Production Of Amylolytic Enzymes Research Articles

Analyses of challenges faced during the production of amylolytic enzymes and bio-ethanol using left-over cooked-rice, and rice unfit for human consumption

Rice-based enzyme and alcohol production bio-processes using fungi have been explored for years, but they have suffered from the long-pending predicament of presenting their challenges. Currently, major agricultural countries have been resorting to the usage of surplus first-generation biomass sources in bio-refineries. The present lab-scale work proposes, analyzes, and presents the scale-up challenges of such processes while using a novel mixture of left-over cooked rice and market-rejected rice grains. Fractionated rice grains were used as the substrates for enzyme production. Alpha-amylase (365 IU/mL) was produced by employing Aspergillus oryzae 113 ATCC [9102], while glucoamylase (96 IU/mL) was produced by employing Aspergillus niger A1143 NRRL3 [DSM2466] in separate 144-h-long bio-processes. A mixture of left-over cooked rice and rice grains was sequentially saccharified using the produced enzymes, showing a cumulative 51.66% saccharification. Fermentation of the saccharified hydrolysate using Saccharomyces cerevisiae yielded 59.2 g/L bio-ethanol (starch-conversion: 63.3%) with 190-proof purity (95% v/v). The impact of the enzyme/bio-ethanol production on the coefficients of fungal biomass yield (Yx/s, Yx/O2) and maintenance (msx, mO2x), the rates of specific growth (μ) and substrate uptake (SUR) were analyzed individually. A fundamental techno-economic analysis of the entire process has been presented.

Rapid sanitary and technological control of culturing the producers of amylolytic enzymes.

It has been established that the biotechnological process of culturing bacillary microbial producers of amylolytic enzymes can be express-controlled by determining their ATP bioluminescence. The advantages of the method have been shown. The analytical review of producers of hydrolytic enzymes has made it clear how practical it is to use bacillary microorganisms for targeted secretion of amylolytic enzymes in biotechnological production. After monitoring bacillary microorganisms, it has been found advisable to choose Bacillus subtilis ATCC 6633 as the working culture due to its time of production of amylolytic enzymes and its biosynthetic activity. Reasons have been given for using the rapid ATP control method, which is based on the principle of bioluminescence. Different growth media have been compared and evaluated in order to intensify the quantitative biosynthetic activity of the microbial culture in the technological process of culturing bacillary microorganisms. The experiments have proved that growth media can be modified by introducing a number of carbohydrate–protein substrates as inducers of amylolytic complex gene expression. The latter manifests itself in the amylolytic activity accelerated by 12–24 hours, and causes an increase in the number of microorganisms (1.87–3.99 times as many as in the reference culture). Two methods of control (rapid bioluminescent and classic microbiological) have been used for correlative determination of the quantitative growth of Bacillus subtilis cells. Mathematical straight-line correlations have been obtained in a semilogarithmic system for the number of cells of the bacillary producer of the amylolytic enzyme complex. These correlations allow carrying out rapid control in a production environment. Along with the traditional rapid sanitary control in biotechnological production, which includes controlling the contamination of the equipment, personnel’s hands, and water, it has been suggested to perform proprietary technological express control of amylolytic enzyme biosynthesis using the culture Bacillus subtilis ATCC 6633

A cell-factory model of Saccharomyces cerevisiae based on bacterial cellulose without GMO for consolidated bioprocessing of starch

In this study, an effort was made to create a model cell factory of Saccharomyces cerevisiae using bacterial cellulose (BC) and Aspergillus awamori for consolidated bioprocessing (CBP) of starch. This work suggested development of a cell factory for consolidated bioprocessing of starch in one bioreactor, performing three bioprocesses, i.e. production of amylolytic enzymes by fungal culture, hydrolysis of starch and fermentation to ethanol production using S. cerevisiae without its genetic modification. The microorganisms were separately immobilized on different amounts of BC and their mixture was used for the fermentation of 5% w/v starch. The mixture of BC/A. awamori and BC/S. cerevisiae was used for starch fermentation both in wet and freeze-dried (lyophilized) form in the same ratio (3:1). A 1.75-fold increase in maximum ethanol production was observed using freeze-dried BC immobilized biocatalysts compared to wet cell factory. The ethanol production yield was examined progressively by the effect of (i) initial ratios of both freeze-dried BC/S. cerevisiae and BC/A. awamori, (ii) different weight of the freeze-dried cell factory and (iii) A. awamori cells concentration, reaching the 82% of the theoretical yield encouraging us to use this cell factory model for further fermentations of starch in higher concentration. Ethanol production of 26.69 mL/L and the maximum ethanol yield (0.42 g ethanol/g starch) or 82% of the theoretical yield was achieved by increasing cells of A. awamori inoculum during its immobilization on BC to 109 cells/mL. The results of this work are satisfactory compared with other systems of starch fermentation from literature. SEM, TEM and FTIR spectra analysis were carried out in order to prove the successful preparation of cell factory. SEM showed the immobilization of cells on the BC netting, and TEM showed on BC fibrils. Finally, a repeated fermentation batch was performed, proving the operational viability and stability of the cell factory. The results indicated that the objective of designed cell factory was successfully performer, and the results of starch fermentation are promising for the development of an innovation in brewing industry. Likewise, these have prospects of their application in White-Biotechnology.

Artificial AmyR::XlnR transcription factor induces α-amylase production in response to non-edible xylan-containing hemicellulosic biomass

Filamentous fungi belonging to the Aspergillus genus are one of the most favored microorganisms for industrial enzyme production because they can secrete large amounts of proteins into the culture medium. α-Amylase, an enzyme produced by Aspergillus species, is important for food and industrial applications. The production of α-amylase is induced by starch, mainly obtained from the edible biomass; however, the increasing demand for foods is limiting the application of the latter. Therefore, it is expected that using the non-edible biomass, such as rice straw, could improve the competition for industrial application starch containing resources. The transcription factor AmyR activates the transcription of amylolytic enzyme genes, while the transcription factor XlnR activates the transcription of xylanolytic enzyme genes in response to xylose. In this study, we aimed to construct an artificial AmyR::XlnR transcription factor (AXTF) by replacing the DNA-binding domain (1–159 amino acids) of XlnR with that (1–68 aa) of AmyR, which is capable of inducing amylolytic enzyme production in response to xylan-containing hemicellulosic biomass. The chimeric transcription factor AXTF was constructed and expressed using the gapA promoter in the amyR-deficient mutant strain SA1. When the AXTF strain was cultured in the minimal medium containing xylose as the carbon source, the amyB, amyF, agdB, and agdE transcription levels were 41.1-, 11.3-, 37.9-, and 23.7-fold higher, respectively, than those of the wild-type strain. The α-amylase and α-glucosidase activities in the culture supernatant of the AXTF strain grown with xylose for 48 h were 696.6 and 536.1 U/mL, respectively, while these activities were not detected in the culture supernatant of the wild-type and SA1 strains. When rice straw hydrolysate was used as a carbon source, the α-amylase and α-glucosidase activities were 590.2 and 362.7 U/mL, respectively. Thus, we successfully generated an Aspergillus nidulans strain showing amylolytic enzyme production in response to non-edible xylan-containing hemicellulosic biomass by transforming it with the chimeric transcription factor AXTF. Furthermore, the use of genes encoding engineered transcription factors is advantageous because introducing such genes into an industrial Aspergillus strain has similar simultaneous effects on multiple amylase genes controlled by AmyR.

Aspergillus sydowii Strain SCAU066 and Aspergillus versicolor Isolate BAB-6580: Potential Source of Xylanolytic, Cellulolytic and Amylolytic Enzymes

Fungi is known to produce a wide range of biologically active metabolites and enzymes. Enzymes produced by fungi are utilized in food and pharmaceutical industries because of their rich enzymatic profile. Filamentous fungi are particularly interesting due to their high production of extracellular enzymes which has a large industrial potential. The aim of this study is to isolate potential soil fungi species that are able to produce functional enzymes for industries. Five Aspergillus species were successfully isolated from antibiotic overexposed soil (GPS coordinate of N3.093219 E101.40269) by standard microbiological method. The isolated fungi were identified via morphological observations and molecular tools; polymerase chain reactions, ITS 1 (5’- TCC GTA GGT GAA CCT GCG G3’) forward primer and ITS 4 (5’-TCC TCC GCT TAT TGA TAT GC-3’) reverse primer. The isolated fungi were identified as Aspergillus sydowii strain SCAU066, Aspergillus tamarii isolate TN-7, Aspergillus candidus strain KUFA 0062, Aspergillus versicolor isolate BAB-6580, and Aspergillus protuberus strain KAS 6024. Supernatant obtained via submerged fermentation of the isolated fungi in potato dextrose broth (PDB) and extracted via centrifugation was loaded onto specific media to screen for the production of xylanolytic, cellulolytic and amylolytic enzymes. The present findings indicate that Aspergillus sydowii strain SCAU066 and Aspergillus versicolor isolate BAB-6580 have great potential as an alternative source of xylanolytic, cellulolytic and amylolytic enzymes.

Isolation of Filamentous Fungi from the Caatinga Region and Production of Amylolytic Enzymes of Great Industrial Interest

The industrial importance and the high cost of the commercial amylase require the study of microorganisms that produce these enzymes. For this reason, the objective of this work was to isolate filamentous fungi from a region of the caatinga and evaluate their potential for the production of amylase. Four soil samples were collected from a deactivated dump located in the city of Diamantina, MG, in a region of the caatinga. The analysis of amylolytic production in a submerged medium at the ideal temperature of each microorganism was performed using the saccharification method, and the reducing sugars formed were quantified by DNS. Fourteen filamentous fungi were isolated, which had different morphological aspects. Regarding amylase production, a mean activity of 0.477 U·mL-1 was obtained with the isolates I 1.2.1 and I 4.4.1. These results bring important information regarding the biodiversity of the caatinga, in addition to the isolation of microorganisms that can be used as biological machinery to obtain metabolites with high biotechnological and industrial potential.

Amylase from Bacillus sp. Produced by Solid State Fermentation Using Cassava Bagasse as Starch Source.

Abstract Amylases are enzymes involved in starch hydrolysis, generating the most diverse products, such as maltose, glucose and dextrins. This work aimed the study of the production of amylolytic enzymes via solid-state fermentation (SSF) using “crueira”, an essentially starchy cassava residue, as substrate-support and Bacillus sp. as microorganism. For the implementation of the experimental part, a Central Composite Design (CCD) with three variables (initial moisture, pH and temperature) was made. Each test was examined at 24, 48 and 72 hours by the method of starch dextrinizing activity. The optimum production conditions were 60% initial moisture, pH 6 and 37 °C. The maximum yield was 437.76 U/g in 72 hours of fermentation. The optimum temperature of enzyme performance was 65 °C. The pH optimum range was 4 to 6. The Co2 +, Ca2 + and K+ ions positively influenced the activity of enzymes and the Fe2+ ion had no effect on enzymatic activity. On the other hand, the ions Hg2+, Zn2+, Cu2+, Mn2+ and Mg2+ adversely influenced enzymatic activity. Therefore, producing amylases from Bacillus sp. and using crueira as a substrate is possible.

Regulatory mechanisms for amylolytic gene expression in the koji mold Aspergillus oryzae.

The koji mold Aspergillus oryzae has been used in traditional Japanese food and beverage fermentation for over a thousand years. Amylolytic enzymes are important in sake fermentation, wherein production is induced by starch or malto-oligosaccharides. This inducible production requires at least two transcription activators, AmyR and MalR. Among amylolytic enzymes, glucoamylase GlaB is produced exclusively in solid-state culture and plays a critical role in sake fermentation owing to its contribution to glucose generation from starch. A recent study demonstrated that glaB gene expression is regulated by a novel transcription factor, FlbC, in addition to AmyR in solid-state culture. Amylolytic enzyme production is generally repressed by glucose due to carbon catabolite repression (CCR), which is mediated by the transcription factor CreA. Modifying CCR machinery, including CreA, can improve amylolytic enzyme production. This review focuses on the role of transcription factors in regulating A. oryzae amylolytic gene expression.

Identification of an essential regulator controlling the production of raw-starch-digesting glucoamylase in Penicillium oxalicum

BackgroundRaw-starch-digesting glucoamylases (RSDGs) from filamentous fungi have great commercial values in starch processing; however, the regulatory mechanisms associated with their production in filamentous fungi remain unknown. Penicillium oxalicum HP7-1 isolated by our laboratory secretes RSDG with suitable properties but at low production levels. Here, we screened and identified novel regulators of RSDG gene expression in P. oxalicum through transcriptional profiling and genetic analyses.ResultsPenicillium oxalicum HP7-1 transcriptomes in the presence of glucose and starch, respectively, used as the sole carbon source were comparatively analyzed, resulting in screening of 23 candidate genes regulating the expression of RSDG genes. Following deletion of 15 of the candidate genes in the parental P. oxalicum strain ∆PoxKu70, enzymatic assays revealed five mutants exhibiting significant reduction in the production of raw-starch-digesting enzymes (RSDEs). The deleted genes (POX01907, POX03446, POX06509, POX07078, and POX09752), were the first report to regulate RSDE production of P. oxalicum. Further analysis revealed that ∆POX01907 lost the most RSDE production (83.4%), and that POX01907 regulated the expression of major amylase genes, including the RSDG gene POX01356/PoxGA15A, a glucoamylase gene POX02412, and the α-amylase gene POX09352/Amy13A, during the late-stage growth of P. oxalicum.ConclusionOur results revealed a novel essential regulatory gene POX01907 encoding a transcription factor in controlling the production of RSDE, regulating the expression of an important RSDG gene POX01356/PoxGA15A, in P. oxalicum. These results provide insight into the regulatory mechanism of fungal amylolytic enzyme production.

Optimization, kinetic and bioprocess parameters of amylases production from Coprinus comatus under submerged culture using starch-based simple medium: Partial enzyme characterization

Amylases are among of the most important enzymes with industrial application, which can be produced by non-pathogenic saprophytic basidiomycetes, attracting great commercial interest, due to the fact that they are easy to cultivate and present extracellular enzymatic production. Twelve basidiomycete strains were screened for the production of amylolytic enzymes (α-amylase and glucoamylase) were Coprinus comatus, which had highest enzymatic production was chosen to perform the next steps. Next, a Plackett-Burman Screening Design 11/12 was carried out to select the significant variables, among the factors under analysis, three presented significant effect (p < 0.05) for the enzymes: starch, urea and Fe2(SO4)3. The increase in production using Central Composite Rotatable Design (CCRD)resulted in two models represented by the surface of response for both enzymes. In the final kinetics, the maximum activity was obtained after 48 h for α-amylase (5.84 U mL−1; 213 U mg−1) and in 44 h for glucoamylase (8.87 U mL−1; 147.93 U mg−1). The enzymes were characterized for pH, reaction temperature and metallic ions. Optimal pH and temperature for α-amylase were 6.5 and 50 °C, while for glucoamylase they were 6.0 and 50 °C. The presence of Mg2+ ions significantly increased the α-amylase production (43.16%). Glucoamylase, however, had an increase of 168.46% in the presence of Mn2+ ion. The optimization of the C. comatus culture increased the enzymatic production in relation to the production obtained in the selection of α-amylase in 153%, while the increase in glucoamylase was of 2,234%.

Chaperone complex formation of the transcription factor MalR involved in maltose utilization and amylolytic enzyme production in Aspergillus oryzae.

The Zn2Cys6-type transcription factor MalR controls the expression of maltose-utilizing (MAL) cluster genes and the production of amylolytic enzymes in Aspergillus oryzae. In the present study, we demonstrated that MalR formed a complex with Hsp70 and Hsp90 chaperones under non-inducing conditions similar to the yeast counterpart Mal63 and that the complex was released from the chaperone complex after the addition of the inducer maltose. The MalR protein was constitutively localized in the nucleus and mutation in both the putative nuclear localization signals (NLSs) located in the zinc finger motif and the C-terminal region resulted in the loss of nuclear localization. This result indicated the involvement of NSLs in the MalR nuclear localization. However, mutation in both NLSs did not affect the dissociation mode of the MalR-Hsp70/Hsp90 complex, suggesting that MalR activation induced by maltose can occur regardless of its intracellular localization.

Optimization of the production of an extracellular and thermostable amylolytic enzyme by Thermus thermophilus HB8 and basic characterization.

The objective of this study was to determine the potential of Thermus thermophilus HB8 for accumulating a high level of extracellular, thermostable amylolytic enzyme. Initial production tests indicated clearly that only very low levels of amylolytic activity could be detected, solely from cells after extraction using the mild, non-ionic detergent Triton X-100. A sequential optimization strategy, based on statistical designs, was used to enhance greatly the production of extracellular amylolytic activity to achieve industrially attractive enzyme titers. Focus was placed on the optimal level of initial biomass concentration, culture medium composition and temperature for maximizing extracellular amylolytic enzyme accumulation. Empirical models were then developed describing the effects of the experimental parameters and their interactions on extracellular amylolytic enzyme production. Following such efforts, extracellular amylolytic enzyme accumulation was increased more than 70-fold, with enzyme titers in the 76U/mL range. The crude extracellular enzyme was thereafter partially characterized. The optimal temperature and pH values were found to be 80°C and 9.0, respectively. 100% of the initial enzyme activity could be recovered after incubation for 24h at 80°C, therefore, proving the very high thermostability of the enzyme preparation.

CAMBIOS FISICOQUÍMICOS DE ALMIDÓN DE MAÍZ DURANTE LA FERMENTACIÓN ACIDO LÁCTICA CON Lactobacillus bulgaricus

Lactic acid fermentation with L. bulgaricus induced large changes in the morphology of corn starch granules. The production of amylolytic enzymes as well as lactic acid produced fractures along the granule hilum, which led to disintegration of starch granules at long fermentation times. On the other hand, lactic acid fermentation increased crystallinity and double-helices structures, which led to increased susceptibility to acidic hydrolysis. In fact, thermal analysis results indicated than an improved internal organization of granule residues occurred. In general, the results showed that the fermentation time can be considered as a suitable parameter for modulating the physicochemical properties of corn starch granules. Additionally, it can be postulated that lactic acid fermentation of starchy food matrices has a positive effect on the acidic digestibility of starch granules, by improving the content of resistant starch fractions

Production and purification of amylolytic enzymes for saccharification of microalgal biomass

The aim of this study was the production of amylolytic enzymes by solid state or submerged fermentations (SSF or SF, respectively), followed by purification using chemical process or microfiltration and immobilization of purified enzymes in a polyurethane support. The free and immobilized enzymes obtained were used to evaluate enzymatic hydrolysis of the polysaccharides of Spirulina. Microfiltration of the crude extracts resulted in an increase in their specific activity and thermal stability at 40°C and 50°C for 24h, as compared to extracts obtained by SSF and SF. Immobilization of polyurethane purified enzyme produced yields of 332% and 205% for the enzymes obtained by SF and SSF, respectively. Free or immobilized enzymes favor the generation of fermentable sugar, being the application of the purified and immobilized enzymes in the hydrolysis of microalgal polysaccharides considered a promising alternative towards development of the bioethanol production process from microalgal biomass.

Endocytosis of a maltose permease is induced when amylolytic enzyme production is repressed in Aspergillus oryzae

In the filamentous fungus Aspergillus oryzae, amylolytic enzyme production is induced by the presence of maltose. Previously, we identified a putative maltose permease (MalP) gene in the maltose-utilizing cluster of A. oryzae. malP disruption causes a significant decrease in α-amylase activity and maltose consumption, indicating that MalP is a maltose transporter required for amylolytic enzyme production in A. oryzae. Although the expression of amylase genes and malP is repressed by the presence of glucose, the effect of glucose on the abundance of functional MalP is unknown. In this study, we examined the effect of glucose and other carbon sources on the subcellular localization of green fluorescence protein (GFP)-tagged MalP. After glucose addition, GFP–MalP at the plasma membrane was internalized and delivered to the vacuole. This glucose-induced internalization of GFP–MalP was inhibited by treatment with latrunculin B, an inhibitor of actin polymerization. Furthermore, GFP–MalP internalization was inhibited by repressing the HECT ubiquitin ligase HulA (ortholog of yeast Rsp5). These results suggest that MalP is transported to the vacuole by endocytosis in the presence of glucose. Besides glucose, mannose and 2-deoxyglucose also induced the endocytosis of GFP–MalP and amylolytic enzyme production was inhibited by the addition of these sugars. However, neither the subcellular localization of GFP–MalP nor amylolytic enzyme production was influenced by the addition of xylose or 3-O-methylglucose. These results imply that MalP endocytosis is induced when amylolytic enzyme production is repressed.

Bacillus sp. R2 and Bacillus Cereus Immobilized Amylases for Glucose Syrup Production

The availability of starch from inexpensive sources such as agro-wastes and agricultural byproducts, added to a large-scale production of amylolytic enzymes, facilitates the production of syrups containing glucose, fructose or maltose, which are of considerable importance in the pharmaceutical and food industries. This study aimed to produce a glucose syrup from an agricultural by-product i.e. wheat bran; using amylase immobilization in calcium alginate beads. To improve the amylase production of the two used strains Bacillus sp . R2 and Bacillus cereus , a continuous immobilization in 2% calcium alginate beads was conducted. The best amylase activity (421,73U/ml) was obtained after 20 h with Bacillus cereus . The hydrolysis product analyzed by thin layer chromatography TLC was predominantly identified as glucose and xylose. The obtained results showed a great potential of the two Bacillus species to produce amylases, also the entrapped enzymes gave significantly higher hydrolysis activity compared to free amylases.

Distinct mechanism of activation of two transcription factors, AmyR and MalR, involved in amylolytic enzyme production in Aspergillus oryzae.

The production of amylolytic enzymes in Aspergillus oryzae is induced in the presence of starch or maltose, and two Zn2Cys6-type transcription factors, AmyR and MalR, are involved in this regulation. AmyR directly regulates the expression of amylase genes, and MalR controls the expression of maltose-utilizing (MAL) cluster genes. Deletion of malR gene resulted in poor growth on starch medium and reduction in α-amylase production level. To elucidate the activation mechanisms of these two transcription factors in amylase production, the expression profiles of amylases and MAL cluster genes under carbon catabolite derepression condition and subcellular localization of these transcription factors fused with a green fluorescent protein (GFP) were examined. Glucose, maltose, and isomaltose induced the expression of amylase genes, and GFP-AmyR was translocated from the cytoplasm to nucleus after the addition of these sugars. Rapid induction of amylase gene expression and nuclear localization of GFP-AmyR by isomaltose suggested that this sugar was the strongest inducer for AmyR activation. In contrast, GFP-MalR was constitutively localized in the nucleus and the expression of MAL cluster genes was induced by maltose, but not by glucose or isomaltose. In the presence of maltose, the expression of amylase genes was preceded by MAL cluster gene expression. Furthermore, deletion of the malR gene resulted in a significant decrease in the α-amylase activity induced by maltose, but had apparently no effect on the expression of α-amylase genes in the presence of isomaltose. These results suggested that activation of AmyR and MalR is regulated in a different manner, and the preceding activation of MalR is essential for the utilization of maltose as an inducer for AmyR activation.

Detection of Thermostable Amylases Produced by Thermophilic Fungi Isolated from some Ethiopian Hyper-Thermal Springs

One thousand five hundred and nine thermophilic strains of water and soil fungi from six hyperthermal springs of Ethiopia ( Arbaminch , Awassa , Nazret , Shalla /Abijata , Wendo Genet and Yirgalem) were isolated on Potato Dextrose Agar at 45 o C for 3 to 5 days. Amylase active fungi were detected by growing the purified organisms on starch agar plates and flooding by Gram’s iodine solution. During their metabolism 61 strains (about 4.04%) formed a clear halo around the colony while flooded with Gram’s iodine solution indicating starch degradation. While nearly 37.5% of the crude alpha amylase extracts obtained from the strains isolated from Shalla/Abijata showed activity at 60 o C only about 8% of those obtained from Arbaminch effectively hydrolyzed starch at this temperature. Further purification and characterization studies of enzyme will lead to a better knowledge of promising candidates of thermophilic microorganisms and processing conditions for enhanced production of thermostable amylolytic enzymes.

Production of α-amylase from Streptomyces sp. SLBA-08 strain using agro-industrial by-products

Approximately 1.5 trillion tons are the estimated yearly biomass production, making it an essentially unlimited source of raw material for environmentally friendly and biocompatible products transformed by microorganism, specially fungi and actinomycetes. Several lignocellulosic residues, such as sisal waste and sugarcane bagasse contain starch in their structures which could become important sources for the production of amylases. This study evaluated the production of amylolytic enzymes using Streptomyces sp. SLBA-08 strain, isolated from a semi-arid soil, according to their ability to grow on soluble starch as the sole carbon source. The effect of the carbon source (sisal waste and sugarcane bagasse) on α-amylase production was studied using submerged cultivations at 30 oC. The highest level of α-amylase activity corresponded to 10.1 U. mL-1 and was obtained using sisal waste (2.7%) and urea (0.8%) in submerged fermentation after 3 days of cultivation. The partial characterization showed the best α-amylase activity at 50oC and pH 7.0. These results are of great importance for the use of sisal waste as a substrate for biotechnological proposes.

Indigestible dextrin is an excellent inducer for α-amylase, α-glucosidase and glucoamylase production in a submerged culture of Aspergillus oryzae

α-Amylase activities of Aspergillus oryzae grown on dextrin or indigestible dextrin were 7·8 and 27·7Uml(-1), respectively. Glucoamylase activities of the cultures grown on dextrin or indigestible dextrin were 5·4 and 301mUml(-1), respectively. The specific glucoamylase production rate in indigestible dextrin batch culture reached 1·35UgDW(-1)h(-1). In contrast, biomass concentration of A. oryzae in indigestible dextrin culture was 35% of that in dextrin culture. Thus, the culture method using indigestible dextrin has the potential to improve amylolytic enzyme production and fungal fermentation broth rheology.