Enzymatic production of N-acetyl-D-glucosamine by solid state fermentation of chitinase by Penicillium ochrochloron MTCC 517 using agricultural residues

The optimization studies for production of chitinase were carried out by response surface methodology (RSM) based on statistics experimental design using three substrates, which were wheat, rice and red gram bran. 2⁴ full factorial central composite design was applied to evaluate optimal combinations of variables. These variables were chitin concentration, initial moisture content, inoculum level, and incubation time. The results of second order polynomial showed that all four variables had significant effect on chitinase production. Maximum chitinase activity was recorded for wheat bran (2443.23 U g⁻¹) than rice (1216.65 U g⁻¹) and red gram bran (961.32 U g⁻¹). An overall 3-fold increase in chitinase activity was achieved using optimized strategies of RSM. Growth of the fungus on all bran particles have been visualized by scanning electron microscopy. These results indicated the potential of Penicillium ochrochloron for economical production of chitinase using agricultural residues. TLC and HPLC analysis of colloidal chitin hydrolysate with partially purified chitinases revealed that the major reaction product was monomeric GlcNAc indicating the potential of these enzymes for efficient production of GlcNAc.     

Use of chitin measurement to estimate fungal biomass in solid state fermentation

Twenty-two strains of twelve species of Deuteromycotina: Hyphomycetes were studied. Most of them had a variable glucosamine amount (standard deviation higher than 5%). However, if we consider that the amount of glucosamine is constant, the accuracy of the method remains satisfactory (10% instead of 5%, which is the accuracy of the chitin hydrolysis and colorimetric glucosamine measurement). So, by means of this measurement, the fungal growth kinetics could be followed on different solid media (vegetable material such as sugar beet pulp and sponge or mineral like clay granules) used. It is important to note that this method should not be used to compare different media without calibration.     

Fungal decomposition of oat straw during liquid and solid state fermentation

White rot fungi (Coriolus hirsutus, Coriolus zonatus, and Cerrena maxima from the collection of the Komarov Botanical Institute of the Russian Academy of Sciences) and filamentous fungi (Mycelia sterilia INBI 2-26 and Trichoderma reesei 6/16) were grown on oat straw-based liquid and solid media, as well as in a bench-scale reactor, either individually or as co-cultures. All fungi grew well on solid agar medium supplemented with powdered oat straw as the sole carbon source. Under these conditions, the mould Trichoderma reesei fully suppressed the growth of all basidiomycetes studied; conversely, Mycelia sterilia neither affected the development of any of the cultures, nor did it show any substantial susceptibility to suppression by their presence. Pure solid cultures of basidiomycetes, as well as the co-culture of Coriolus hirsutus and Cerrena maxima caused a notable bleaching of the oat straw during its consumption. When grown on the surface of oat straw-based liquid medium, the basidiomycetes consumed up to 40% polysaccharides without measurable lignin degradation (a concomitant process). Under these conditions, Mycelia sterilia decomposed no more than 25% lignin in 60 days, but this was observed only after polysaccharide exhaustion and biomass accumulation. In contrast, during solid state straw fermentation, white rot fungi consumed up to 75% cellulose and 55% lignin in 83 days (C. zonarus), whereas the corresponding consumption levels for co-cultures of Mycelia sterilia and Trichoderma reesei equaled 70 and 45%, respectively (total loss of dry weight ranged from 55 to 60%). Carbon dioxide-monitored solid-state fermentation of oat straw by the co-culture of filamentous fungi was successfully performed in an aerated bench-scale reactor.     

Potential of solid state fermentation for production of ergot alkaloids

Production of total ergot alkaloids by Claviceps fusiformis in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of Claviceps purpurea but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids.     

樟绒枝霉(Malbranchea cinnamomea)固体发酵产木聚糖酶的发酵条件优化

[目的] 研究樟绒枝霉(Malbranchea cinnamomea) CAU521利用农业废弃物固体发酵产木聚糖酶的发酵条件.[方法]采用单因素试验法优化影响菌株产酶的各个条件,包括碳源种类、氮源种类、初始pH、初始水分含量、培养温度及发酵时间共6个因素.[结果]获得的最佳产酶条件为:稻草为发酵碳源、2％(W/W)的酵母提取物为氮源、初始pH 7.0、初始水分含量80％和发酵温度45℃.在此条件下发酵6d后木聚糖酶的酶活力达到13 120 U/g干基碳源.[结论]樟绒枝霉固体发酵产木聚糖酶的产酶水平高,生产成本低,具有潜在的工业化应用前景.     

黑曲霉固态发酵生产单宁酶的条件优化

研究采用响应面法优化黑曲霉固态发酵生产单宁酶的培养条件。应用Plackett—Burman试验筛选出重要影响因子：五倍子粉含量、（NH4）2SO4浓度以及接种孢子量,最陡爬坡试验逼近最大响应区域。应用Box．Behnken响应面试验对重要影响因子进一步优化。得到最佳培养条件：每250mL三角瓶中装入1．0g五倍子粉、4．4g稻壳和0．5g麸皮、液固比（mL／g）2：1且营养盐溶液组成为（NH4）2s0421g/L、MgSO4·7H2O1g／L、NaCl1g／L,培养基pH自然,接种5．7×10^7个孢子后在30℃温度下培养4d。在此条件下,单宁酶产量从40U／g提高到114U／g,3次重复验证性试验平均值为115U／g,验证了模型的可靠性。     

Studies on catabolite repression in solid state fermentation for biosynthesis of fungal amylases

Catabolite repression by glucose of the biosynthesis of alpha amylase and amyloglucosidase by Aspergillus niger CFTRI 1105 was studied in a solid state fermentation (SSF) and in submerged fermentation (SMF) systems and the results were compared. The addition of glucose did not enhance the production of alpha-amylase and amyloglucosidase in an earlier fermentation system. However, a drastic reduction in alpha-amylase production was observed in submerged fermentation by the addition of 5·0 mg ml⁻¹ glucose and of amyloglucosidase production by 10 mg ml⁻¹ glucose. Glucose concentrations above 50 mg ml⁻¹ completely suppressed the production of both enzymes in the initial hours. In contrast, in the SSF system the repression was negligible, even when the glucose level was raised to 150 mg g⁻¹ wheat bran for both alpha and amyloglucosidase synthesis.     

Anaerobic solid state fermentation of cellulosic substrates with possible application to cellulase production

Summary A solid state fermentation process was developed for the conversion of straw and cellulose under anaerobic conditions by a mixed culture of cellulolytic and methanogenic organisms. The bioconversion rate and efficiency were compared under mesophilic (35° C) and thermophilic (55° C) conditions. Cellulolytic activity was assayed in terms of sugar and overall soluble organic matter (chemical oxygen demand, COD) production. Maximum conversion rates were obtained under thermophilic conditions, i.e. 8.4 g and 14.2 g COD/kg·d, respectively, when wheat straw and cellulose were used as substrates. The cellulolytic activity of the reactor contents (23% dry matter), measured under substrate excess conditions, amounted to 50 g COD/kg·d. As a comparison, the activity of rumen contents (15% dry matter) measured by the same assay amounted to 150 g COD/kg·d. The anaerobic cellulases appeared to be substrate bound. This and the relative low activity levels attained, limit the perspectives of producing cellulase enzymes by this type of process.     

Cellulase production by solid state fermentation on lignocellulosic waste from the xylose industry

Cellulase production was carried out by solid state fermentation using corncob residue, a lignocellulosic waste from the xylose industry, as the substrate of Trichoderma reesei ZU-02. The effects of water content, dosage of wheat bran and initial pH value in solid substrate on cellulase synthesis were studied in shallow tray fermentors. The solid substrate could be reused in at least three batches and the highest cellulase activity (158 IFPU/g koji) was obtained in the second fermentation batch. To produce cellulase on a larger scale, a deep trough fermentor with forced aeration was used and 128 IFPU/g koji (305 IFPU/g cellulose) was reached after 5 days solid state fermentation. The enzyme koji produced in the present process can be used directly to hydrolyze corncob residue effectively, when the cellulase dosage was above 20 IFPU/g substrate, the saccharification yield could be over 84%.     

Economic production of Lysinibacillus sphaericus under solid state fermentation

A highly active mosquitocidal Lysinibacillus sphaericus namely Ls 9B24 was isolated from soil of Alexandria governorate in Egypt. It was more active than the standard strain, L. sphaericus 2362. The sporulation and toxin formation of both cultures grown on different leguminous seeds and by-products under solid state fermentation (SSF) were studied. Among the tested substrates, 6% cotton seed meal enhanced sporulation and the mosquitocidal activity of L. sphaericus 2362, while 6% fodder yeast enhanced sporulation and the mosquitocidal activity of Ls 9B24. The optimum SSF growth conditions for maximum mosquitocidal activity by both cultures were using coarse wheat bran as a carrier material, 50% initial moisture content, 4–64 × 10⁶ colony forming units (CFU)/g solid medium inoculum and 6 days’ incubation period at 30°C. Addition of 0.5% yeast extract enhanced toxicity about 2.2 and 1.8 fold for L. sphaericus 2362 and Ls 9B24, respectively.     

Lipase production from an alkalophilic yeast sp. by solid state fermentation

The present investigation has been carried out with the aim to produce lipase from an alkalophilic yeast species by solid state fermentation using rice and wheat brans as alternative cheap solid substrates.     

Culture requirements for the production of protease by Aspergillus oryzae in solid state fermentation

Summary A number of culture conditions for protease production by Aspergillus oryzae NRRL 2160 on solid substrates were investigated. The pH of the medium and the substrate markedly affected protease production. High protease yield was obtained when the fungus was cultivated for 72–96 h on rice hulls: rice bran (7:3), at an initial pH of 7.0. Maximal protease production was achieved at an initial moisture content of 35–40%, corresponding to a water activity range of 0.982–0.986. Casein and gluten were effective inducers. Polyethylene bags proved to be promising containment systems for solid state cultivation. Offprint requests to: A. M. R. Pilosof     

A mathematical approach for the estimation of biomass production rate in solid state fermentation

The oxygen uptake rate (OUR) was studied in a solid state fermentation process of dried citrus peel with the strain Aspergillus niger QH-2 in order to obtain the growth estimation of the microorganism in the system. The relationship between OUR, the maintenance coefficient (m) and the yield for oxygen consumption Y_O2 allows the estimation of the biomass rate if we consider that both parameters are not constants in some periods of the process. It was estimated that in the first 24th the strain has an specific growth rate of 0.174 h^?1 with values for Y_O2 and m in the order of 2.84 g-cell/g-oxygen and 0.006 g-oxygen/g-cell ·h respectively.     

Mixed substrate solid state fermentation for production and extraction of lipase from Aspergillus niger MTCC 2594

A novel mixed substrate solid-state fermentation (SSF) process has been developed for Aspergillus niger MTCC 2594 using wheat bran (WB) and gingelly oil cake (GOC) and the results showed that addition of GOC to WB (WB : GOC, 3 : 1, w/w) increased the lipase activity by 36.0% and the activity was 384.3+/-4.5 U/g dry substrate at 30 degrees C and 72 h. Scale up of lipase production to 100 g and 1 kg tray-level batch fermentation resulted in 95.0% and 84.0% of enzyme activities respectively at 72 h. A three-stage multiple contact counter-current extraction yielded 97% enzyme recovery with a contact time of 60 min. However, extraction by simple percolation and plug-flow methods resulted in decreased enzyme recoveries. The mixed substrate SSF process has resulted in a significant increase in specific activity (58.9%) when compared to a submerged fermentation (SmF) system. Furthermore, an efficient process of extraction has been standardized with this process. Use of GOC along with WB as potential raw materials for enzyme production could be of great commercial significance. This is the first report on the production and extraction of lipase from Aspergillus niger using mixed solid substrates, WB and GOC, which are potential raw materials for the production of enzymes and other value-added products.     

Extracellular xylanase production by Fusarium species in solid state fermentation

Fusarium sp. has been shown to be a promising organism for enhanced production of xylanases. In the present study, xylanase production by 21 Fusarium sp. isolates (8 Fusarium culmorum, 4 Fusarium solani, 6 Fusarium verticillioides and 3 Fusarium equiseti) was evaluated under solid state fermentation (SSF). The fungal isolate Fusarium solani SYRN7 was the best xylanase producer among the tested isolates. The effects of some agriculture wastes (like wheat straw, wheat bran, beet pulp and cotton seed cake) and incubation period on xylanase production by F. solani were optimized. High xylanase production (1465.8 U/g) was observed in wheat bran after 96 h of incubation. Optimum pH and temperature for xylanase activity were found to be 5 and 50 degrees C, respectively.     

Potential of fed-batch culture in solid state fermentation for production of gibberellic acid

Summary Fed-batch culture technique, applied to the solid state fermentation process for the production of gibberellic acid, improves the yield by 18.2% as compared to a conventional batch solid state fermentation.     

Optimization of protease production from Bacillus halodurans under solid state fermentation using agrowastes

Marine microbes are potential source for novel metabolites. They are efficient in producing these metabolites utilizing agrowastes. Protease is one of the enzymes which find wide industrial applications. In the present study, protease producing bacteria was isolated from marine sediments and the organism was identified as Bacillus halodurans. The organism was subjected to protease production under solid state fermentation (SSF) using different agrowastes as substrates. Among the substrates used, wheat bran yielded maximum quantity of protease. The fermentation process was carried out under different cultural conditions to optimize the parameters influencing the enzyme production. The results of the stain removal studies by the enzyme revealed the increased efficiency of the microbial enzyme than the commercial detergent.     

A pilot process of solid state fermentation from sugar beet pulp for the production of microbial protein

The bioconversion of sugar beet pulp (SBP) into microbial protein by the process of solid state fermentation (SSF) was studied. Two SSF reactors (each having overall dimensions of 17.6 × 3.6 × 2.0 m) with appropriate control systems were constructed. This pilot plant has a maximum working capacity of 50 metric tons (20% dry metter). The production strain used was Aspergillus tamarii 827, which was isolated by our laboratory. The protein content of the products amounted to 22.4% in 48 h.     

Utilisation of fruits waste for citric acid production by solid state fermentation

A solid state fermentation method was used to utilise pineapple, mixed fruit and maosmi waste as substrates for citric acid production using Aspergillus niger DS 1. Experiments were carried out in the presence and absence of methanol at different moisture levels. In the absence of methanol the maximum citric acid was obtained at 60% moisture level whereas in the presence of methanol the maximum citric acid was obtained at 70% moisture level. The stimulating effect of methanol was less at lower moisture level. The inhibitory effect of metal ions was also not observed and maximum citric acid yield of 51.4, 46.5 and 50% (based on sugar consumed) was obtained from pineapple, mixed fruit and maosmi residues, respectively.     

Microbial production of gallic acid by modified solid state fermentation

Bioconversion of tannin to gallic acid from powder of teri pod (Caesalpinia digyna) cover was achieved by the locally isolated fungus, Rhizopus oryzae, in a bioreactor with a perforated float for carrying solid substrate and induced inoculum. Modified Czapek-Dox medium, put beneath the perforated float, with 2% tannic acid at pH 4.5, temperature 32°C, 93% relative humidity, incubated for 3 days with 3-day-old inoculum was optimum for the synthesis of tannase vis-à-vis gallic acid production. Conversion of tannin to gallic acid was 90.9%. Diethyl ether was used as the solvent for extraction of gallic acid from the fermented biomass. Received 14 December 1998/ Accepted in revised form 17 June 1999