoside. Conclusions The recombinant endoglucanase showed a threefold increase in extracellular enzyme activity compared with the wild-type strain. This result revealed the potential of endoglucanase expression in E. coli, which can be induced for the overexpression of the enzyme. The enzyme has a broad range of activity with high specificity toward cellulose.

Potential of giant reed (Arundo donax L. ) for second generation ethanol production

Background The production of second generation ethanol from lignocellulosic biomasses that have not had their potential fully explored as feedstock is of great importance. Arundo donax is one these biomasses. It is a promising grassy plant to be used as a renewable resource for the production of fuels and chemicals, because of its fast growth rate, ability to grow in different soil types and climatic conditions. The present study evaluated its use as feedstock for the production of second generation ethanol. Results Initially its chemical characterization was carried out, and a protocol for fractioning the biomass through diluted acid pretreatment followed by alkaline pretreatment was developed, providing a solid fraction which was undergone to enzymatic hydrolysis reaching 42 g/L of glucose, obtained in 30 h of enzymatic hydrolysis. This partially delignified material was subjected to a simultaneous saccharification and fermentation (SSF) process, resulting in an ethanol concentration of 39 g/L at 70 h. Conclusions The fermentability of the pretreated biomass was performed successfully through the conception of simultaneous saccharification and fermentation resulting in approximately 75 L of ethanol per ton of cellulose.

Bioprocessing of some agro-industrial residues for endoglucanase production by the new subsp.; Streptomyces albogriseolus subsp. cellulolyticus strain NEAE-J

The use of low cost agro-industrial residues for the production of industrial enzymes is one of the ways to reduce significantly production costs. Cellulase producing actinomycetes were isolated from soil and decayed agricultural wastes. Among them, a potential culture, strain NEAE-J, was selected and identified on the basis of morphological, cultural, physiological and chemotaxonomic properties, together with 16S rDNA sequence. It is proposed that strain NEAE-J should be included in the species Streptomyces albogriseolus as a representative of a novel sub-species, Streptomyces albogriseolus subsp. cellulolyticus strain NEAE-J and sequencing product was deposited in the GenBank database under accession number JN229412. This organism was tested for its ability to produce endoglucanase and release reducing sugars from agro-industrial residues as substrates. Sugarcane bagasse was the most suitable substrate for endoglucanase production. Effects of process variables, namely incubation time, temperature, initial pH and nitrogen source on production of endoglucanase by submerged fermentation using Streptomyces albogriseolus subsp. cellulolyticus have been studied. Accordingly optimum conditions have been determined. Incubation temperature of 30 ºC after 6 days, pH of 6.5, 1% sugarcane bagasse as carbon source and peptone as nitrogen source were found to be the optimum for endoglucanase production. Optimization of the process parameters resulted in about 2.6 fold increase in the endoglucanase activity. Therefore, Streptomyces albogriseolus subsp. cellulolyticus coud be potential microorganism for the intended application.

Filamentous fungi and media for cellulase production in solid state cultures

Cellulase production was evaluated in two reference strains (T. reesei Rut-C30 and T. reesei QM9414), two strains isolated from a sugarcane cultivation area (Trichoderma sp. IPT778 and T. harzianum rifai IPT821) and one strain isolated in a program for biodiversity preservation in São Paulo state (Myceliophthora thermophila M77). Solid state cultures were performed using sugarcane bagasse (C), wheat bran (W) and/or soybean bran (S). The highest FPA was 10.6 U/gdm for M77 in SC (10:90) at 80% moisture, which was 4.4 times higher than production in pure W. C was a strong inducer of cellulase production, given that the production level of 6.1 U/gdm in WC (40:60) was 2.5 times higher than in pure W for strain M77; T. reesei Rut-C30 did not respond as strongly with about 1.6-fold surplus production. S advantageously replaced W, as the surplus production on SC (20:80) was 2.3 times relative to WC (20:80) for M77.

Low cost single-step purification of endoglucanase from Aspergillus fumigatus ABK-9.

Low cost agro-waste was used as adsorption support for single-step purification of endoglucanase from the culture filtrate of A. fumigatus ABK-9. Among various agro-waste substrates, 1% NaOH pretreated rice bran was proved to be the best for adsorbing about 74.8 and 71.1% of endoglucanase at 4 °C and 10 °C respectively. Langmuir type adsorption isotherm at 4 °C showed maximum adsorption of enzyme at pH 5.0, which was in the range of optimum pH of the enzyme. The rice bran column bound enzyme was maximally eluted by a mixture of acetate buffer (0.05 M, pH 5.5) and ethanol (40%, v/v) at a ratio of 3:2 and a flow rate of 1 mL/min. A 5.52-fold purification of the enzyme was achieved from culture supernatant. The specific activity and recovery yield after purification were 294.0 U/mg and 40.15%, respectively, which were comparable with other contemporary protocols. The homogeneity of the enzyme was tested through sodium dodecyl sulphate polyacrylamide gel electrophoresis and a single band of 56.3 kDa was observed. Zymogram analysis finally confirmed the occurrence of endoglucanase in the single band.

Sugarcane bagasse as feedstock for cellulase production by Trichoderma harzianum in optimized culture medium

This work aimed at the production of cellulases from pretreated sugarcane bagasse by the filamentous fungus Trichoderma harzianum IOC 3844 and their application in the hydrolysis of this same substrate, for a future use in second-generation ethanol production. The production of cellulases was optimized, which resulted in high enzymatic activities after 42 hrs of process in an instrumented bioreactor (CMCase 27,017 U x L-1; FPase 1,225 U x L-1; and β-glucosidase 609 U x L-1). The enzymatic extract was concentrated by using a hollow fiber membrane filtration system. The concentrated extract was applied in the hydrolysis of pretreated sugarcane bagasse, after 28 hrs of enzymatic reaction, displaying a similar catalytic performance of that attained with a commercial enzymatic preparation (hydrolysis efficiency of roughly 50%). Finally, the enzymatic extract was partially characterized in terms of the molecular weights of the main activities of the enzymatic pool. Electrophoretic analysis identified eleven protein bands; six of them were related to CMCase activity and revealing molecular weights that varied from 48 to 78 kDa, and two bands were associated with β-glucosidase activity and having molecular weights of 75 and 85 kDa.

Production of cold-adapted cellulase by Verticillium sp. isolated from Antarctic soils

Background: Cellulose can be converted to ethanol by simultaneous saccharification and fermentation (SSF). The difference between the optimal temperature of cellulase and microbial fermentation, however, has been identified as the critical problem with SSF. In this study, one fungal strain (AnsX1) with high cellulase activity at low temperature was isolated from Antarctic soils and identified as Verticillium sp. by morphological and molecular analyses. Results: The biochemical properties of crude AnsX1 cellulase samples were studied by filter paper cellulase assay. The maximum cellulase activity was achieved at low temperature in an acidic environment with addition of metal ions. Furthermore, AnsX1 cellulase demonstrated 54-63% enzymatic activity at ethanol concentrations of 5-10%. AnsX1 cellulase production was influenced by inoculum size, carbon and nitrogen sources, and elicitors. The optimal culture conditions for AnsX1 cellulase production were 5% inoculum, wheat bran as carbon source, (NH4)2SO4 as nitrogen source, and sorbitol added in the medium. Conclusions: Our present work has potential to enable the development of an economic and efficient cold-adapted cellulase system for bioconversion of lignocellulosic biomass into biofuels in future.

Purification and biochemical characterization of endoglucanase from Penicillium pinophilum MS 20.

Cellulases find increasing prominence in sustainable production of fuel and feedstock from lignocellulosic biomass. The purification and biochemical characterization of individual components of cellulase complex is important to understand the mechanism of their action for the solubilization of crystalline cellulose. In this study, an extra-cellular endoglucanase isolated from culture filtrate of Penicillium pinophilum MS 20 was purified to homogeneity by ammonium sulphate precipitation, ion-exchange chromatography and gel filtration. The purified endoglucanase (specific activity 69 U/mg) was a monomeric protein with molecular mass of 42 kDa, as determined by SDS-PAGE. The endoglucanase was active over a broad range of pH (4-7) with maximum activity at pH 5 and showed optimum temperature of 50°C. It retained 100% activity at 50°C for 6 h and half- lives of 4 h and 3 h at 60°C and 70°C, respectively. The kinetic constants for the endoglucanase determined with carboxymethyl cellulose as substrate were Vmax of 72.5 U/mg and apparent Km of 4.8 mg/ml. The enzyme also showed moderate activity towards H3PO4 swollen cellulose and p-nitrophenyl β-D-glucoside, but no activity towards filter paper, Avicel and oat spelt xylan. The activity was positively modulated by 47, 32 and 25% in the presence of Co2+, Zn2+ and Mg2+, respectively to the reaction mixture. The wide pH stability (4-7) and temperature stability up to 50°C of endoglucanase makes the enzyme suitable for use in cellulose saccharification at moderate temperature and pH.

Grape stalks as substrate for white rot fungi, lignocellulolytic enzyme production and dye decolorization / Uso del escobajo como sustrato para el crecimiento de hongos de la pudrición blanca, la producción de enzimas ligninolíticas y la decoloración de tinturas

The aim of this work was to evaluate the potential of grape stalks, an agroindustrial waste, for growth and lignocellulolytic enzyme production via solid-state fermentation, using the following three white rot fungi: Trametes trogii, Stereum hirsutum and Coriolus antarcticus. The decolorization of several dyes by the above mentioned cultures was also investigated. Similar values of dry weight loss of the substrate were measured after 60 days (33-43 %). C. antarcticus produced the highest laccase and Mn-peroxldase activities (33.0 and 1.6 U/g dry solid). The maximum endoglucanase production was measured in S. hirsutum cultures (10.4 U/g), while the endoxylanase peak corresponded to T. trogii (14.6 U/g). The C. antarcticus/grape stalk system seems potentially competitive in bioremediation of textile processing effluents, attaining percentages of decolorization of 93, 86, 82, 82, 77, and 58 % for indigo carmine, malachite green, azure B, remazol brilliant blue R, crystal violet and xylidine, respectively, in 5 h.

El objetivo de este trabajo fue evaluar el potencial del escobajo, un residuo agroindustrial, como sustrato para el crecimiento y la producción de enzimas lignocelulósicas de tres hongos causantes de pudrición blanca en la madera: Trametes trogii, Stereum hirsutum y Coriolus antarcticus. Para ello se utilizaron técnicas de fermentación en estado sólido. También se ensayó la decoloración de colorantes industriales sobre estos cultivos. La pérdida de peso seco del sustrato fue similar después del día 60 (33-43 %). C. antarcticus produjo las mayores actividades de lacasa y Mn-peroxidasa (33,0 y 1,6 U/g peso seco). La mayor actividad endoglucanasa fue medida en cultivos de S. hirsutum (10,4 U/g), y la mayor actividad endoxilanasa en T. trogii (14,6 U/g). El sistema C. antarcticus/escobap mostró un importante potencial para su aplicación en la biorremediación de efluentes textiles, con porcentajes de decoloración de 93, 86, 82, 82, 77 y 58 % para índigo carmín, verde de malaquita, azure B, azul R brillante de remazol, cristal violeta y xilidina, respectivamente, en 5 h.

Bioconversion and saccharification of some lignocellulosic wastes by aspergillus oryzae ITCC-4857.01 for fermentable sugar production

The recent interest in bioconversion of agricultural and industrial wastes to chemical feedstock has led to extensive studies on cellulolytic enzymes produced by microorganisms. In the present study three lignocellulosic substrates viz. sugarcane bagasse, sawdust and water hyacinth were pre-treated with alkali and enzyme and their effect on bioconversion has been investigated. The ability of selected substrates for induction of cellulase enzyme by A. oryzae ITCC 4857.01 and for the potentiality of the induced enzyme to saccharify the substrates were also assessed. The maximum degree of conversion of substrate (0.415 percent) and improved specific substrate consumption (0.99 g substrate/g dry biomass) was exhibited in sugarcane bagasse after alkali treatment at 96 hrs. Both alkali-treatment and enzyme-treatment, water hyacinth was the best for cellulase induction and showed maximum endoglucanase activity of 11.42 U/ml. Reducing sugar yield ranged from 1.12 mg/ml for enzyme treated sawdust at 48 hrs to 7.53 mg/ml for alkali treated sugarcane bagasse at 96 hrs. Alkali-treated sugarcane bagasse gave the highest saccharification rate of 9.03 percent after 96 hrs. The most resistant substrate was sawdust which produced 5.92 percent saccharification by alkaline treatment. The saccharification of lignocellulosic substrates by enzyme produced by A. oryzae ITCC 4857.01 indicates the enzymes specificity towards the substrates. The use of such enzyme in lingo-cellulose hydrolysis will lead to efficient conversion of cellulose materials to other important products.

Isolation and characterization of a novel lignocellulose decomposing fungal strain.

A strain F1 with high cellulase activity obtained from the deadwood stack was characterized as Ceriporia lacerate by examination of the general taxonomical characteristics and phylogenetic sequence analysis of rDNA ITS gene. The endoglucanase (EG) and filter paper cellulase (FPase) activities of the strain showed remarkable stability in the pH range of 4.0-7.0, and maintained about their maximal value of 76% and 50% after incubation at 70˚C for 6 h respectively. The strain grew particularly well with CMC-Na (1.0%) and yeast extract (0.4%) at 28˚C (pH 6.0) in flasks stirred at 150 × g for 6 days. Based on the thermostability and pH stability of cellulase, the strain appears to have potential in industrial applications and bioresource utilization.

Agricultural waste from the tequila industry as substrate for the production of commercially important enzymes.

Approximately 1 million tons of Agave tequilana plants are processed annually by the Mexican Tequila industry generating vast amounts of agricultural waste. The aim of this study was to investigate the potential use of Agave tequilana waste as substrate for the production of commercially important enzymes. Two strains of Aspergillus niger (CH-A-2010 and CH-A-2016), isolated from agave fields, were found to grow and propagate in submerged cultures using Agave tequilana waste as substrate. Isolates showed simultaneous extracellular inulinase, xylanase, pectinase, and cellulase activities. Aspergillus CH-A-2010 showed the highest production of inulinase activity (1.48 U/ml), whereas Aspergillus niger CH-A-2016 produced the highest xylanase (1.52 U/ml) and endo-pectinase (2.7U/ml) activities. In both cases production of enzyme activities was significantly higher on Agave tequilana waste than that observed on lemon peel and specific polymeric carbohydrates. Enzymatic hydrolysis of raw A. tequilana stems and leaves, by enzymes secreted by the isolates yielded maximum concentrations of reducing sugars of 28.2 g/l, and 9.9 g/l respectively. In conclusion, Agave tequilana waste can be utilized as substrate for the production of important biotechnological enzymes.

Solid state cultivation of Curvularia lunata for transformation of rifamycin B to S.

Biotransformation of rifamycin B to rifamycin S using two strains of C. lunata namely NCIM 716 and NMU grown on various solid substrates viz., grass, paper, jowar/wheat straw, bran and bagasse was studied. Almost complete biotransformation efficiency of rifamycin B at 0. 06 mM concentration was observed within 24 hr. Among these two strains, C. lunata NMU showed 90% of biotransformation and higher rate of cellulose utilization on solid substrates vis-à-vis reference strain. Cellulase activity of both strains was also studied for exoglucanase, endoglucanase and beta-glucosidase. Column bioreactor studies with bagasse revealed further improvement in biotransformation efficiency of C. lunata NMU.