Microfloral contamination and hydrolytic enzyme differences between monsooned and non-monsooned coffees

AIMS: To analyse and compare, for the first time, fungal and bacterial populations and hydrolytic enzyme production in four monsooned and non-monsooned Arabica and Robusta coffee types. METHODS AND RESULTS: Overall, using serial dilution, the populations of bacteria (approximately 10(8) cfu g(-1)) were highest in monsooned coffees of both varieties. Fungal populations were lower (10(5) cfu g(-1)) and found predominantly on monsooned coffee beans. The major fungal species were Aspergillus terreus, A. restrictus and A. ochraceus. Of 19 semi-quantitative enzymes analysed, significantly higher concentrations of 2-naphthyl-butyrate, caprylate and 2-naphthyl-D-galactopyranosidase were present in Arabica monsooned coffee. CONCLUSIONS: The results suggest that speciality monsooned coffee has markedly different microbial and physiological characteristics from normally produced green coffees. SIGNIFICANCE AND IMPACT OF THE STUDY: Monsooned coffee may have a higher contamination with spoilage moulds, especially mycotoxigenic species.     

Ochratoxin A-producing Aspergilli in Vietnamese green coffee beans

AIMS: To determine the incidence and severity of infection by ochratoxin A (OA)-producing fungi in Vietnamese green coffee beans. METHODS AND RESULTS: Aspergillus carbonarius, A. niger and yellow Aspergilli (A. ochraceus and related species in section Circumdati) were isolated by direct plating of surface-disinfected Robusta (65 samples) and Arabica (11 samples) coffee beans from southern and central Vietnam. Significantly, more Robusta than Arabica beans were infected by fungi. Aspergillus niger infected 89% of Robusta beans, whereas A. carbonarius and yellow Aspergilli each infected 12-14% of beans. OA was not produced by A. niger (98 isolates) or A. ochraceus (77 isolates), but was detected in 110 of 113 isolates of A. carbonarius, 10 isolates of A. westerdijkiae and one isolate of A. steynii. The maximum OA observed in samples severely infected with toxigenic species was 1.8 microg kg(-1); however, no relationship between extent of infection and OA contamination was observed. CONCLUSIONS: Aspergillus niger is the dominant species infecting Vietnamese coffee beans, yet A. carbonarius is the likely source of OA contamination. SIGNIFICANCE AND IMPACT OF STUDY: Vietnamese green coffee beans were more severely infected with fungi than the levels reported for beans from other parts of the world, yet OA contamination appears to be infrequent.     

Packed bed column fermenter and kinetic modeling for upgrading the nutritional quality of coffee husk in solid-state fermentation.

Studies were carried out to evaluate solid-state fermentation (SSF) for the upgradation of the nutritional quality of coffee husk by degrading the caffeine and tannins present in it. SSF was carried out by Aspergillus niger LPBx in a glass column fermenter using factorial design experiments and surface response methodology to optimize bioprocess parameters such as the substrate pH and moisture content and aeration rate. The first factorial design showed that the moisture content of the substrate and aeration rate were significant factors for the degradation of toxic compounds, which was confirmed by the second factorial design too. The kinetic study showed that the degradation of toxic compounds was related to the development of the mold and its respiration and also to the consumption of the reducing sugars present in coffee husk. From the values obtained experimentally for the oxygen uptake rate and CO(2) evolved, the system determined a biomass yield (Y(x/o)) of 3.811 (g of biomass).(g of consumed O(2))(-1) and a maintenance coefficient (m) of 0.0031 (g of consumed O(2)).(g biomass of biomass)(-1).h(-1). The best results on the degradation of caffeine (90%) and tannins (57%) were achieved when SSF was carried out with a 30 mL.min(-1) aeration rate using coffee husk having a 55% initial moisture content. The inoculation rate did not affect the metabolization of the toxic compounds by the fungal culture. After SSF, the protein content of the husk was increased to 10.6%, which was more than double that of the unfermented husk (5.2%).     

Supplementation of waste tea fungal biomass as a dietary ingredient for broiler chicks

The waste tea fungal biomass produced during black tea fermentation was investigated as a dietary ingredient in poultry feeds. A small portion of fungal mat was used as starter culture for the next cycle while the major portion is discarded as waste. Hence a trial study was carried out to utilize the waste fungal biomass as a supplementary diet for broiler chicks. The fungal biomass contained 179.38 g of crude protein, 120 g crude fibre, 4.82 g phosphorus, 6.56 g of calcium and 8.92 MJ metabolizable energy per kilogram of biomass. The dried tea fungus showed phytase activity of 23 IU/mg protein. The supplementation of tea fungal inclusion (TFI) at 150 g/kg concentration in poultry feed increased the feed consumption, body weight, performance efficiency factor (PEF) and the carcass characters of test broilers significantly (P=0.01) over the control. The histopathological examination of liver showed no abnormalities and the mortality rate was zero.     

Genetic relationships among Brazilian strains of Aspergillus ochraceus based on RAPD and ITS sequences

Ochratoxin A (OA) is a mycotoxin that has been found in coffee beans and coffee beverages. Its toxicological profile includes carcinogenicity, nephrotoxicity, and immunotoxicity. Aspergillus ochraceus is the major species responsible for OA production in Brazilian coffee beans. The genetic relationships among 25 A. ochraceus strains collected from Brazilian coffee-bean samples were determined based on RAPD and internal transcribed spacer (ITS) sequence data. The isolates were resolved into 2 distinct groups, one with 4 strains (group A) and the other with 21 strains (group B). Specific nucleotide variations characterizing group A and B were found for both ITS1 and ITS2 regions. Group B is a new group proposed here to accommodate the majority of the Brazilian isolates. Each group was found to contain both toxigenic and nontoxigenic strains, indicating that there is no association between molecular genotypes and the ability to produce OA.     

Influence of neuropeptide Y (NPY) on food intake and growth of penaeid shrimps Marsupenaeus japonicus and Penaeus semisulcatus (Decapoda: Penaeidae)

The effects of neuropeptide Y (NPY) administered intramuscularly or orally on postlarvae (PLs) of two penaeid species were investigated in this study. In experiment 1, food intake (FI) of Marsupenaeus japonicus PLs (0.96 g), injected with NPY at 0.6 microg per g BW, was investigated within 48 h posttreatment. In experiment 2, oral administration of NPY (at doses of 0, 0.125, 0.25, 0.5 microg g(-1) food) on feed intake and growth performance of Penaeus semisulcatus PLs (0.27 g) was examined for 6 weeks. In experiment 1, NPY injection significantly increased average daily FI of M. japonicus PLs within the first 24 h compared to the control (P<0.05), but its stimulatory effect decreased on the second day (P>0.05). The increase in FI was 33% during the first 24 h and 17% during the next 24 h. In experiment 2, significant (P<0.05) differences were found among the groups in terms of weight gain and food utilization (P<0.05). Mean FI significantly increased (as much as 1.3-fold over the control) when NPY was orally administered at doses from 0.125 to 0.5 microg g(-1) feed. There was a positive relationship between FI and final weight (y=-0.972+2.098x, R(2)=0.81) and between FCE and NPY doses in the diets (y=45.37+3.46x, R(2)=0.91). The present findings indicated for the first time that NPY is a potent stimulator of food intake when administered either intramuscularly or orally to penaeid shrimps.     

Bioavailability and pharmacokinetics of a praziquantel bolus in kingfish Seriola lalandi

Oral praziquantel (PZQ) preparations have recently been investigated for the treatment of monogeneans that infect the skin and gills of kingfish Seriola lalandi cultured in sea-cages. To evaluate an oral PZQ dosing strategy, the pharmacokinetics of a dissolved and in feed oral PZQ preparation (40 mg kg(-1) body weight) were compared with an intravenous bolus in kingfish plasma and skin using HPLC. Compared with intravenous administration, PZQ bioavailability (area under curve, AUC0-24h) was slightly improved when the drug was administered with food in both kingfish plasma (56.8% in feed vs. 50.8% in solution) and skin (55.5% in feed vs. 50.3% in solution). After oral dosing, maximum drug concentrations in skin were approximately one-third of those achieved in plasma and higher when the drug was administered in solution (5.26 microg ml(-1)) than in feed (3.96 microg ml(-1)); additionally, the time to achieve maximum PZQ concentration was similar in plasma and skin, although markedly reduced when the drug was administered in solution (1 h) than in feed (6 h). However, clearance of the drug was delayed in skin; administered as an oral formulation, PZQ concentrations in the systemic circulation fell below the limit of quantification after 24 h, but remained quantifiable (0.3 microg g(-1)) in skin at this time. These initial studies indicate that a daily treatment interval will lead to the exposure of parasites to highly variable anthelmintic concentrations, which may be sub-optimal for the treatment of monogeneans in this finfish species.     

Diets of the African Civet Civettictis civetta (Schreber, 1778) in selected coffee forest habitat,south‐western Ethiopia

Feeding ecology of the African civet, Civettictis civetta (Schreber, 1778), was studied in selected coffee forest habitat for two seasons between December 2012 and October 2013. The study was conducted in Limu Seka district, south‐west Ethiopia. Faecal analysis was employed to assess the diet spectrum, seasonal abundance and relative importance of food items. Over 55 different food items were identified from the analysis of 387 scat samples collected during the dry and wet seasons. In the coffee forest habitat, African civets showed omnivorous feeding habit with plant‐to‐animal diet biomass ratio of 1 : 1.36. A slight diet specialization was observed during the wet season (BA = 0.46) favouring animal prey. However, during the dry season, they showed generalist feeding habit (BA = 0.87) with more plant biomass in their diet. With over 64% occurrence and 14.4% biomass, coffee berries significantly contributed to the civets dry season plant diets. The excreted coffee beans, after civets ingested ripe coffee berries, are the tastiest product used by farmers for consumption and market. Seasonal collection of civet coffee from coffee forest floor economically supports the farmers while increasing the importance of civets in the habitat and hence contributing for its conservation.     

Changes in biomass, chemical composition and nutritive value of Spartina alterniflora due to organic pollution in the Itanhaém River Basin (SP, Brazil).

We compared the values of the biomass, chemical composition and nutritive value of the emergent aquatic macrophyte S. alterniflora in a river affected by the discharge of domestic sewage (Guaú River) and in an unpolluted river (Itanhaém River). S. alterniflora, water and sediment samples were obtained in the two rivers in November, 2001. The Guaú River presented the highest levels of Total-N and Total-P in the water (415 and 674 microg.L(-1), respectively) and in the sediment (0.25 e 0.20% of the Dry Mass, respectively), when compared to the water (TN = 105 microg.L(-1); TP = 20 microg.L(-1)) and the sediment (NT = 0.12% DM; PT = 0.05% DM) of the Itanhaém River. Aerial (316 g DM.m(-2)) and subterraneous (425 g DM.m(-2)) biomass of S. alterniflora were significantly higher in the Guaú River than in the Itanhaém River (146 and 115 g DM.m(-2), respectively). In addition, the values of TN, protein, TP, lipids and soluble carbohydrates were significantly higher in S. alterniflora biomass from the Guaú River. On the other hand, the values of the polyphenols and the cell wall fraction were significantly higher in the biomass of S. alterniflora from the Itanhaém River. We concluded that domestic sewage discharge in water bodies may increase the biomass and change the chemical composition of S. alterniflora. The high N and P availability in the water of the Guaú River is probably the cause of the higher biomass, TN, TP, protein, lipids and soluble carbohydrates measured in S. alterniflora in this river.     

Kinetics of Gibberella fujikuroi growth and gibberellic acid production by solid-state fermentation in a packed-bed column bioreactor

In this work the growth of Gibberella fujikuroi and gibberellic acid (GA3) production were studied using coffee husk and cassava bagasse as substrates in a packed-bed column bioreactor connected to a gas chromatograph for exit gas analysis. With the respirometric data, a logarithmic correlation between accumulated CO2 and biomass production was determined, and the kinetics of the fungal growth was compared for estimated and experimental data. The solid medium consisted of coffee husk (pretreated with alkali solution), mixed with cassava bagasse (7:3 dry weight basis), with a substrate initial pH of 5.2 and moisture of 77%. Cultivation was carried out in glass columns, which were packed with preinoculated substrate and with forced aeration of 0.24 L of air/[h (g of substrate)] for the first 3 days, and 0.72 L of air/[h (g of substrate)] for the remaining period. The maximum specific growth rate (microm) obtained was 0.052 h(-1) (between 24 and 48 h of fermentation). A production of 0.925 g of GA3/kg of substrate was achieved after 6 days of fermentation.     

Analysis of amino acids and carbohydrates in green coffee

The analysis of carbohydrates and amino acids in green coffee is of the utmost importance since these two classes of compounds act as precursors of the Maillard reaction during which the colour and aroma are formed. During the course of the Maillard reaction potentially harmful substances like acrylamide or 5-hydroxymethyl-furfural accrue as well. The carbohydrates were analysed by anion-exchange chromatography with pulsed amperometric detection and the amino acids by reversed phase chromatography after derivatization with 6-amino-quinolyl-N-hydroxysuccinimidyl carbamate and fluorescence detection. Both methods had to be optimized to obtain a sufficient resolution of the analytes for identification and quantification. Sucrose is the dominant carbohydrate in green coffee with a concentration of up to 90 mg/g (mean = 73 mg/g) in arabica beans and significantly lower amounts in robusta beans (mean=45 mg/g). Alanine is the amino acid with the highest concentration (mean = 1200 microg/g) followed by asparagine (mean = 680 microg/g) in robusta and 800 microg/g and 360 microg/g in arabica respectively. In general, the concentration of amino acids is higher in robusta than in arabica.     

Relations Between Biomass Accumulation and Infection by Vesicular-Arbuscular Mycorrhizal Fungi in Cassava as Affected by Planting Date

Roots of 12, 3-month-old, field-propagated clones of cassava (Manihot esculenta Crantz) were more heavily mycorrhizal in the dry (Jan.–March and Oct.–Dec.) (39–83 %) than in the wet season (April–Sept.) (20–71%). Mean dry weights (biomass) of roots and shoots in the wet season (3.8–7.9 and 9.7–19.1 g/plant) were higher (P = 0.01) than in the dry season (2.1–5.9 and 5.4–12.8 g/plant, respectively). Clones with symptoms of the African cassava mosaic disease (ACMD) were less mycorrhizal, (20–69%) than mosaic symptom-free clones (51–83%). Higher colonization of roots of the clones by indigenous fungal symbionts and lower biomass accumulation in the dry season are attributed mainly to soil moisture and other effects, while reduced infections in cassava with ACMD symptoms may be due to ACMD-induced reductions in carbohydrate levels.     

荒漠植物根际AM真菌的空间分布和定殖

 通过分析以色列荒漠地区Zygophyllum dumosum, Hammada scoparia, Artemisia herba-alba 和 Atriplex halimus 等4种灌木根际AM真菌的空间分布和定殖程度,研究了AM真菌分布和定殖与植物种类和土壤因子间的相关性。样品分别从0～10 cm,10～20 cm,20～30 cm,30～40 cm和40～50 cm等5个土层中采取,土样过2 mm筛。收集的根样切成1 cm根段,经染色后,根据感染长度确定AM真菌不同结构的定殖率;用湿筛倾析法和蔗     

Growth and production of biomass of Rhodovulum sulfidophilum in sardine processing wastewater

AIMS: Rhodovulum sulfidophilum was grown in sardine processing wastewater to assess growth characteristics for the production of bacterial biomass with simultaneous reduction of chemical oxygen demand. METHODS AND RESULTS: Growth characteristics were compared in diluted and undiluted, settled and non-settled wastewater growing in anaerobic light and aerobic dark conditions; and also at different agitation speeds. The highest biomass (8.75 g l(-1)) and a reduction in chemical oxygen demand of 71% were obtained in unsettled, undiluted wastewater after 120 h culture with 15% inoculum. In settled wastewater, highest biomass (7.64 g l(-1)) and a COD reduction of 77% was also obtained after 120 h. Total biomass was higher (4.34 g l(-1)) after 120 h culture in anaerobic light compared to (3.23 g l(-1)) in aerobic dark growth. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Better performance, mean of total biomass (6.97 g l(-1) after 96 h), total carotenoids (4.24 mg g(-1) dry cell from 24 h) and soluble protein (431 microg ml(-1) after 96 h) were obtained from aerobic dark culture at 300 rev min(-1). The COD reduction, however, was lower (69%) after 96 h culture. Thus, the benefits in the production of bacterial biomass in non-sterilized sardine processing wastewater with the reduction of chemical oxygen demand could be achieved.     

Effect of the nitrogen source on caffeine degradation by Aspergillus tamarii

AIMS: To evaluate caffeine degradation and nitrogen requirements during Aspergillus tamarii growth in submerged culture. METHODS AND RESULTS: Aspergillus tamarii spores produced on a coffee infusion agar medium added with sucrose were used. Several caffeine and ammonium sulphate concentrations (0-1 and 0-1.36 g l-1, respectively) were tested simultaneously on fungal biomass production and caffeine degradation. An additional caffeine pulse (4 g l-1) was added for all experiments after 48 h of fermentation. Results revealed that when using 0.90 g l-1 of caffeine and 0.14 g l-1 of ammonium sulphate, biomass production and caffeine degradation were enhanced. Highest biomass production (Xmax = 9.87 g l-1) with a specific growth rate (micro) of 0.073 h-1 and caffeine degradation rate of 0.033 g l-1 h-1, was observed under these conditions. CONCLUSIONS: Caffeine degradation as well as biomass production were characterized. SIGNIFICANCE AND IMPACT OF THE STUDY: These studies set the stage for future characterization studies of intracellular enzymes involved in caffeine degradation. Moreover, results observed may help in the biotreatment of residues from the coffee agroindustry.     

Accelerated coffee pulp composting

The effect of two abundant, easily available and very low-cost agro-industrial organic residues, i.e., filter cake from the sugar industry and poultry litter, on the composting stabilization time of coffee pulp and on the quality of the produced compost, was evaluated. Piles of one cubic meter were built and monitored within the facilities of a coffee processing plant in the Coatepec region of the State of Veracruz, Mexico. Manual aeration was carried out once a week. A longer thermophilic period (28 days) and a much lower C/N ratio (in the range of 6.9–9.1) were observed in the piles containing the amendments, as compared to the control pile containing only coffee pulp (14 days and a C/N ratio of 14.4, respectively). The maximum assimilation rate of the reducing sugars was 1.6 g kg-1 d-1 (from 7.5 to 5.3%) during the first two weeks when accelerators were present in the proportion of 20% filter cake plus 20% poultry litter, while they accumulated at a rate of 1.2 g kg-1 d-1 (from 7.4 to 9.13%) during the same period in the control pile. The best combination of amendments was 30% filter cake with 20% poultry litter, resulting in a final nitrogen content as high as 4.81%. The second best combination was 20% filter cake with 10% poultry litter, resulting in a compost which also contained a high level of total nitrogen (4.54%). It was concluded that the use of these two residues enhanced the composting process of coffee pulp, promoting a shorter stabilization period and yielding a higher quality of compost.     

Fungal growth, production, and sporulation during leaf decomposition in two streams.

I examined the activity of fungi associated with yellow poplar (Liriodendron tulipifera) and white oak (Quercus alba) leaves in two streams that differed in pH and alkalinity (a hard water stream [pH 8.0] and a soft water stream [pH 6.7]) and contained low concentrations of dissolved nitrogen (<35 microg liter(-1)) and phosphorus (<3 microg liter(-1)). The leaves of each species decomposed faster in the hard water stream (decomposition rates, 0.010 and 0.007 day(-1) for yellow poplar and oak, respectively) than in the soft water stream (decomposition rates, 0.005 and 0.004 day(-1) for yellow poplar and oak, respectively). However, within each stream, the rates of decomposition of the leaves of the two species were not significantly different. During the decomposition of leaves, the fungal biomasses determined from ergosterol concentrations, the production rates determined from rates of incorporation of [(14)C]acetate into ergosterol, and the sporulation rates associated with leaves were dynamic, typically increasing to maxima and then declining. The maximum rates of fungal production and sporulation associated with yellow poplar leaves were greater than the corresponding rates associated with white oak leaves in the hard water stream but not in the soft water stream. The maximum rates of fungal production associated with the leaves of the two species were higher in the hard water stream (5.8 mg g(-1) day(-1) on yellow poplar leaves and 3.1 mg g(-1) day(-1) on oak leaves) than in the soft water stream (1.6 mg g(-1) day(-1) on yellow poplar leaves and 0.9 mg g(-1) day(-1) on oak leaves), suggesting that effects of water chemistry other than the N and P concentrations, such as pH or alkalinity, may be important in regulating fungal activity in streams. In contrast, the amount of fungal biomass (as determined from ergosterol concentrations) on yellow poplar leaves was greater in the soft water stream (12.8% of detrital mass) than in the hard water stream (9.6% of detrital mass). This appeared to be due to the decreased amount of fungal biomass that was converted to conidia and released from the leaf detritus in the soft water stream.     

Biological detoxification of coffee husk by filamentous fungi using a solid state fermentation system

Studies were carried out on detoxification of coffee husk in solid state fermentation using three different strains of Rhizopus, Phanerochaete, and Aspergillus sp. Fungal strains were selected by their ability to grow on a coffee husk extract-agar medium. Using R. arrizus LPB-79, the best results on the degradation of caffeine (87%) and tannins (65%) were obtained with pH 6.0 and moisture 60% in 6 days. When P. chrysosporium BK was used, maximum degradation of caffeine and tannins were 70.8 and 45%, respectively, with coffee husk having 65% moisture and pH 5.5 in 14 days. The Aspergillus strain, isolated from the coffee husk, showed best biomass formation on coffee husk extract-agar medium. Optimization assays were conducted using factorial design, and surface response experiments with Aspergillus sp. The best detoxification rates achieved were 92% for caffeine and 65% for tannins. The results showed good prospects of using these fungal strains, in particular Aspergillus sp., for the detoxification of coffee husk.     

Host species and strain combination determine growth reduction of spruce and birch seedlings colonized by root-associated dark septate endophytes

Interactions of Betula pendula and Picea abies with dark septate endophytes of the Phialocephala fortinii-Acephala applanata species complex (PAC) were studied. PAC are ubiquitous fungal root symbionts of many woody plant species but their ecological role is largely unknown. Sterile birch and spruce seedlings in monoculture and mixed culture were exposed to four PAC strains, added either singularly or paired in all possible combinations at 18°C and 23°C. Plant and fungal biomass was determined after 4 months. The most significant factors were strain and host combination. One of the strains significantly reduced biomass gain of spruce but not of birch. Plant biomass was negatively correlated with total endophytic fungal biomass in half of the strain - plant combinations. Endophytic PAC biomass was four times higher in spruce (≈ 40 mg g(-1) drw) than in birch (≈ 10 mg g(-1) drw). Competition between strains was strain-dependent with some strains significantly reducing colonization density of other strains, and, thus, attenuating adverse effects of 'pathogenic' strains on plant growth in some strain - plant combinations. Biomass gain of spruce but not of birch was significantly reduced at higher temperature. In conclusion, host, fungal genotype, colonization density and presence of a competing PAC strain were the main determining factors for plant growth.     

Kinetics of batch ethanol fermentation of cheese-whey powder (CWP) solution as function of substrate and yeast concentrations

A lactose utilizing yeast strain, Kluyveromyces marxianus DSMZ-7239 was used for ethanol formation from cheese-whey powder (CWP) solution in batch experiments. Effects of initial substrate (CWP) and yeast concentrations on the rate and extent of ethanol formation were investigated. The initial pH and oxidation-reduction potential (ORP) was kept at 5 and -250 mV, respectively. The rate and extent of ethanol formation increased with increasing CWP concentration up to 156 g l(-1) (75 g l(-1) sugar) and then decreased for larger CWP concentrations due to substrate inhibition at high sugar concentrations. The ethanol yield coefficient was also maximum (0.54 g EtOH/g sugar) and equal to the theoretical yield at CWP concentration of 156 g l(-1). The growth yield coefficient was found to be Y(x/s)=1.2+/-0.1g biomass g sugar(-1). The rate of sugar utilization and ethanol formation also increased linearly with increasing initial biomass concentrations. A kinetic model describing the rate of sugar utilization and substrate inhibition as function of the initial substrate and the biomass concentrations was developed. The kinetic constants were determined using the experimental data. Model predictions of sugar utilization rates were in good agreement with the experimental data. The results indicated that the initial sugar concentration should be below 75 g l(-1) (CWP<156 g l(-1)) and the initial biomass should be above 850 mg l(-1) to obtain high rates and yields of ethanol formation and to avoid substrate inhibition.