Production of pectinesterase and polygalacturonase by Aspergillus niger in submerged and solid state systems

Production of pectinesterase and polygalacturonase by Aspergillus niger was studied in submerged and solid-state fermentation systems. With pectin as a sole carbon source, pectinesterase and polygalacturonase production were four and six times higher respectively in a solid state system than in a submerged fermentation system and required a shorter time for enzyme production. The addition of glucose increased pectinesterase and polygalacturonase production in the solid state system but in submerged fermentation the production was markedly inhibited. A comparison of enzyme productivities showed that those determined for pectinesterase and polygalacturonase with pectin as a carbon source were three and five times higher by using the solid state rather than the submerged fermentation system. The productivities of the two enzymes were affected by glucose in both fermentation systems. The membranes of cells from the solid state fermentation showed increased levels of C18:1, C16:0 and C18:0 fatty acids. Differences in the regulation of enzyme synthesis by Aspergillus niger depended on the fermentation system, favoring the solid state over the submerged fermentation for pectinase production. Received 12 May 1997/ Accepted in revised form 19 September 1997     

Absorbed substrate fermentation for pectinase production with Aspergillus niger

Summary A 130 litre packed-bed bioreactor was used for pectinase production with Aspergillus niger using absorbed substrate fermentation techniques. Pectinolytic enzyme activity and relative CO₂ production were used as indicators of metabolic activity. Absorbed substrate fermentation is an efficient process for pectinase production and is also an interesting model because the culture medium, water, nutrients and specific inducers, can be designed at the desired concentrations.     

Production of pectinases byAspergillus sp using differently pretreated lemon peel as the carbon source

Summary Aspergillus sp strains from decaying lemons were tested for extracellular pectinase production, testing differently pretreated lemon peel as the carbon source instead of pectin. It was found that the production of extracellular polygalacturonase was about the same and that of pectinesterase substantially higher when unwashed fresh lemon peel was used instead of pectin. The culture filtrate obtained showed a clarifying capacity similar to that of a commercial pectinase preparation, but the vitamin C of the juice was less affected by the treatment.     

Synthesis of itaconic acid from agricultural waste using novel Aspergillus niveus

Abstract

Filamentous fungi from the genus Aspergillus are of high importance for the production of organic acids. Itaconic acid (IA) is considered as an important component for the production of synthetic fibers, resin, plastics, rubber, paints, coatings, adhesives, thickeners and binders. Aspergillus niveus MG183809 was isolated from the soil sample (wastewater unit) which was collected from Avadi, Chennai, India. In the present study, itaconic acid was successfully produced by isolated A. niveus by submerged batch fermentation. In the fermentation process, various low-cost substrates like corn starch, wheat flour and sweet potato were used for itaconic acid production. Further, the factor influencing parameters such as substrate concentration and incubation period were optimized. Maximum yield of itaconic acid (15.65?±?1.75?g/L) was achieved by using A. niveus from corn starch at a concentration of 120?g/L after 168?hr (pH 3.0). And also extraction of itaconic acid from the fermentation was performed with 91.96?±?1.57 degree of extraction.     

Solid‐state fermentation for the production of debittering enzyme naringinase using Aspergillus niger MTCC 1344

Aspergillus niger produced high levels of naringinase using easily available, inexpensive industrial waste residues such as rice bran, wheat bran, sugar cane bagasse, citrus peel, and press mud in solid‐state fermentation (SSF). Among these, rice bran was found to be the best substrate. Naringinase production was highest after 96 h of incubation at 27°C and at a substrate‐to‐moisture ratio of 1:1 w/v. Supplementation of the medium with 10% naringin caused maximum induction. An inoculum age of 72 h and an inoculum level of 15% resulted in maximum production of naringinase. Enzyme production was stimulated by the addition of nutrients such as naringin and peptone. Thus, A. niger produced a very high level of naringinase within a short time in solid‐state fermentation using inexpensive agro‐residues, a level that is much higher than reported for any other microbes.     

Production of kojic acid by Aspergillus species: Trends and applications

Kojic acid (KA), produced mainly by Aspergillus species, is a product of fungal secondary metabolism and has great potential in biotechnological applications. The use of KA has steadily increased, chiefly in the pharmaceutical industry, where KA is used for skin lightning. The market for KA has grown considerably in recent years and is expected to reach $39 million by 2026. In this review, we summarise the relevant information regarding the application of KA, describe the optimal cultivation conditions for Aspergillus species used in the production of KA, and assess the prospects for the KA market. Based on our findings, we established that the highest yields of KA can be achieved using submerged fermentation with glucose and yeast extract as the primary sources of carbon and nitrogen, respectively. Furthermore, according to literature, the main species/strains reported as the best producers of KA are Aspergillus flavus (44-L), Aspergillus oryzae (AR-47 and NRRL 484), and Aspergillus terreus (C5-10 mutant of the strain PTCC 5283). Given the commercial importance of KA and the growing demand for this natural product, further studies are needed to identify novel strains of Aspergillus as potential high producers of this acid. Similarly, it will be desirable to identify novel sources of substrate for the low-cost production of KA, thereby promoting its production for use in pharmaceutical, healthcare, and other potential industrial applications. In addition, given the current limited knowledge regarding the biosynthetic pathway of KA, further studies are required to elucidate that biosynthetic pathway.     

Utilization of agro-industrial orange peel and sugar beet pulp wastes for fungal endo- polygalacturonase production

The pectinase enzymes are involved in several industrial applications, and industrial waste is one of the largest environmental pollutants, so this study aims to Endo-polygalacturonase (endo-PG) producing using Aspergillus niger AUMC 4156, Penicillium oxalicum AUMC 4153 and P. variotii AUMC 4149 by using some agro-industrial wastes (dried orange peel and sugar beet pulp) as a sole raw carbon source for degradation these waste in the process of urban wastes disposal. The fermentation process was carried out as a submerged culture technique under both shaken and static culture conditions. A. niger AUMC 4156 was the most promising producer of endo-PG under static conditions while P. oxalicum AUMC 4153 was the highest producer of endo-PG under shaken conditions. Sugar beet pulp proved to be the most preferable to orange peel as the only source of carbon in both shaken and static cultures. The medium that encompassing orange peel as a single carbon source afforded the highest protein content with all tested fungal strains in stirred and static cultures in comparison with sugar beet pulp. The highest activity of endo-polygalacuronase that produced using A. niger AUMC 4156 and P. oxalicum AUMC 4153 was achieved by using sugar beet pulp at 3% concentration under static cultures, meanwhile maximal enzyme activity produced by both fungal strains required 2% sugar beet pulp under shaken cultures. Sugar beet pulp showed promised potential as a good inducer for endo-polygalacturoase production, and enzymes production depended on fungal strains, culture medium, and submerged fermentation conditions.     

Biosynthesis of D-mannitol from D-glucose by Aspergillus candidus

Mannitol has long been known as a product of glucose metabolism by some strains of Aspergillus. Apparently no concerted effort, has been made to develop a practical fermentation process to make mannitol. Work at the Northern Laboratory has shown that nearly all strains of white Aspergillus produce significant amounts of mannitol; many strains of black Aspergillus also have this characteristic. Aspergillus candidus NRRL 305 is an exceptionally good mannitol producer. Studies on a fermentation process were conducted in 20-1, stainless steel fermentors, without baffles. Czapek-Dox medium, modified by addition of corn meal, yeast extract, and enzymatically hydrolyzed casein was the most satisfactory medium tested. Suitable increments of glucose were fed daily to the fermentors. The duration of the fermentation was from 10 to 16 days. The effects of agitation, aeration, temperature, and pH of the medium were studied. Under optimal conditions yields of mannitol approached 50% of the glucose consumed.     

Effective technological pectinases by Aspergillus carneus NRC1 utilizing the Egyptian orange juice industry scraps

The production of a notable and highly effective pectinase by the local fungal strain Aspergillus carneus NRC1 utilizing the abundant Egyptian orange peels and pulps (OPP) scraps excluded in the orange juice and canning industry was achieved in 5-day submerged fermentation (SMF) cultures, at temperature and pH ranges of 30–55 °C and 5.0–5.5, respectively. Fresh or thawed OPP (6%, w/v) were the most preferable sole carbon source. Pectinase activity was dramatically stimulated by ammonium sulphate as the sole nitrogen source, and at the same time strongly inhibited the production of the other tested enzymes, i.e., cellulases and hemicellulases. The lyophilized enzyme preparation was free from any ochra or aflatoxins. The optimum conditions of this methodology including enzyme and substrate (citrus pectin) concentrations were 40 mg ml^?1 and 7% (w/v), respectively, with pH and temperature of 4.0 and 55 °C, respectively.     

Effects of different carbon sources on the synthesis of pectinase by Aspergillus niger in submerged and solid state fermentations

A study was made to compare the production of pectinase by Aspergillus niger CH4 in solid-state (SSF) and submerged (SmF) fermentations. Production of endo- (endo-p) and exo-pectinase (exo-p) by SSF was not reduced when glucose, sucrose or galacturonic acid (up to 10%) were added to a culture medium containing pectin. Moreover, both activities increased when concentrations of the carbon sources were also increased. In SmF, these activities were strongly decreased when glucose or sucrose (3%) was added to culture medium containing pectin. The addition of galacturonic acid affected endo-p activity production to a lesser extend than exo-p. Final endo-p and exo-p activities in SSF were three and 11 times higher, respectively, than those obtained in SmF. The overall productivities of SSF were 18.8 and 4.9 times higher for endo-p and exo-p, respectively, than those in SmF. These results indicate that regulatory phenomena, such as induction-repression or activation-inhibition, related to pectinase synthesis by A. niger CH4 are different in the two types of fermentation. Correspondence to: E. Favela-Torres     

Cost-effective and concurrent production of industrially valuable xylano-pectinolytic enzymes by a bacterial isolate Bacillus pumilus AJK

Simultaneous production of xylanase and pectinase by Bacillus pumilus AJK under submerged fermentation was investigated in this study. Under optimized conditions, it produced 315?±?16 IU/mL acidic xylanase, 290?±?20 IU/mL alkaline xylanase, and 88?±?9 IU/mL pectinase. The production of xylano-pectinolytic enzymes was the highest after inoculating media (containing 2% each of wheat bran and Citrus limetta peel, 0.5% peptone, 10?mM MgSO₄, pH 7.0) with 2% of 21-hr-old culture and incubated at 37°C for 60?hr at 200?rpm. Xylanase retained 100% activity from pH 6.0 to10.0 after 3?hr of incubation, while pectinase showed 100% stability from pH 6.0 to 9.0 even after 6?hr of incubation. Cost-effective and concurrent production of xylanase and pectinase by a bacterial isolate in the same production media suggests its potential for various biotechnological applications. This is the first report of simultaneous production of industrially important extracellular xylano-pectinolytic enzymes by B. pumilus.     

New application of Aspergillus versicolor in promoting plant growth after suppressing sterigmatocystin production via genome mining and engineering

Aspergillus genus is a key component in fermentation and food processing. However, sterigmatocystin (STE)—a mycotoxin produced by several species of Aspergillus—limits the use of some Aspergillus species (such as Aspergillus versicolor, Aspergillus inflatus, and Aspergillus parasiticus) because of its toxicity and carcinogenicity. Here, we engineered an STE-free Aspergillus versicolor strain based on genome mining techniques. We sequenced and assembled the Aspergillus versicolor D5 genome (34.52 Mb), in which we identified 16 scaffolds and 54 biosynthetic gene clusters (BGCs). We silenced cytochrome P450 coding genes STC17 and STC27 by insertional inactivation. The production of STE in the Δstc17 mutant strain was increased by 282% but no STE was detected in the Δstc27 mutant. Metabolites of Δstc27 mutant exhibited growth-promoting effect on plants. Our study makes significant progress in improving the application of some Aspergillus strains by restricting their production of toxic and carcinogenic compounds.     

Production of thermostable pectinase and xylanase for their potential application in bleaching of kraft pulp

A very high level of alkalophilic and thermostable pectinase and xylanase has been produced from newly isolated strains of Bacillus subtilis and Bacillus pumilus respectively. Enzyme production for pectinase was carried out under SSF using combinations of cheap agricultural residues while xylanase was produced under submerged fermentation using wheat bran as substrate to minimize the cost of production of these enzymes Among the various substrates tested, the highest yield of pectinase production was observed by using combination of WB + CW (6592 U/g of dry substrate) supplemented with 4% yeast extract when incubated at 37 °C for 72 h using deionized water of pH 7.0 as moistening agent. The biobleaching effect of these cellulase free enzymes on kraft pulp was determined. Both xylanase and pectinase showed stability over a broad range of pH from 6 to 10 and temperature from 55 to 70 °C. The bleaching efficiency of the pectinase and xylanase on kraft pulp was maximum after 150 min at 60 °C using enzyme dosage of 5 IU/ml of each enzyme at 10% pulp consistency with about 16% reduction in kappa number and 84% reduction in permanganate number. Enzyme treated pulp when subjected to CDED₁D₂ steps, 25% reduction in chlorine consumption and upto 19% reduction in consumption of chlorine dioxide was observed for obtaining the same %ISO brightness. Also an increase of 22 and 84% in whiteness and fluorescence respectively and a decrease of approximately 19% in the yellowness of the biotreated pulp were observed by pretreatment of the pulp with our enzymatic mixture.     

Pectinase production by a Brazilian thermophilic fungus <Emphasis Type="Italic">Thermomucor indicae-seudaticae</Emphasis> N31 in solid-state and submerged fermentation

Thermophilic organisms produce thermostable enzymes, which have a number of applications, justifying the interest in the isolation of new thermophilic strains and study of their enzymes. Thirty-four thermophilic and thermotolerant fungal strains were isolated from soil, organic compost, and an industrial waste pile based on their ability to grow at 45°C and in a liquid medium containing pectin as the only carbon source. Among these fungi, 50% were identified at the genus level as Thermomyces, Aspergillus, Monascus, Chaetomium, Neosartoria, Scopulariopsis, and Thermomucor. All isolated strains produced pectinase during solid-state fermentation (SSF). The highest polygalacturonase (PG) activity was obtained in the culture medium of thermophilic strain N31 identified as Thermomucor indicae-seudaticae. Under SSF conditions on media containing a mixture of wheat bran and orange bagasse (1 : 1) at 70% of initial moisture, this fungus produced the maximum of 120 U/ml of exo-PG, while in submerged fermentation (SmF) it produced 13.6 U/ml. The crude PG from SmF was more thermostable than that from SSF and exhibited higher stability in acidic pH.     

Production and properties of three pectinolytic activities produced byAspergillus niger in submerged and solid-state fermentation

Three extracellular pectinases were produced byAspergillus niger CH4 by submerged and solid-state fermentation, and their physicochemical and kinetic properties were studied. The highest productivities of endo- and exo-pectinase and pectin lyase were obtained with solid-state fermentation. The kinetic and physicochemical properties of these enzymes were influenced by the type of culture method used. All activities were very different in terms of pH and temperature optima, stability at different pH and temperature values and affinity for the substrate (K _m values). In solid-state fermentation, all pectinase activities were more stable at extreme pH and temperature values but theK _m values of endo-pectinase and pectin lyase were higher with respect to those activities obtained by the submerged-culture technique. The pectin lyase activity obtained by the submerged-culture technique showed substrate inhibition but the enzyme obtained by solid-state fermentation did not. Electrophoresis, using sodium dodecyl sulphate/polyacrylamide gel with enzymatic extracts obtained for both culture methods, showed the same number on protein bands but some differences were found in their electrophoretic position. The results obtained in this work suggest that the culture method (submerged or solid-state) may be responsible for inducing changes in some of the pectinolytic enzymes produced byA. niger.     

柚子皮黑曲霉的分离鉴定及产酶特性研究

对柚子皮上自然生长的黑曲霉进行分离鉴定,并探讨其产酶特性。以平板稀释法从柚子皮上分离出一株霉菌菌株,通过观察其形态特征和培养特征,对照《真菌鉴定手册》判定该菌株的种属;采用鉴定培养基法对其产酶特性进行分析。根据柚子皮的成分特性,以干柚子皮为主要原料,该菌为生产菌株,采用固态发酵法探究培养基的成分、柚子皮含量、培养基初始含水量及发酵时间4个因素对纤维素酶活力的影响。结果表明,该菌株为黑曲霉(Aspergillus nige),可产淀粉酶、蛋白酶、纤维素酶、果胶酶;固态发酵培养基中添加柚子皮12g,麸皮0.5 g和(NH_4)_2SO_40.5 g,培养基初始含水量保持在68.5 mL/100 g,培养时间控制在60 h左右时纤维素酶产量较高。     

Biotechnological conversion of waste cooking olive oil into lipid-rich biomass using Aspergillus and Penicillium strains

Aims: In this study, we have investigated the biochemical behaviour of Aspergillus sp. (five strains) and Penicillium expansum (one strain) fungi cultivated on waste cooking olive oil. The production of lipid‐rich biomass was the main target of the work. In parallel, the biosynthesis of other extracellular metabolites (organic acids) and enzyme (lipase) and the substrate fatty acid specificity of the strains were studied. Methods and Results: Carbon‐limited cultures were performed on waste oil, added in the growth medium at 15 g l^?1, and high biomass quantities were produced (up to c. 18 g l^?1, conversion yield of c. 1·0 g of dry biomass formed per g of fat consumed or higher). Cellular lipids were accumulated in notable quantities in almost all cultures. Aspergillus sp. ATHUM 3482 accumulated lipid up to 64·0% (w/w) in dry fungal mass. In parallel, extracellular lipase activity was quantified, and it was revealed to be strain and fermentation time dependent, with a maximum quantity of 645 U ml^?1 being obtained by Aspergillus niger NRRL 363. Storage lipid content significantly decreased at the stationary growth phase. Some differences in the fatty acid composition of both cellular and residual lipids when compared with the initial substrate fat used were observed; in various cases, cellular lipids more saturated and enriched with arachidic acid were produced. Aspergillus strains produced oxalic acid up to 5·0 g l^?1. Conclusions: Aspergillus and Penicillium strains are able to convert waste cooking olive oil into high‐added‐value products. Significance and Impact of the Study: Increasing fatty wastes amounts are annually produced. The current study provided an alternative way of biovalourization of these materials, by using them as substrates, to produce added‐value compounds.     

Optimization of enzymatic hydrolysis and fermentation conditions for improved bioethanol production from potato peel residues

The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 g L^?1 of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30 g L^?1 after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:397–406, 2017     

Production of macerating enzymes of mandarin orange peel by fungal cultures

Summary Thirty-nine fungal cultures belonging to the genera of Aspergillus, Podospora, Sordaria, Cbaetomium, Iodophanus, Scleotinia, Coniella, Pellicularia and others, were examined for the production of enzymes which macerate the mandarin orange peel using a wheat bran as substrate. An isolated strain of Aspergillus niger was an excellent producer of macerating enzymes compared to other organisms tested. The peel of the mandarin orange could be macerated by the crude enzymes produced by isolated A. niger. The maceration of 1 g of peel/24 h yielded 0.57 g of reducing sugars. Expressed differently, 83% of solid peel materials were released from the peel into the water/24 h under the following conditions: a peel concentration of 8 g peel/l, a crude enzyme concentration of 1 g protein/l, a temperature of 40°C, a pH of 5, a 24 h incubation time and 120 rpm reciprocal shaking. The test of the macerating activity of commercially available hydrolases on the orange peel showed that the two samples of pectinase originating from A. niger had about the same activity as isolated A. niger whereas the two samples of cellulase originating from Trichoderma viride had remarkably lower activities than A. niger.