Utilization of oil palm decanter cake for cellulase and polyoses production

The abundance of oil palm decanter cake (OPDC) is a problem in oil palm mills. However, this lignocellulosic biomass can be utilized for cellulase and polyoses production. The effectiveness of chemical and physical pretreatment in reducing the lignin content was studied by saccharification using a Celluclast 1.5 L and scanning electron microscope. Physicochemical pretreatment of OPDC with 1% (w/v) NaOH and autoclaving at 121°C for 20 min increased potential polyoses produced to 52.5% and removed 28.7% of the lignin content. The optimized conditions for cellulase production by a locally isolated fungus were a time of 120 h, a substrate of untreated OPDC, a spore concentration of 1 × 10⁷ spore/mL, a temperature of 30°C, and a pH between 7.0 and 7.5. Trichoderma asperellum UPM1 produced carboxymethylcellulase (CMCase), ??-glucosidase and filter paper activity (FPase) in the following concentrations: 17.35, 0.53, and 0.28 U/mL, respectively. Aspergillus fumigatus UPM2 produced the CMCase, ??-glucosidase and FPase in the following amounts: 10.93, 0.76, and 0.24 U/mL. The cellulases from T. asperellum UPM1 produced 2.33 g/L of polyoses and the cellulases from A. fumigatus UPM2 produced 4.37 g/L of polyoses.     

Optimization of cellulase production by a brown rot fungus Fomitopsis sp. RCK2010 under solid state fermentation

Culture conditions for enhanced cellulase production from a newly isolated brown rot fungus, Fomitopsis sp. RCK2010 were optimized under solid state fermentation. An initial pH of 5.5 and moisture ratio of 1:3.5 (solid:liquid) were found to be optimal for maximum enzyme production. Of the different carbon sources tested wheat bran gave the maximum production of CMCase (71.526 IU/g), FPase (3.268 IU/g), and β-glucosidase (50.696 IU/g). Among the nitrogen sources, urea caused maximum production of CMCase (81.832 IU/g), where as casein and soyabean meal gave the highest FPase (4.682 IU/g) and β-glucosidase (69.083 IU/g) production, respectively. Among amino acids tested glutamic acid gave the highest production for CMCase (84.127 IU/g); however 4-hydroxy-l-proline stimulated maximum FPase production (6.762 IU/g). Saccharification of pretreated rice straw and wheat straw by crude enzyme extract from Fomitopsis sp. RCK2010 resulted in release of 157.160 and 214.044 mg/g of reducing sugar, respectively.     

Comprehensive studies on optimization of cellulase and xylanase production by a local indigenous fungus strain via solid state fermentation using oil palm frond as substrate

The high cost of cellulases remains the most significant barrier to the economical production of bio-ethanol from lignocellulosic biomass. The goal of this study was to optimize cellulases and xylanase production by a local indigenous fungus strain (Aspergillus niger DWA8) using agricultural waste (oil palm frond [OPF]) as substrate. The enzyme production profile before optimization indicated that the highest carboxymethyl cellulose (CMCase), filter paper (FPase), and xylanase activities of 1.06 U/g, 2.55 U/g, and 2.93 U/g were obtained on day 5, day 4, and day 5 of fermentation, respectively. Response surface methodology was used to study the effects of several key process parameters in order to optimize cellulase production. Of the five physical and two chemical factors tested, only moisture content of 75% (w/w) and substrate amount of 2.5 g had statistically significant effect on enzymes production. Under optimized conditions of 2.5 g of substrate, 75% (w/w) moisture content, initial medium of pH 4.5, 1 × 10⁶ spores/mL of inoculum, and incubation at ambient temperature (±30°C) without additional carbon and nitrogen, the highest CMCase, FPase, and xylanase activities obtained were 2.38 U/g, 2.47 U/g, and 5.23 U/g, respectively. Thus, the optimization process increased CMCase and xylanase production by 124.5 and 78.5%, respectively. Moreover, A. niger DWA8 produced reasonably good cellulase and xylanase titers using OPF as the substrate when compared with previous researcher finding. The enzymes produced by this process could be further use to hydrolyze biomass to generate reducing sugars, which are the feedstock for bioethanol production.     

Utilization of pretreated coir pith for the optimized bioproduction of cellulase by Aspergillus nidulans

The present study is aimed at simultaneous cellulase synthesis and coir pith degradation by Aspergillus nidulans using coir pith as chief substrate. The lignocellulosic biomass, coir pith is known to be an excellent carbon source for microbial cellulase production under solid state fermentation. The alkali pretreatment with sodium hydroxide was seen to enhance enzymatic hydrolysis. The effect of coir pith weight, moisture content, initial pH and growth temperature on cellulase activity and yield were investigated by response surface methodology (RSM) employing a four-factor-five-level central composite design (CCD). The results of Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and Scanning electron microscopy (SEM) of coir pith showed structural changes through pretreatment, in favor of enzymatic hydrolysis. Maximum carboxy methyl cellulase activity (CMCase) of 28.64 U/g and cellulase yield of 66.32% were achieved with 8 g coir pith at 70% moisture content and 40 °C temperature with pH 5 as evident from run numbers 25 and 30. Filter paper (FPase) and cellobiase (CBase) activities of 10.23 U/g and 4.31 U/g respectively were observed on the 11th day after the inoculation.     

γ-ray induced mutagenesis ofCellulomonas biazotea for improved production of cellulases

A rifampin-resistant mutant ofCellulomonas biazotea secreted elevated levels of cellulasesin vivo. The cellulase production in the mutant was not inhibited in the presence of 5% glucose, cellobiose or glycerol in the solid medium. The mutant exhibited approximately two- to three-fold enhanced product yields and productivity of cellular β-glucosidase over the wild parent in shake-flask culture studies when grown on either cellulosic or lignocellulosic substrates. Extracellular production of filter paper cellulase (FPase) and endo-glucanase (CMCase) were also significantly (p≤0.05) altered. During growth of the mutant on α-cellulose, the maximum volumetric productivities for CMCase, FPase and β-glucosidase were 52, 23.3, and 15.2 IUL⁻¹ h⁻¹,i.e 118, 121, and 229% their respective values for the parental strain. Some enzyme properties of the mutant cellulases were altered. Mutant-derived cellulases produced higher yields of glucose arising by degradation of bagasse, wheat straw, and α-cellulose (1.53-, 1.57-, and 1.75-fold, respectively).     

Production of cellulases and xylanase by Aspergillus fumigatus SK1 using untreated oil palm trunk through solid state fermentation

Direct utilization of untreated oil palm trunk (OPT) for cellulases and xylanase production by Aspergillus fumigatus SK1 was conducted under solid-state fermentation (SSF). The highest activities of extracellular cellulases and xylanases were produced at 80% moisture level, initial pH 5.0, 1 × 10⁸ spore/g (inoculum) with 125 μm of OPT as sole carbon source. The cellulases and xylanase activities obtained were 54.27, 3.36, 4.54 and 418.70 U/g substrates for endoglucanase (CMCase), exoglucanase (FPase), β-glucosidase and xylanase respectively. The crude cellulases and xylanase required acidic condition to retain their optimum activities (pH 4.0). Crude cellulases and xylanase were more stable at 40 °C compared to their optimum activities conditions (60 °C for FPase and 70 °C for CMCase, β-glucosidase and xylanase). SDS-PAGE and zymogram analysis showed that Aspergillus fumigatus SK1 could secrete cellulases (endoglucanase, exoglucanase and β-glucosidase), xylanase and protease. Enzymatic degradation of alkaline treated OPT with concentrated crude cellulases and xylanases resulted in producing polyoses.     

Effect of Host Diet and Hindgut Microbial Composition on Cellulolytic Activity in the Hindgut of the American Cockroach, Periplaneta americana

Cellulase activity measured as filter paper digesting activity (FPase) and carboxymethyl cellulase (CMCase) was demonstrated in hindgut extracts of the cockroach Periplaneta americana. The highest activities measured amounted to 0.89 and 0.12 U · ml^-1 for CMCase and FPase, respectively. The cellulolytic capacity of the hindgut population increased dramatically when protozoa were present, and the activities were found to vary depending on the feeding regimen. Cellulose-rich diets induced high protozoal numbers, resulting in a high cellulase activity. A close correlation was found between the number of Nyctotherus ovalis organisms, the major protozoans in the hindgut, and both FPase and CMCase activity. Since the numbers of this protozoan also correlated with the methane production of the insect, it appears that N. ovalis is responsible for the major part of cellulolytic and methanogenic activity found in the hindgut of P. americana.     

Optimization of pretreatment and fermentation conditions for production of extracellular cellulase complex using sugarcane bagasse

Sugarcane bagasse (SCB), a lignocellulosic byproduct of juice extraction from sugarcane, is rich in cellulose (40-42%). This could be used as a substrate for the production of cellulase complex. Fermentation conditions were optimized for production of cellulase complex (CMCase, Cellulobiase and FPase) by wild type Trichoderma sp. using sugarcane bagasse as sole carbon source. Alkaline treatment (2% NaOH) of bagasse (AlSCB) was found suitable for the production of reducing sugar over the acidic pretreatment method. After 5 days of incubation period, 5% substrate concentration at pH 5.0 and 400C resulted in maximum production of CMCase (0.622 U), while maximum (3.388 U) production of cellulobiase was obtained at 300C. The CMCase was precipitated and purified to the extent of 59.06 fold by affinity chromatography with 49.09% recovery. On 12% SDS-PAGE, a single band corresponding to 33 kDa was observed. The Km and Vmax for CMCase from Trichoderma was found 507.04 mg/ml and 65.32 mM/min, respectively. The enzyme exhibited maximum activity at 300C at pH-5.0 (0.363 U) and was stable over range of 20-60°C and pH 5.0-7.5.     

Biodegradation of lignocellulosic waste by Aspergillus terreus

Biodegradation of lignocellulosic waste by Aspergillus terreus is reported for the first time. This isolate produced 250 CMCase (carboxymethyl cellulase or endoglucanase) U.ml^-1 and biodegraded hay and straw during 3 days and the biomass production on straw was 5g.L^-1dry weight from 0.25 cm² inoculated mycellium. This strain secreted endocellulases and exocellulases in the culture medium, but some of the enzymes produced, remained cell membrane bound. Cell bound enzymes were released by various treatments. The highest amount of endoglucanase and exoglucanase was released when the cells were treated with sonication. Aspergillus terreus was added to two tanks containing sugar wastewater and pulp manufacturing waste, as a seed for COD removal. This fungus reduced the COD by 40–80 percent, also, ammonia was reduced from 14.5 mM to 5.6 mM in sugar beet wastewater. The effects of crude enzyme of this fungus for COD removal was studied.     

Strain improvement of <Emphasis Type="Italic">Trichoderma reesei</Emphasis> Rut C-30 for increased cellulase production

The strain of Trichoderma reesei Rut C-30 was subjected to mutation after treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NG) for 6 h followed by UV irradiation for 15 min. Successive mutants showed enhanced cellulase production, clear hydrolysis zone and rapid growth on Avicel-containing plate. Particularly, the mutant NU-6 showed approximately two-fold increases in activity of both FPA and CMCase in shake flask culture when grown on basal medium containing peptone (1%) and wheat bran (1%). The enzyme production was further optimized using eight different media. When a mixture of lactose and yeast cream was used as cellulase inducer, the mutant NU-6 yielded the highest enzyme and cell production with a FPase activity of 6.2 U ml⁻¹, a CMCase activity of 54.2 U ml⁻¹, a β-glucosidase activity of 0.39 U ml⁻¹, and a fungal biomass of 12.6 mg ml⁻¹. It deserved noting that the mutant NU-6 also secreted large amounts of xylanases (291.3 U ml⁻¹). These results suggested that NU-6 should be an attractive producer for both cellulose and xylanase production.     

Cost-effective production of cellulose hydrolysing enzymes from <Emphasis Type="Italic">Trichoderma</Emphasis> sp. RCK65 under SSF and its evaluation in saccharification of cellulosic substrates

Trichoderma sp. is a potential cellulase producing mesophilic fungi which grow under mild acidic condition. In this study, growth and nutritional conditions were manipulated for the maximum and cost-effective production of cellulase using lab strain Trichoderma sp. RCK65 and checked for its efficiency in hydrolysis of Prosopis juliflora (a woody substrate). Preliminary studies suggested that when 48 h old secondary fungal culture (20 % v/w) was inoculated in wheat bran moistened with mineral salt solution (pH 4.5 and 1:3 solid to moisture ratio), incubated at 30 °C and after 72 h, it produced maximum cellulase (CMCase 145 U/gds, FPase 38 U/gds and β-glucosidase 105 U/gds). However, using statistical approach a S:L ratio (1:1) was surprisingly found to be optimum that improved cellulase that is CMCase activity by 6.21 %, FPase activity by 23.68 % and β-glucosidase activity by 37.28 %. The estimated cost of crude enzyme (Rs. 5.311/1000 FPase units) seems to be economically feasible which may be due to high enzyme titre, less cultivation time and low media cost. Moreover, when the crude enzyme was used to saccharify pretreated Prosopis juliflora (a woody substrate), it resulted up to 83 % (w/w) saccharification.     

Cellulolytic enzyme production from agricultural residues for biofuel purpose on circular economy approach

This study evaluated the production of cellulolytic enzymes from different agricultural residues. The crude enzyme extract produced was characterized and applied for saccharification of some agricultural residues. Maximum cellulolytic activities were obtained using soybean hulls. All enzymatic activities were highly stable at 40 °C at a pH range of 4.5–5.5. For stability at low temperatures, the enzyme extract was stored at freezing temperature and cooling for about 290 days without major loss of activity. The K_m values found for total cellulase (FPase), endoglucanase (CMCase), and xylanase were 19.73 mg ml⁻¹, 0.65 mg ml⁻¹, and 22.64 mg ml⁻¹, respectively, and V_max values were 0.82 mol min⁻¹ mg⁻¹, 0.62 mol min⁻¹ mg⁻¹, and 104.17 mol min⁻¹ mg⁻¹ to cellulose, carboxymethyl cellulose, and xylan, respectively. In the saccharification tests, the total amount of total reducing sugars (TRS) released from 1 g of soybean hulls catalyzed by the enzymes present in the crude enzyme extract was 0.16 g g⁻¹ dry substrate.

     

Production,purification and characterization of a novel GH 12 family endoglucanase from Aspergillus terreus and its application in enzymatic degradation of delignified rice straw

Endoglucanase production was carried out using in-house isolate Aspergillus terreus on rice straw under solid state fermentation. An increase of 1.25-fold endoglucanase production was obtained under optimized conditions using response surface methodology. The enzyme was purified to homogeneity by gel filtration chromatography. Its molecular weight was determined as 28.18 kDa by gel filtration and 29.13 kDa on SDS-PAGE. The enzyme displayed maximum activity at 50 °C and pH 4.8. It was stable for 240 min at 50 °C and 120 min at 60 °C but rapidly inactivated at 70 °C. The purified enzyme was specific towards carboxymethyl-cellulose but showed no activity for cellobiose or xylan. Maximum velocity (V_max) and K_M were 16.15 μmol min⁻¹ mg⁻¹ and 12.01 mg ml⁻¹, respectively. AgNO₃, KCl, NaCl, and MnSO₄ were found to inhibit enzyme activity while CaCl₂ and ZnSO₄ activated the enzyme. Internal peptide mass fingerprinting analysis identified that the protein belongs to GH12 superfamily endoglucanases. External supplementation of the purified enzyme to the crude cellulase showed 38.7% increase in saccharification efficiency of the delignified rice straw compared to the crude cellulase alone. The results demonstrated that the addition of GH 12 family purified endoglucanase to the crude cellulase can efficiently convert lignocellulosic biomass to fermentable sugars.     

Characterization of a recombinant thermostable β-glucosidase from Putranjiva roxburghii expressed in Saccharomyces cerevisiae and its use for efficient biomass conversion

A β-glucosidase gene from Putranjiva roxburghii (PRGH1) was heterologously expressed in Saccharomyces cerevisiae to enable growth on cellobiose. The recombinant enzyme was secreted to the culture medium, purified and biochemically characterized. The enzyme is a glycoprotein with a molecular weight of ∼68 kDa and exhibited enzymatic activity with β‐linked aryl substrates like pNP-Fuc, pNP-Glc, pNP-Gal and pNP-Cel with catalytic efficiency in that order. Significant enzyme activity was observed for cellobiose, however the enzyme activity was decreased with increase in chain length of glycan substrates. Using cellobiose as substrate, the enzyme showed optimal activity at pH 5.0 and 65 °C. The enzyme was thermostable up to 75 °C for 60 min. The enzyme showed significant resistance towards both glucose and ethanol induced inhibition. The recombinant S. cerevisiae strain showed advantages in cell growth, glucose and bio-ethanol production over the native strain with cellobiose as sole carbon source. In simultaneous saccharification and fermentation (SSF) experiments, the recombinant strain was used for bio-ethanol production from two different cellulosic biomass sources. At the end of the SSF, we obtained 9.47 g L⁻¹ and 14.32 g L⁻¹ of bio-ethanol by using carboxymethyl cellulose and pre-treated rice straw respectively. This is first report where a β-glucosidase gene from plant origin has been expressed in S. cerevisiae and used in SSF.     

Double Mutants of Cellulomonas biazotea for Production of Cellulases and Hemicellulases following Growth on Straw of a Perennial Grass

Summary Deoxyglucose-resistant mutants of Cellulomonas biazotea secreted elevated levels of cellulases and xylanases. The production of β-glucosidase in the constitutive mutant was increased 5-fold over its parent strain. This mutant showed an approximately 1.6-fold enhanced productivity of extracellular endo-glucanase following growth on Leptochloa fusca over the mutant parent. Extracellular production of xylanase, filter-paper cellulase (FPase) and endo-glucanase (CMCase) were also altered in the mutant. Maximum volumetric productivities for xylanase, β-xylosidase, FPase, β-glucosidase and endo-glucosidase were 451, 98, 80, 95, and 143 IU l⁻¹ h⁻¹ which were significantly more than their respective values from the parental strains. The enzyme preparation of the mutants exhibited improved saccharification of kallar grass straw.     

Domestic wastewater as substrate for cellulase production by Trichoderma harzianum

Cellulase production using residues as substrate has been well described, as it is an interesting method of reducing the costs of processes, one of the main bottlenecks for the production of enzymes. This research describes for the first time the use of raw domestic wastewater, which is largely and continuously generated, as a culture base medium for cellulase production. The strain Trichoderma harzianum HBA03 was selected according to the highest activity produced for FPase (5.4 U/mL) and CMCase (8.2 U/mL). Peptone was selected as a nitrogen source and microcrystalline cellulose as the inducer for cellulase production, resulting in FPase activities of 5.6 and 5.0 U/mL and CMCase activities of 12.0 and 14.4 U/mL. The use of domestic wastewater as the culture medium led to an increase of 1.41 and 1.14 fold of FPase and CMCase production, respectively, compared to the synthetic medium. Production was also carried out in a bubble column reactor in which the maximum productivities achieved 10.2 U/L.h (FPase) and 64.6 U/L.h (CMCase). The presented results demonstrate the feasibility of the use of domestic wastewater for cellulases production, thereby contributing to the development of a sustainable process for reusing wastewater with a significant reduction in environmental impact.     

Plant growth-promoting traits of epiphytic and endophytic yeasts isolated from rice and sugar cane leaves in Thailand

A total of 1035 yeast isolates, obtained from rice and sugar cane leaves, were screened primarily for indole-3-acetic acid (IAA) production. Thirteen isolates were selected, due to their IAA production ranging from 1.2 to 29.3 mg g⁻¹ DCW. These isolates were investigated for their capabilities of calcium phosphate and ZnO₃ solubilisation, and also for production of NH₃, polyamine, and siderophore. Their 1-aminocyclopropane-1-carboxylate (ACC) deaminase, catalase and fungal cell wall-degrading enzyme activities were assessed. Their antagonism against rice fungal pathogens was also evaluated. Strain identification, based on molecular taxonomy, of the thirteen yeast isolates revealed that four yeast species – i.e. Hannaella sinensis (DMKU-RP45), Cryptococcus flavus (DMKU-RE12, DMKU-RE19, DMKU-RE67, and DMKU-RP128), Rhodosporidium paludigenum (DMKU-RP301) and Torulaspora globosa (DMKU-RP31) – were capable of high IAA production. Catalase activity was detected in all yeast strains tested. The yeast R. paludigenum DMKU-RP301 was the best IAA producer, yielding 29.3 mg g⁻¹ DCW, and showed the ability to produce NH₃ and siderophore. Different levels of IAA production (7.2–9.7 mg g⁻¹ DCW) were found in four strains of C. flavus DMKU-RE12, DMKU-RE19, and DMKU-RE67, which are rice leaf endophytes, and strain DMKU-RP128, which is a rice leaf epiphyte. NH₃ production and carboxymethyl cellulase (CMCase) activity was also detected in these four strains. Antagonism to fungal plant pathogens and production of antifungal volatile compounds were exhibited in T. globosa DMKU-RP31, as well as a moderate level of IAA production (4.9 mg g⁻¹ DCW). The overall results indicated that T. globosa DMKU-RP31 might be used in two ways: enhancing plant growth and acting as a biocontrol agent. In addition, four C. flavus were also found to be strains of interest for optimal IAA production.     

Enhanced cellulase production through random mutagenesis of Talaromyces pinophilus OPC4-1 and fermentation optimization

Reducing cellulase cost remains a major challenge for lignocellulose to fuel and chemical industries. In this study, mutants of a novel wild-type cellulolytic fungal strain Talaromyces pinophilus OPC4-1 were developed by consecutive UV irradiation, N-methyl-N`-nitro-N-nitrosoguanidine (NTG) and ethylmethane sulfonate (EMS) treatment. A potential mutant EMM was obtained and displayed enhanced cellulase production. Using Solka Floc cellulose as the substrate, through fed-batch fermentation, mutant strain T. pinophilus EMM generated crude enzymes with an FPase activity of 27.0 IU/mL and yield of 900 IU/g substrate. When corncob powder was used, strain EMM produced crude enzymes with an FPase activity of 7.3 IU/mL and yield of 243.3 IU/g substrate. In addition, EMM crude enzymes contained 29.2 and 16.3 IU/mL β-glucosidase on Solka Floc cellulose and corncob power, respectively. The crude enzymes consequently displayed strong biomass hydrolysis performance. For corncob hydrolysis, without supplement of any commercial enzymes, glucose yields of 591.7 and 548.6 mg/g biomass were obtained using enzymes produced from Solka Floc cellulose and corncob powder, respectively. It was 553.9 mg/g biomass using the commercial enzyme mixture of Celluclast 1.5 L and Novozyme 188. Strain T. pinophilus EMM was therefore a potential fungus for on-site enzyme production in biorefinery processes.     

Cellulases from Penicillium funiculosum: production, properties and application to cellulose hydrolysis

The objective of this work is to investigate the utilization of two abundant agricultural residues in Brazil for the production and application of cellulolytic enzymes. Different materials obtained after pretreatment of sugarcane bagasse, as well as pure synthetic substrates, were considered for cellulase production by Penicillium funiculosum. The best results for FPase (354 U L^?1) and β-glucosidase (1,835 U L^?1) production were observed when sugarcane bagasse partially delignified cellulignin (PDC) was used. The crude extract obtained from PDC fermentation was then partially characterized. Optimal temperatures for cellulase action ranged from 52 to 58°C and pH values of around 4.9 contributed to maximum enzyme activity. At 37°C, the cellulases were highly stable, losing less than 15% of their initial activity after 23 h of incubation. There was no detection of proteases in the P. funiculosum extract, but other hydrolases, such as endoxylanases, were identified (147 U L^?1). Finally, when compared to commercial preparations, the cellulolytic complex from P. funiculosum showed more well-balanced amounts of β-glucosidase, endo- and exoglucanase, resulting in the desired performance in the presence of a lignocellulosic material. Cellulases from this filamentous fungus had a higher glucose production rate (470 mg L^?1 h^?1) when incubated with corn cob than with Celluclast^®, GC 220^® and Spezyme^® (312, 454 and 400 mg L^?1 h^?1, respectively).     

一株产纤维素酶嗜盐真菌的分离、鉴定及发酵条件优化

纤维素酶是生物燃料产业的关键酶系。本文通过刚果红染色法从腌制一年的诺邓火腿上分离到一株具有纤维素酶活性的嗜盐真菌YFCC2018SY。以形态学结合分子系统学手段对其进行鉴定,用胞外酶活测定法探索其产酶规律,并通过响应面法优化其产酶条件。结果表明该菌株属于球孢枝孢菌,且能分泌滤纸酶、内切酶和β‐葡萄糖苷酶3种嗜盐纤维素酶。响应面分析得到最优发酵条件为:NaCl含量88.58g/L、装瓶量51.21mL、起始pH 7.72。通过优化,纤维素酶活力由113.3U/mL提高到302.8U/mL,提高了167%。上述结果可以为嗜盐纤维素酶开发利用提供参考。