Optimization of a biological process for treating potato chips industry wastewater using a mixed culture of Aspergillus foetidus and Aspergillus niger

Potato chips industry wastewater was collected and analyzed for biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and total carbohydrates. Two Aspergillus species, A. foetidus and A. niger, were evaluated for their ability to grow and produce biomass and reduce the organic load of the wastewater. A. foetidus MTCC 508 and A. niger ITCC 2012 were able to reduce COD by about 60% and produce biomass 2.4 and 2.85 gl(-1), respectively. Co-inoculation of both Aspergillus strains resulted in increased fungal biomass production and higher COD reduction than in individual culture at different culture pH. pH 6 was optimum for biomass production and COD reduction. Amendment of the wastewater with different N and P sources, increased the biomass production and COD reduction substantially. Under standardized conditions of pH 6 and amendment of wastewater with 0.1% KH2PO4 and 0.1% (NH4)2 SO4, a mixed culture gave 90% reduction in COD within 60 h of incubation.     

Screening of some wild fungal isolates for cellulolytic activities

Six wild fungal strains, Trichoderma viride, T. harzianum, Gliocladium virens, Aspergillus terreus, A. niger and Tiarosporella phaseolina , isolated from decomposed jute stacks and diseased jute stem, were tested for their cellulolytic and hemicellulolytic activities and compared with T. reesei MCG 77. Filter paper cellulase production by all these wild strains were lower than those produced by T. reesei while some strains ( T. viride, T. harzianum and G. virens ) possessed carboxymethyl cellulase, β-glucosidase, xylanase and β-xylosidase activities comparable to T. reesei. A. terreus and A. niger produced 3·2 and 1·2 times respectively, greater β-glucosidase activity compared to T. reesei when grown on microcrystalline cellulose.     

Evaluation of azo dyes degradation potential of fungal strains and their role in wastewater treatment

In the present investigation, two fungal strains were exploited to evaluate their degradation capability on Synozol Red, Yellow, and Navy-Blue dyes which gave the utmost decolorization such as 40%, 70%, 90% by Aspergillus niger, and 36%, 73%, 87% by Trichoderma viride, respectively for 60 days. The Gas Chromatography-Mass Spectrometry (GC–MS) analysis of the decolorized dyes suggested that various compounds such as Caprolactam, Furazan-3-carboxamide, oxime, 4-amino-N, N-dimethyl, 6H-Pyrazolo[1,2-a] [1,2,4,5]tetrazine, Hexahydro-2,3-dimethyl, Benzene, 1-propenyl, Dihydroxymaleic acid, Arsenous acid, tris(trimethylsilyl) ester were produced by the fungi which helped in the removal of dyes from the wastewater. The laccase activity of the degraded dyes was proof that both of the strains positively produced the enzyme that helped in the biodegradation of carcinogenic dyes into less harmful products. The A. niger extracted laccase relative activity was 262%, 265%, and 145.7% for Synozol Yellow, Synozol Red, and Navy Blue, respectively. Similarly, laccase, obtained from T. viride, showed relative activity of 187.5% against Synozol Yellow, 215% against Synozol Red, and 202% against Navy Blue. Furthermore, the supernatant extracted from fungi-decolorized wastewater was used to check phytotoxicity on Vigna radiata, which gave excellent results. Both fungal strains, on the basis of their dye degradation potential, can be used to ameliorate wastewater contaminated with azo dyes.     

Biotechnological production of lactic acid integrated with fishmeal wastewater treatment by <Emphasis Type="Italic">Rhizopus oryzae</Emphasis>

Fishmeal wastewater, a seafood processing waste, was utilized for production of lactic acid and fungal biomass by Rhizopus oryzae AS 3.254 with the addition of sugars. The 30 g/l exogenous glucose in fishmeal wastewater was superior to starch in view of productivities of lactic acid and fungal biomass, and COD reduction. Fishmeal wastewater can be a replacement for peptone which was the most suitable nitrogen source for lactic acid production among the tested organic or inorganic nitrogen sources. Exogenous NaCl (12 g/l) completely inhibited the production of lactic acid and fungal growth. In the medium of COD 5,000 mg/l fishmeal wastewater with the addition of 30 g/l glucose, the maximum productivity of lactic acid was 0.723 g/l h corresponding to productivity of fungal biomass 0.0925 g/l h, COD reduction 84.9% and total nitrogen removal 50.3% at a fermentation time of 30 h.     

优化黑曲霉菌丝球形成条件提高豆制品废水处理效率

豆制品废水的处理是豆制品厂的一个重要环节。利用黑曲霉在培养过程中形成的菌丝球处理豆制品废水具有安全性好、菌体回收简单、成本低等优点。本实验中以察氏培养基为基础研究了黑曲霉菌丝球的形成条件,并评价了对豆制品废水的处理效果。结果表明在黑曲霉孢子浓度为7.23×10~3/L~8.68×10~6/L、初始pH 3.5~pH 7.5、葡萄糖浓度为0 g/L~30 g/L的条件下都可以形成茵丝球。在豆制品废水中黑曲霉孢子浓度为1.45×10~4/L~7.23×10~5/L、pH 3.7~pH 6.6均可以形成茵丝球,而且在初始pH 5.6时经过72 h的培养豆制品废水变得澄清,COD下降了56.34%。本研究表明利用黑曲霉在豆制品废水中形成菌丝球的方式是一种有潜力的处理方式。     

白腐菌对木质素降解能力的测定

本文测定了7种霉菌对木质素的降解作用。结果表明,在测试的7种霉菌中,米曲霉(Aspergillus oryzal)2013、米曲霉2014、米曲霉2015和黑曲霉(Aspergillus niger)对木质素的降解能力较强,其降解率均达到90%以上。野外分离得到的细菌对木质素没有降解作用。     

Expression of Aspergillus hemoglobin domain activities in Aspergillus oryzae grown on solid substrates improves growth rate and enzyme production

DNA fragments coding for hemoglobin domains (HBD) were isolated from Aspergillus oryzae and Aspergillus niger. The HBD activities were expressed in A. oryzae by introduction of HBD gene fragments under the control of the promoter of the constitutively expressed gpdA gene. In the transformants, oxygen uptake was significantly higher, and during growth on solid substrates the developed biomass was at least 1.3 times higher than that of the untransformed wild-type strain. Growth rate of the HBD-activity-producing strains was also significantly higher compared to the wild type. During growth on solid cereal substrates, the amylase and protease activities in the extracts of the HBD-activity-producing strains were 30-150% higher and glucoamylase activities were at least 9 times higher compared to the wild-type strain. These results suggest that the Aspergillus HBD-encoding gene can be used in a self-cloning strategy to improve biomass yield and protein production of Aspergillus species.     

SCP and crude pectinase production by slurry-state fermentation of lemon pulps

Single cell protein (SCP) and crude pectinolytic enzymes production from citrus pulps is reported. SCP and enzymes were produced by slurry-state flask cultivation of Aspergillus niger and Trichoderma viride on pulps from lemon juice clarification. Production as well as crude pectinase activity was not affected by the high dry matter content of the pulps. Both the protein content in the residue and the enzyme activity in the supernatant were higher in T. viride than in A. niger culture. The crude pectinase of T. viride, whose specific activity was similar to that found for a commercial concentrated preparation, could be utilized in the same citrus processing factory as well as in other factories which use large amounts of pectinolytic crude preparations, for example to enhance depuration plant performance.     

Influence of fungal elicitors on production of ajmalicine by cell cultures of Catharanthus roseus

Suspension cultures of Catharanthus roseus (C. roseus) were elicited with fungal cell wall fragments of Aspergillus niger (A. niger), Fusarium moniliforme (F. moniliforme), and Trichoderma viride (T. viride). The effects of elicitor dosage, exposures time, and age of subculture on ajmalicine accumulation were studied. A higher concentration of elicitor extract responded positively to C. roseus suspension cultures. Ajmalicine accumulation increased by about 3-fold when cells were treated with A. niger, F.moniliforme, and T. viride. The maximum ajmalicine production (75 microg g(-1) dry weight (DW)) was observed in cells treated with T. viride. Cell cultures were elicited with 5% preparation of A. niger, F. moniliforme, and T. viride and exposed for 24, 48, 72, and 96 h. for elicitation. Suspension cultures elicited with T. viride for 48 h showed a 3-fold increase (87 microg g(-1) DW) in ajmalicine contents, whereas A. niger and F. moniliforme synthesized a 2-fold increase in alkaloid and yielded 52 and 56 microg g(-1) DW ajmalicine, respectively. C. roseus cells of different age (5,10, 15, 20, and 25 days old) were treated with a 5% elicitor of A. niger, F. moniliforme, and T. viride and investigated elicitors activity at different age of cell cultures. Maximum yield 166 microg g(-1) DW of ajmalicine was synthesized in 20 day old suspension cultures treated with T. viride. A longer period of incubation of cell cultures with elicitors adversely affected the ajmalicine synthesis.     

Evaluation of filamentous fungi and inducers for the production of endo-polygalacturonase by solid state fermentation

Aspergillus oryzae CCT 3940, Aspergillus awamori NRRL 3112 and a Trichoderma sp.) were compared for their capacity to produce endo-polygalacturonase (endo-PG) in solid state fermentation. Maximum pectinolytic activity was reached in 72 h of growth, the best two fungal strains being A. niger T0005007-2 and A. oryzae CCT 3940. Three types of commercial purified pectin and four of unprocessed pectin (tangerine, orange, Tahiti lime and sweet lime rind) were used to assess the effect of pectin on the production of endo-PG by A. niger T0005007-2. Maximum pectinolytic activity was achieved using 6 and 10% (w/w) of purified pectin as inducer. Depending on the origin of the commercial pectin used as inducer, maximum endo-PG levels varied from 223 to 876 units per gram of dry medium (one endo-PG unit (U) was defined as the quantity of enzyme which caused a reduction in viscosity of 50% in a 1% w/v solution of pectin in 30 min), indicating that care should be taken when choosing this component of the medium. When the crude pectins were used as inducers at the same concentration as purified pectin, maximum endo-PG activities were 250-300 units/g. However, by increasing the amount of Tahiti lime rind to 50% (w/w) maximum endo-PG was 919 U/g, thus opening up the possibility of a low cost medium for endo-PG production.     

A potential resource for bioconversion of domestic wastewater sludge

Twenty seven filamentous fungal strains representing five genera; Aspergillus, Penicillium, Trichoderma, Myriodontium and Pleurotus were isolated from four sources; domestic wastewater sludge cake (SC) from IWK (Indah Water Konsortium) wastewater treatment plant, palm oil mill effluent compost from Sri Ulu palm Oil Processing Mill, compost of plant debris, and fungal fruiting bodies from a rotten wood stump. Thirty-three strains/isolates were tested for their ability to convert domestic wastewater sludge into compost by assessing biomass production and growth rate on sludge enriched media. The strains/isolates Aspergillus niger, SS-T2008, WW-P1003 and RW-P1 512 produced the highest dry biomass at higher sludge supplemented culture media from their respective group (Aspergillus, Trichoderma, Penicillium and Basidiomycetes, respectively). This implied these strains are better adapted for growth at higher sludge rich substances, and subsequently may be efficient in bioconversion/biodegradation of sludge. The fungi isolated from ecological closely related sources were more amendable to adaptation in a sludge rich culture media.     

高絮凝活性霉菌的筛选及其在制革废水中的应用

采用常规分离方法,以高岭土悬液絮凝能力为指标,从活性污泥中筛选霉菌,并对其基本特性和处理制革废水的可行性进行研究。结果获得2株絮凝活性高的霉菌,经初步鉴定为米曲霉(Aspergillus oryzae)和黑曲霉(Aspergillus niger)。对处理制革废水,色度、氨氮、化学需氧量(COD)和铬的去除都有明显效果,宜作为制革废水生物处理的絮凝剂。     

利用天然纤维废弃物发酵生产L-乳酸的研究

为了降低L-乳酸的生产成本,更好的实现生物质秸秆的资源化,利用天然纤维素依次接种经离子注入诱变处理的木聚糖酶高产菌黑曲霉P602和米根霉RL6041高产菌进行固、液体二次发酵的方法,将其转化成用于工业生产的L-乳酸。结果表明:本实验条件下,未经过任何化学预处理的秸秆等物质接种黑曲霉P602进行固体发酵,产生的木聚糖酶活力为6 320 IU/g干(培养)基,纤维素酶活力为29 IU/g干基;加入100 mL水浸提后,产生的还原糖浓度为14.07 g/L,纤维物质糖化率为79.45%。取滤液接入米根霉RL6041进行液体发酵后,生成乳酸的量为7 g/L,糖酸转化率为47.6%,以(NH4)2SO4作为氮源时,最佳氮源浓度为3 g/L。     

Structural features of a polygalacturonase gene cloned from Aspergillus oryzae KBN616

Abstract A genomic gene encoding a polygalacturonase from Aspergillus oryzae , used in soy sauce production, was cloned and sequenced. The structural gene comprises 1227 bp coding for 363 amino acids with a putative prepropeptide of 28 amino acids and the open reading frame is disrupted by two short introns of 57 bp and 81 bp. The deduced amino acid sequence of the mature protein showed 63, 63, 63 and 64% homology with those of Aspergillus niger polygalacturonase I, Aspergillus niger polygalacturonase II, Aspergillus tubingensis polygalacturonase II and Cochliobolus carbonum polygalacturonase, respectively. There is, however, little homology among fungal, plant and bacterial polygalacturonases.     

SCP production and removal of organic load from cassava starch industry waste by yeasts

Wastewater obtained from the cassava processing industry was used to produce single cell protein (SCP). A few selected strains of yeasts were analysed for the SCP production based on the criteria of best biomass yield and high reduction in Chemical Oxygen Demand (COD) under nitrogen limitation. The monoculturing of Candida tropicalis gave the highest μmax with a protein enhancement of 4 fold and 50% decrease in COD. The performance of cocultures have shown an improvement in the COD removal of the wastewater and in the percent increase of protein. The effects of coculturing were better in a lab fermentor under controlled conditions.     

Bio-active composts from rice straw enriched with rock phosphate and their effect on the phosphorous nutrition and microbial community in rhizosphere of cowpea

Composts were produced from rice straw enriched with rock phosphate and inoculated with Aspergillus niger, Trichoderma viride and/or farmyard manure (FYM). The resulting composts were evaluated as organic phosphate fertilizers for cowpea plants in pot experiments. The results showed that the maximum amount of soluble phosphorous (1000 ppm) was produced in composts inoculated with A. niger+T. viride with or without FYM. Any of the produced composts was much better than superphosphate fertilizer in providing the growing cowpea plants with phosphorous. Fertilization of the cowpea plants with the compost inoculated with FYM+A. niger+T. viride resulted in maximum amount of phosphorous uptake (295 ppm). The highest phosphate dissolving fungi numbers in rhizosphere soils of cowpea plants were obtained after fertilization with composts which received A. niger and T. viride treatments, while the highest phosphate dissolving bacterial numbers were found after fertilization with composts which received FYM treatments.     

Effects of some carbon and nitrogen sources on spore germination,production of biomass and antifungal metabolites by species of Trichoderma and Gliocladium virens antagonistic to Sclerotium cepivorum

Conidia of Trichoderma pseudokoningii (IMI 322662) and T. viride (IMI 322659) were incubated in 1% bacteriological peptone at 25° C for 20 h and more than 95% of the spores germinated. In the same medium, only 35% of the conidia of Gliocladium virens (G20) and T. viride (IMI 322663) germinated but when 1% glucose was added, germination was increased to 70%. In the presence of glucose as a carbon source, maximal biomass production of G. virens (G20) after seven days at 25°C was obtained with either potassium nitrate or L‐alanine as the nitrogen source, whereas the Trichoderma isolates needed an organic nitrogen source. With L‐alanine as a nitrogen source, glucose, galactose and sucrose were readily utilized for biomass production by all fungal isolates. Maltose utilization by G. virens (G20) and T. pseudokoningii was incomplete after 21 days incubation, whereas glucose utilization was complete by this time. G. virens, T. pseudokoningii and T. viride (IMI 322663) produced antifungal metabolites which were effective at reducing radial growth of Rhizoctonia solani, Botrytis cinerea as well as S. cepivorum. The metabolites produced by G. virens were very active against all three pathogens but the metabolites produced by T. pseudokoningii and T. viride (IMI 322663) were less active. T. viride (IMI 322659) was a very poor antifungal metabolite producer.     

Mycelial morphology and fungal protein production from starch processing wastewater in submerged cultures of Aspergillus oryzae

Three strains of Aspergillus oryzae were used for fungal protein production from starch processing wastewater (SPW) as part of a comprehensive SPW utilization and treatment program. The mycelial morphologies of the three strains varied from fluffy, clumpy mycelia to compact pellets with various strains and cultivation conditions of growth pH, inoculum quantity and superficial air velocity in an air lift bioreactor process. An inoculum technique was developed to ensure a desirable morphology with an improved fungal protein yield. Experimental relationship between the morphology and the yield revealed that the formation of small compact pellets under designed cultivation conditions favoured higher fungal protein yields, easier product separation and better process operation.     

Fumonisin and ochratoxin production in industrial Aspergillus niger strains

Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B(2), B(4), and B(6)) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also produced fumonisins. Strains optimized through random mutagenesis usually maintained their mycotoxin production capability. Toxigenic strains were also able to produce the toxins on media suggested for citric acid production with most of the toxins found in the biomass, thereby questioning the use of the remaining biomass as animal feed. In conclusion it is recommended to use strains of A. niger with inactive or inactivated gene clusters for fumonisins and ochratoxins, or to choose isolates for biotechnological uses in related non-toxigenic species such as A. tubingensis, A. brasiliensis, A vadensis or A. acidus, which neither produce fumonisins nor ochratoxins.     

Citric acid production by Aspergillus niger on wet corn distillers grains

AIMS: To determine which citric acid-producing strain of Aspergillus niger utilized wet corn distillers grains most effectively to produce citric acid. METHODS AND RESULTS: Citric acid and biomass production by the fungal strains were analysed on the untreated grains or autoclaved grains using an enzyme assay and a gravimetric method respectively. Fungal citric acid production on the grains was found to occur on the untreated or autoclaved grains. The highest citric acid level on the grains was produced by A. niger ATCC 9142. The autoclaved grains supported less citric acid production by the majority of strains screened. Biomass production by the fungal strains on the untreated or autoclaved grains was quite similar. The highest citric acid yields for A. niger ATCC 9142, ATCC 10577, ATCC 11414, ATCC 12846 and ATCC 26550 were found on the untreated grains. Treatment of the grains had little effect on citric acid yields based on reducing sugars consumed by A. niger ATCC 9029 and ATCC 201122. CONCLUSIONS: It is feasible for citric acid-producing strains of A. niger to excrete citric acid on wet corn distillers grains whether the grains are treated or untreated. The most effective citric acid-producing strain of A. niger was ATCC 9142. SIGNIFICANCE AND IMPACT OF THE STUDY: The study shows that the ethanol processing co-product wet corn distillers grains could be utilized as a substrate for the commercial production of citric acid by A. niger without treatment of the grains.