Extra Nitrogen Source Research Articles

Перспективы глубокой переработки бумажного шлама с применением ферментов, микроводорослей и дрожжей

This article presents the information on the valorization of waste generated during the production of tissue paper. The possibility of bioconversion of the polysaccharide part of paper sludge into simple sugars has been evaluated. The options for processing the paper sludge before enzymic hydrolysis to achieve the maximum yield of monosaccharides have been considered. Pretreatment with acids has been found to be a key step before the biocatalytic cleavage of waste polysaccharides. An additional yield of enzymic hydrolysis products after pretreatment with acids has been obtained by pre-extraction of the paper sludge with spirit or acetone. It has been established that the most intense enzymic hydrolysis of readily available fractions of the paper sludge takes place in the first 10–12 hours. Further, the process slows down, probably due to the action of the remaining components of the fillers, as well as an increase in the proportion of the difficult-to-hydrolyze polysaccharide part. In all cases, the proportion of absolutely dry non-hydrolyzed residue has been about 43±2 % of the dry matter of the paper sludge. The main products of enzymic hydrolysis have been glucose and xylose. The resulting sugars have been used for mixotrophic cultivation of the Tetradesmus obliquus and Chlorella vulgaris algae. Yeast strains have been selected for the conversion of monosaccharides from the paper sludge. In a series of experiments on non-sterile yeast cultivation, the Candida utilis PAL D and Debaryomyces hansenii SWING R cultures have turned out to be the most productive (within 2.10±0.14 g of air-dry yeast weight/dm3 per 24 hours). The degree of conversion of hydrolysate sugars has been 70±2 %. Most of the remaining sugars (about 80 %) have been represented by xylose. Complete utilization of the sugars has taken place on the 2nd day when having added an extra nitrogen source to the medium. On the other hand, the spent nutrient medium after yeast separation has been suitable for mixotrophic cultivation of microalgae. It has been revealed that the economic costs of pre-treatment of the paper sludge with nitric acid can be leveled by using the resulting salts as a nitrogen source for cultivating yeast. In doing so, the yield of yeast biomass increases by almost 2 times.

Optimization of the extracellular secretion of black goat rumen metagenome-derived KG42 xylanase by Bacillus subtilis

Xylanase (E.C. 3.2.1.8) is the enzyme that breaks down β-1,4 xylan by cleaving β-1,4 glycosidic linkages. Production of xylanases is important for various industrial applications. Here, we aimed to determine the optimal incubation conditions for expression and secretion of KG42 xylanase in Bacillus subtilis using response surface methodology based on Box-Behnken design in preparation for industrial applications. Among nine broth media tested in this study, Power Broth was chosen as a basal medium. In addition to the basal medium, the four other independent variables of extra carbon sources (glucose, lactose, mannose, fructose, and sucrose), extra nitrogen sources (beef extract, yeast extract, tryptone, urea, NaNO3, and (NH4)2SO4), isopropyl β-D-1-thiogalactopyranoside concentrations, and induction times were individually tested using one factor at a time in an optimization experiment. Next, a Box-Behnken design-based response surface methodology approach was used to identify and validate the optimized incubation conditions with the four variables in batch culture. The statistically optimized incubation conditions obtained from this study yielded a maximum of approximately 3- to 4-fold increases in the expression and secretion of KG42 xylanase by B. subtilis in comparison with unoptimized medium and incubation conditions.

Study on CO2 adsorption performance of biocarbon synthesized in situ from nitrogen-rich biomass pomelo peel

Recycling biomass to prepare CO2 adsorbent has been emphasized due to the benefits such as easy availability of materials, green and sustainable. Furthermore, functional groups containing nitrogen can promote the capacity of biochar to adsorb CO2. Usually, the production of N-doped porous carbon involves the chemical addition of amines or compounds containing nitrogen, which leads to pore blockage. For this reason, pomelo peel was used as a nitrogen-rich precursor of biomass to achieve nitrogen self-doping in this paper, and ZnCl2 was uniformly loaded as an activator using the impregnation method. After carbonization at 800 ℃ and template removal, an efficient porous carbon adsorbent was obtained without adding extra nitrogen sources. The N content of the biocarbon was retained from 2.60 to 5.98 at% employing pre-carbonation. We also systematically analyzed the modification of the CO2 adsorption effect by ultra-microporous structure and N atom doping. The former content showed almost no linear correlation with the adsorption data, but rather a synergistic effect with N content influenced the adsorption results under environmental conditions. The optimal adsorption of CO2 was 3.01 mmol g−1 (25 °C, 1 bar) and 4.83 mmol g−1 (0 °C, 1 bar). In addition, the adsorbent PPC-4 has excellent CO2/N2 adsorption selectivity of 38 and cyclic adsorption performance.

Coordination compound-derived Fe4N/Fe3N/Fe/CNT for efficient electrocatalytic oxygen evolution: a facile one-step synthesis in the absence of extra nitrogen source

By annealing an Fe(III)–coordination compound (Fe–CC), [FeCl3(Hbta)2] (Hbta = benzotriazole) in the presence of a carbon nanotube precursor (PCNT) template, an Fe4N/Fe3N/Fe/CNT heterostructure was successfully synthesized without an extra nitrogen source. The decomposition of the Hbta in Fe–CC under high-temperature annealing can produce carbon sheets and reduced graphene oxide (rGO), and the presence of CNTs can alleviate the stacking of the in situ-generated carbon materials. Meanwhile, iron nitride nanoparticles (NPs) can be anchored on the carbon sheets, and the anchoring effect efficiently prevents the agglomeration of NPs and increases the amount of active catalytic sites for the oxygen evolution reaction (OER). Fe4N/Fe3N/Fe/CNT shows an excellent OER activity with a Tafel slope of 63 mV dec−1 as well as overpotentials of 121 (η 10) and 275 mV (η 100) at 10 and 100 mA cm−2, respectively — far exceeding commercial RuO2 and other catalysts. Density functional theory calculations show that the excellent OER performance of Fe4N/Fe3N/Fe/CNT is associated with the Fe4N/Fe3N heterojunction, which can improve the electron conductivity and boost the electron transfer from N to Fe. The Fe4N/Fe3N/Fe/CNT catalyst exhibits long-term OER activity during 100 h of electrolysis at 20 mA cm−2. This is related to the dual coatings of the in situ-generated thin carbon shell and few-layered rGO on the surface of the iron nitride NPs, which can protect the fast leaching of iron nitride during the OER process. Furthermore, the effects of the annealing temperature, the PCNT template and the heating rate on the calcined products were investigated.

Strategy for boosting Co-Nx content for oxygen reduction reaction in aqueous metal-air batteries

Electrocatalyst is the pivotal component promoting the kinetics of oxygen reduction reaction in aqueous metal-air batteries. However, the content of increased bond as the active species is usually limited by the metal loading, tiny pore canal, insufficient nitrogen further restraining the electrocatalytic effectiveness of single-atom catalysts in oxygen reduction reaction (ORR). Herein, Co, N-dual doped carbon (Co/NNC) is prepared by a versatile strategy of the combination approach of SiO2 template with extra nitrogen source. Based on ZIF-67 prepared with the assistance of SiO2 template, the extra nitrogen source was introduced in the high-temperature pyrolysis procedure. The material characterizations of XRD, SEM, HRTEM, BET, Raman and XPS are conducted to synthetically analyze the functional role of extra nitrogen source. Moreover, the Co/NNC with increased Co-Nx active sites is employed into two aqueous metal-air batteries of Zn-air and Mg-air batteries, which exhibits excellent performances especially in the aspects of discharge specific capacity, discharge stability and power density.

Coordination Polymer-Derived Fe3N Nanoparticles for Efficient Electrocatalytic Oxygen Evolution.

Based on a coordination polymer, FeCl2(4,4'-bpy) (4,4'-bpy = 4,4'-bipyridine) and the carbon nanotube (CNT)/NaCl dual template, Fe3N nanoparticles (NPs) were synthesized via chemical thermolysis in the absence of an extra nitrogen source. The decomposition of 4,4'-bpy under high temperature produces thin carbon coating for Fe3N NPs. Also, the CNT template anchors the Fe3N NPs to avoid aggregation. The sample (denoted as Fe3N-C N) exhibits excellent electrocatalytic oxygen evolution reaction (OER) behavior even with a small molar ratio of Fe3N (Fe: 4.9 at. %), which can deliver a current density of 10 mA cm-2 at an overpotential of 218 mV with a Tafel slope of 84 mV dec-1 and long-term OER activity during 60 h electrolysis at 20 mA cm-2. Furthermore, the sample after 20 h electrolysis, denoted as Post-Fe3N-C N (20 h), displays enhanced OER activity with a smaller Tafel slope of 41 mV dec-1 and overpotentials of 195 and 327 mV at 10 and 100 mA cm-2, respectively, which is mainly due to the partial transformation of Fe3N into FeOOH. The OER mechanism is investigated by density functional theory calculations, and it is found that the surface partial oxidation of Fe3N leads to the effective OER electrolysis, which changes the electron density of the superficial atoms and induces the moderate adsorption for the intermediates.

Bioconversion of wastewater-derived duckweed to lactic acid through fed-batch fermentation at high-biomass loading

After being collected from the wastewater treatment system, duckweed biomass which is rich in starch and protein has the potential to be converted to valuable chemicals. This study aimed to establish a fermentation process for bioconversion of duckweed biomass derived from wastewater treatment to lactic acid (LA) by Lactobacillus casei. The Lactobacillus casei CICC 23184 showed the best LA production ability in duckweed-based medium among five strains. Simultaneous saccharification and fermentation (SSF) and separated hydrolysis and fermentation (SHF) were conducted, and the SSF had better performance even with lower enzyme dosage. No extra nitrogen source needed supplying into duckweed-based media. In batch fermentation, biomass loading of 220 g kg−1 was optimal with LA concentration of 72.51 ± 2.81 g kg−1 and yield of 0.35 ± 0.01 g g−1dry biomass. The highest LA concentration (100.36 ± 3.31 g kg−1), yield (0.38 ± 0.01 g g−1dry biomass), and productivity (2.09 ± 0.07 g kg−1 h−1) were obtained through fed-batch SSF at a final biomass loading of 260 g kg−1. This study demonstrated that it is feasible to utilize duckweed biomass as feedstock to produce LA through fermentation, and a fed-batch SSF at high-biomass loading was successfully established. This study provides a novel strategy for sustainable recycling of duckweed biomass derived from wastewater treatment.

Controllable excitation-dependent fluorescence triggered by the increasing graphitic nitrogen in carbon dots and its application in multi-analyte detection

Carbon dots (CDs) with controllable excitation-dependent fluorescence (EDFL) were elaborately prepared for the application of multiplex metal ion discrimination. A serial of CD samples were synthesized through a simple solvothermal reaction in which extra nitrogen sources with enhancing chemical reducibility were added into a specific nitrogen-contained precursor. Both experimental characterizations and theoretical calculations based on density functional theory have proved that the functional group of graphitic nitrogen (GN) is the key factor to achieve EDFL, and the content of GN was determined by the reducibility strength of extra nitrogen sources in the synthesis. In that case, sensing channels with different response behaviours to multiplex analytes can be formed due to the controllable EDFL of CDs. As a result, seventeen types of metal ions can be detected and recognized through the as-prepared CD probes. This work provides a novel angle to understand and engineer the EDFL property of CDs, as well as a facile strategy to appropriately construct high effective sensing channels for multi-analyte detection.

Nutrient recovery from tofu whey wastewater for the economical production of docosahexaenoic acid by Schizochytrium sp. S31

Docosahexaenoic acid plays a vital role in human health as it is essential for the proper function of the nervous system and for visual functions. To decrease the cost of docosahexaenoic acid production by Schizochytrium, the cost of the medium should be further decreased. In this study, the use of tofu whey wastewater to culture Schizochytrium sp. for docosahexaenoic acid production was tested, with the goal of reducing the medium cost. The results indicated that tofu whey wastewater presented a better culture performance with respect to biomass, lipid, and docosahexaenoic acid production compared with three traditional media. Through simple pH adjustment, the biomass and docosahexaenoic acid productivity reached 1.89 and 0.24 g/L/day, respectively, which were much higher than those obtained using traditional medium. The removal efficiency of chemical oxygen demand, total nitrogen, and total phosphorus reached 64.7, 66.0, and 59.3%, respectively. Due to the rich nutrients in tofu whey wastewater, the use of extra nitrogen source was avoided and the total medium cost for docosahexaenoic acid production in cultures using tofu whey wastewater was <1/3 of that of traditional media. This result indicated that tofu whey wastewater is an effective and economic basal medium for docosahexaenoic acid production by Schizochytrium sp.

Fabrication of highly N-Doped graphene-like carbon templated from g-C3N4 nanosheets as promising Li-ions battery anode

Nitrogen atoms doping was widely recognized as the promising technique to improve the electrochemical performances of various carbonaceous materials application for energy storage devices. Herein, we reported a facial fabrication of highly N-doped graphene-like carbon (NGC) through the carbonization of a mixture containing polypyrrole and g-C3N4 nanosheets, which was employed as sacrificial template and extra nitrogen source simultaneously. The resultant NGC material integrate a range of excellent features including high nitrogen contents (17.54 at%), large specific surface areas (635.73 m2 g−1) and abundant mesopores with high pore volume (1.9483 cm3 g−1). As anode material in Li-ions batteries, the NGC material exhibits an promising initial discharge capacity of 2749 mAh g−1 at a current density of 50 mA g−1 and encouraging cycling stability (1143 mAh g−1 after 200 cycles) as well as excellent rate performance (440 mAh g−1 at 2 A g−1). This feasible fabrication presents a new guidance to exploit high performance N-doped carbon materials for the applications in energy storage devices.

Antioxidant properties and antibacterial activity of fermented Monascus purpureus extracts

Monascus rice ferment extracts has anti-oxidant and antibiotic efficiency. Oxidative stress contributes to skin aging and can adversely affect skin health, which means antioxidants active in skin cells may support skin health. Antioxidant can contribute to defending old. Suppress the production that the epidermis bacterium can reduce the whelk and comedo. Our objective to evaluate the antioxidant properties, antibacterial activity and protective effects on UV-induced damage in HaCaT keratinocytes of extra different carbon and nitrogen sources at water (MRW) and methanolic (MRM) extracts from Monascus purpureus BCRC 31615 fermented rice. Effectiveness in reducing powers and DPPH radical scavenging ability was Monascus rice add MSG water extract has prominent ability. The ferment rice added nitrogen source to increase total phenols and kojic acid content. Antibacterial activities showed good in inhibition Staphylococcus aureus BCRC 10780. Protective effects on UV-induced damage in HaCaT keratinocytes which M. purpureus ferment rice added with extra nitrogen source was especially potent in inhibited UV-induced keratinocyte death.

Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa, PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH4Cl, NaNO3, or NaNO2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH4Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO3 and NaNO2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species.IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that bioaugmentation strains of bacteria might also be susceptible to invasion by social cheaters and that the nitrogen sources available in the wastewater might influence the ability of cheaters to overtake the bioaugmentation strains. Our results imply that control over the nitrogen sources in a wastewater stream or selective addition of certain nitrogen sources could help stabilize bioaugmentation strains of bacteria.

Performance and Influencing Factors of Dissimilatory Nitrate Reduction to Ammonium Process by the Strain Desulfovibrio sp. CMX

The process of dissimilatory nitrate reduction to ammonium (DNRA) plays an important role in the presence and conversion of ammonium ions in nature. However, the influencing factors and mechanisms of DNRA process in sulfate-reducing bacteria (SRB) have not yet been identified. The ability, influencing factors and mechanisms of DNRA was investigated in Desulfovibrio sp. CMX isolated previously in our laboratory. The results showed that the production rate of ammonium reached 85.8% and 97.3% respectively with NO3- and NO2- (10 mmol·L-1) as the sole electron donor and nitrogen source. Meanwhile, there was no by-products such as N2 and N2O. Then the effects of different extra nitrogen sources and initial concentrations of sulfate and sulfide on DNRA process were also investigated. As a result, extra nitrogen, yeast extract, could promote DNRA process by improving both growth and metabolism of the strain. In another study, sulfate promoted the nitrate reduction stage while inhibited the nitrite reduction. Overall, the DNRA process by Desulfovibrio sp. CMX was inhibited by sulfate. In addition, both the growth and two stages of the DNRA process were inhibited in the presence of sulfide. Dose effect of sulfide was observed. Inhibition was enhanced with the increase of sulfide concentration. It's noticeable that the inhibition on nitrate reduction was stronger than the inhibition on nitrite reduction with 6 mmol·L-1 of sulfide, leading to the lower reduction rate of nitrate than that of nitrite. In this condition, no accumulation of nitrite was observed in the system.

Elicitation of Jerusalem artichoke (Helianthus tuberosus L.) cell suspension culture for enhancement of inulin production and altered degree of polymerisation.

Plant cell suspension cultures have emerged as a potential source of secondary metabolites for food additives and pharmaceuticals. In this study inulin accumulation and its degree of polymerisation (DP) in the treated cells in the same medium were investigated after treatment with six types of elicitors. An in vitro cell suspension culture of Jerusalem artichoke (Helianthus tuberosus L.) was optimised by adding an extra nitrogen source. According to the growth kinetics, a maximum biomass of 5.48 g L-1 was obtained from the optimal cell suspension medium consisted of Murashige and Skoog basic medium (MS) + 1.0 mg L-1 α-naphthalene acetic acid (NAA) + 1.0 mg L-1 6-benzylaminopurine (6-BA) + 0.5 mg L-1 proline + 1.0 mg L-1 glutamine. Methyl jasmonate (MeJA, 250 µmol L-1 ) treatment for 15 days led to the highest levels of inulin (2955.27 ± 9.81 mg L-1 compared to control of 1217.46 ± 0.26 mg L-1 ). The elicited effect of five elicitors to the suspension cells of Jerusalem artichoke is as follows: AgNO3 (Ag, 10 µmol L-1 ), salicylic acid (SA, 75 µmol L-1 ), chitosan (KJT, 40 mg L-1 ), Trichoderma viride (Tv, 90 mg L-1 ), yeast extract (YE, 0.25 mg L-1 ), and the corresponding content of inulin is increased by 2.05-, 1.93-, 1.76-, 1.44- and 1.18-fold compared to control, respectively. The obvious effect on the percentage of lower DP in inulin was observed in cells treated with 40 mg L-1 KJT, 0.25 mg L-1 YE and 10 µmol L-1 Ag. Among the six types of elicitors, the descending order of inulin content is MeJA > Ag > SA > KJT > Tv > YE. For the purpose inulin with lower DP and its application to prebiotic food, three elicitors, including KJT, YE and Ag, can be used for the elicitation. © 2016 Society of Chemical Industry.

Iron incorporation on graphene nanoflakes for the synthesis of a non-noble metal fuel cell catalyst

In the present work, graphene nanoflakes (GNFs) were grown at both low and high levels of nitrogen functionalization and subsequently put through a wet-chemical method to add iron functionalities to the surface and create active catalyst centers. No mechanical treatments are used in order to minimize the formation of defects on the GNFs and evaluate if iron-nitrogen-GNF edges or surface sites can generate catalytic activity rather than the macropore structures holding these functionalities on porous carbon black. The catalysts produced under various synthesis routes were characterized and screened for their performance as an oxygen reduction reaction (ORR) catalyst. Characterization included an electrochemical study, an examination of the carbon and nitrogen content and bonding structure, in addition to Raman analysis and the calculation of the BET surface areas. It was found that samples that were both treated with iron acetate and put through pyrolysis produced the most active samples. These samples were composed of graphitic carbon and contained a large amount of pyridinic nitrogen. Additionally, when working with GNFs generated with high levels of nitrogen, no extra nitrogen source was needed during the iron incorporation step. This study further develops the GNF-based catalyst already seen to be a suitable ORR catalyst for the polymer electrolyte membrane fuel cell.

Tribological Characterization of Boron Nitride Films against Pure-titanium for Microforming die Application

Boron nitride films were deposited onto Si substrates by hot filament chemical vapor deposition. The Tris(dimetylamino)borane (B[N(CH3)2]3) was used as source precursor, and the ammonia gas was used as the extra nitrogen source to increase the N concentration in the films. The bias was applied on the substrate stage to obtain the cubic phase of boron nitride. Structures and compositions of the films were investigated by energy dispersive X-ray (EDX) analysis and Raman spectroscopy. BN films contain hexagonal structures were deposited. To verify whether the films can be applied to the microforming die for forming pure titanium, the ball-on-disk test was carried out with pure titanium as the counterpart. The interfacial behavior between the films and pure titanium was also investigated by observe the wear track after the ball-on-disk test. The result shows that there was no titanium adhesion on the wear track when BN films were remained.

Towards Industrially Feasible Treatment of Potato Starch Processing Waste by Mixed Cultures

The present study aimed at reducing the pollution of the waste generated by the potato starch industry to the environment and transform the potato pulp and wastewater into single-cell protein (SCP) to be used as animal feed. The chemical oxygen demand of the wastewater was reduced from 26,700 to 9,100 mg/L by batch fermentation with mixed cultures in an aerated 10-L fermenter. The SCP products, with a crude protein content of 46.09 % (higher than soybean meal), were found palatable and safe for mice. During the treatment process, the microbial community was analyzed using the terminal restriction fragment length polymorphism for bacterial 16S rRNA genes. The results of the analysis suggested that Curacaobacter/Pseudoalteromonas and Paenibacillus/Bacillus were the main microorganisms in treating potato starch processing wastes. The 150-m(3)-scale fermentation demonstrated a potential for treatment in industrial applications. Fermentation of potato pulp and wastewater without adding an extra nitrogen source was a novel approach in treating the potato starch processing waste.

In situ laccase treatment enhances the fermentability of steam-exploded wheat straw in SSCF processes at high dry matter consistencies

This work evaluates the in situ detoxification of inhibitory lignocellulosic broths by laccases to facilitate their fermentation by the xylose-consuming Saccharomyces cerevisiae F12. Treatment of wheat straw slurries with laccases prior to SSCF processes decreased the total phenolic content by 50-80%, reducing the lag phase and increasing the cell viability. After laccase treatment, a negative impact on enzymatic hydrolysis was observed. This effect, together with the low enzymatic hydrolysis yields when increasing consistency, resulted in a decrease in final ethanol yields. Furthermore, when using high substrate loading (20% DM (w/v)), high concentration of inhibitors prevailed in broths and the absence of an extra nitrogen source led to a total cell growth inhibition within the first 24h in non-treated samples. This inhibition of growth at 20% DM (w/v) was overcome by laccase treatment with no addition of nitrogen, allowing S. cerevisiae F12 to produce more than 22 g/L of ethanol.

Preparation of Chaga Medicinal Mushroom, Inonotus obliquus−Fermented Rice Using Solid-State Fermentation and its Taste Quality and Antioxidant Property

Chaga medicinal mushroom, Inonotus obliquus (Pers.:Fr.) Pilat, was inoculated into cooked embryo rice and the mycelial growth in I. obliquus-fermented embryo rice (IER) was monitored. Besides, nonvolatile taste components and antioxidant properties of fruiting bodies, mycelia, IER, and embryo rice were studied. The optimal conditions for mycelial growth were determined to be: 30°C, an inoculation rate of 1 mL/15 g, water supplementation of 60%, and no extra nitrogen source added. IER showed similar proximate composition to embryo rice but contained a substantial amount of ergothioneine (101 mg/kg dry weight). IER contained higher amounts of soluble sugars and polyols, and umami taste components, including monosodium glutamate (MSG)-like components and flavor 5'-nucleotides, than embryo rice. Besides, IER showed a second level of equivalent umami concentrations (223.73 g MSG/100 g). Fruiting bodies did not contain umami components but showed the most effective antioxidant properties. Although some of EC50 values of IER were less than those of mycelia and embryo rice, IER still showed effective antioxidant properties. Based on the results obtained, IER will be a novel functional food.

English

&nbsp; Beauveria bassiana&nbsp;a natural soil borne insect pathogen is being used effectively these days in integrated pest management system.&nbsp;Foliar application of these fungi is quite satisfactory as it invades its host by adhering to insect cuticles through the formation of penetration structures called appresoria, which produces various extracellular enzymes, including chitinase that causes the insect cuticle breaching. Although many investigations have been done in this regard, only a little is known about the induction and repression mechanism of this hydrolytic enzyme. This report illustrates the effect of two carbon sources; colloidal chitin and dextrose and a nitrogen source, yeast extract on the chitinase production of seventeen&nbsp;B. bassiana&nbsp;isolates. The chitinase activity varied among the isolates and the different media studied. A high enzymatic activity was observed in the medium with colloidal chitin as a sole source of carbon followed by the medium containing an extra nitrogen&nbsp;source, yeast extract. Exochitinase activity and the chitinase activity gel were also determined for the isolates showing high chitinase enzyme activity. An array of chitinase isozymes were observed on chitinase activity gel with a common 70 kDa enzyme for all the isolates. &nbsp; Keywords:&nbsp;Beauveria bassiana, induction, colloidal chitin, chitinase, exochitinase.