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Microbial oils are regarded as a sustainable alternative to vegetable oils for biodiesel manufacturing. However, in order to develop a cost-effective process, high-lipid producer microorganisms should be combined with low-cost renewable growth substrates. For this reason, the objective of the present study was to assess comparatively the oil-producing performance of 9 oleaginous fungi belonging to the Aspergillus, Mucor, Mortierella and Cunninghamella genera on three relevant and widespread waste, such as glycerol, orange peel extract (OPE) and ricotta cheese whey (RCW). This screening was performed at the shaken flask level and, among the strains under study, Mortierella isabellina NRRL 1757 turned out to be the most efficient and versatile and its lipid profile was found to be highly compatible with biodiesel production. Process transfer of M. isabellina lipid production to the lab-scale Stirred Tank Reactor on all the three waste-based media, was shown to be feasible, achieving a lipid productivity of 0.46, 1.24 and 0.91 g/(L d) on glycerol, OPE and RCW, respectively. Noteworthy, the fatty acid analysis of the oils produced, confirmed their suitability for biodiesel manufacturing, exhibiting a high similarity to palm and Jatropha oils commonly used as feedstock for this production.

The objective of this work was to test the PCB-degrading abilities of two white-rot fungi, namely Pleurotus ostreatus and Irpex lacteus, in real contaminated soils with different chemical properties and autochthonous microflora. In addition to the efficiency in PCB removal, attention was given to other important parameters, such as changes in the toxicity and formation of PCB transformation products. Moreover, structural shifts and dynamics of both bacterial and fungal communities were monitored using next-generation sequencing and phospholipid fatty acid analysis. The best results were obtained with P. ostreatus, which resulted in PCB removals of 18.5, 41.3 and 50.5% from the bulk, top (surface) and rhizosphere, respectively, of dumpsite soils after 12 weeks of treatment. Numerous transformation products were detected (hydoxylated and methoxylated PCBs, chlorobenzoates and chlorobenzyl alcohols), which indicates that both fungi were able to oxidize and decompose the aromatic moiety of PCBs in the soils. Microbial community analysis revealed that P. ostreatus efficiently colonized the soil samples and suppressed other fungal genera. However, the same fungus substantially stimulated bacterial taxa that encompass putative PCB degraders. The results of this study finally demonstrated the feasibility of using this fungus for possible scaled-up bioremediation applications.

The removal of aged hydrophobic contaminants from fine-textured soils is a challenging issue in remediation. The objective of this study was to compare the efficacy of augmentation treatments to that of biostimulation in terms of total aliphatic hydrocarbon (TAH) and toxicity removal from a historically contaminated clay soil and to assess their impact on the resident microbial community. To this aim, Pleurotus ostreatus , Botryosphaeria rhodina and a combination of both were used as the inoculants while the addition of a sterilized lignocellulose mixture to soil (1:5, w / w ) was used as a biostimulation approach. As opposed to the non-amended control soil, where no changes in TAH concentration and residual toxicity were observed after 60 days, the activation of specialized bacteria was found in the biostimulated microcosms resulting in significant TAH removal (79.8%). The bacterial community structure in B. rhodina -augmented microcosms did not differ from the biostimulated microcosms due to the inability of the fungus to be retained within the resident microbiota. Best TAH removals were observed in microcosms inoculated with P. ostreatus alone ( Po ) and in binary consortium with B. rhodina (BC) (86.8 and 88.2%, respectively). In these microcosms, contaminant degradation exceeded their bioavailability thresholds determined by sequential supercritical CO 2 extraction. Illumina metabarcoding of 16S rRNA gene showed that the augmentation with Po and BC led to lower relative abundances of Gram(+) taxa, Actinobacteria in particular, than those in biostimulated microcosms. Best detoxification, with respect to the non-amended incubation control, was found in Po microcosms where a drop in collembola mortality (from 90 to 22%) occurred. At the end of incubation, in both Po and BC, the relative abundances of P. ostreatus sequences were higher than 60% thus showing the suitability of this fungus in bioaugmentation-based remediation applications.

Arundo donax L. has received much attention from researchers as biomass crop because of its vigorous growth, high productivity and low agronomic inputs requirements. Once harvested, the chopped biomass of A. donax L. may be stored for a variable period according to energy demand or logistic reasons. As consequence of storage, the chopped biomass may undergo processes of degradation that can compromise the energy yield of the product and the economic convenience of the cultivation. In the view of preserving the A. donax L. biomass for producing different kind of energy, such as bio-ethanol, biogas, and fuel for combustion, the aim of this study was to investigate, in small-scale, different storage systems assessing the dynamics of storage and their effects on energy losses and fuel quality. The work has included different studies, such as (i) the monitoring of heat development, moisture content and dry matter losses, (ii) the analysis of polymeric compounds and combustion performances. Results indicate that according to the storage method adopted, the conservation of the product can be significantly influenced, with clear impacts on its energy potential. Polymeric composition changed after storage according to the method used, while energetic characteristics were not remarkably affected.

An experimental biofuel wood chip storage site was studied, as a potential fungal “reservoir,” by means of quantitative and qualitative assessments of airborne fungal spores. Fungal load in the bio-aerosol, determined through active and passive methods, declined with the distance from wood piles. Occupational exposure was comparatively evaluated when two specific operational tasks, manual and mechanized handling, were performed. Under the conditions tested, the manual operators were more exposed to the airborne fungal spores (4864 ± 580 CFU m−3 air). The collected spores were identified as belonging to species of the genera Alternaria, Aspergillus, Penicillium, Fusarium, Cladosporium, Pleospora, Cochliobolus, Epicoccum, Absidia, and Trichoderma. Most prevalent were the genera Alternaria and Cladosporium, with the highest percentages of occurrence (30 and 12%, respectively). To the best of our knowledge, this is the first work reporting the identification through molecular methods of airborne fungi released during the handling of wood chip biofuel biomass.

Orange peel waste (OPW) was converted into ethanol by consecutive acid-catalysed steam-explosion (ACSE), enzymatic saccharification and fermentation with Saccharomyces cerevisiae F15. The first step was performed in the presence of 0.5% (volume fraction) sulphuric acid at a solid loading of 160 g L−1 using a novel laboratory-scale Direct Steam-Injection Apparatus under different reaction temperatures and times. ACSE at 200 °C for 90 s (or 180 °C for 150 s) yielded the highest solubilization of pectin (∼73%) and a positive effect on the subsequent enzymatic hydrolysis step, that was carried out at 50 °C with an enzyme loading of 6 FPU g−1 cellulose. OPW, pretreated at 180 °C for 150 s, yielded the highest glucose solubilisation degree (∼56%) at the end of the saccharification step, and the maximum ethanol yield coefficient (∼0.495 g g−1) and productivity (4.85 g L−1 h−1) at the end of the 3rd repeated fermentation batch in shaken-flasks.

Three different Tamarix species, namely Tamarix aphylla, T. aphylla “Erect”-type and Tamarix jordanis, were grown in an experimental field under extreme desert conditions and irrigated with either reclaimed sewage or brackish water. Depending on both species and source of irrigation, the above-ground biomass production ranged from 18 to 36 Mg ha−1 in the first year. Among the three chemically characterized Tamarix species, T. jordanis was selected due to its higher cellulose content, and lower hemicellulose and phenol contents so as to outline a preliminary process flow sheet for ethanol production. This included steam-injection heating under acidic conditions (200 °C; 90 s; 0.5% H2SO4; 160 g L−1 solid loading) using a novel lab-scale Direct Steam Injection Apparatus, enzymatic saccharification (50 °C; pH 5.0; 200 g L−1 solid loading; 20 FPU g−1 cellulose) and subsequent ethanolic fermentation (30 °C; Saccharomyces cerevisiae F-15 as the inoculum). Lab-scale fermentation runs were carried out in a 3-L stirred bioreactor in repeated-batch mode and showed an almost quantitative conversion of glucose into ethanol (0.507 ± 0.006 g g−1), thus leading to a satisfactory overall process ethanol yield of about 145 L Mg−1 Tamarix biomass.

An industrial three-cascade-reactor plant treating 45 m3 d−1 of dairy wastewater (DW) was monitored for approx. one year to investigate the effect of variable daily influent loads. It removed more than 85% COD, NH4-N and non-ionic and anionic surfactants from DW within the loads 7–24, 0.4–2.3, 0.4–0.7 and 0.1–0.5 kg d−1, respectively; NH4-N removal, in particular, was almost quantitative. Although the degradation of the above parameters below the lower load thresholds declined to 78.7, 87.5, 50.2 and 64.7%, respectively, their residual concentrations met effluent discharge standards. The biomass settling properties, assessed as sludge volume index (SVI), were satisfactory (generally lower than 150 ml g−1) regardless of the organic load of the influent. The depletion of the pollutant load took mainly place in the first reactor albeit a significant contribution to the removal of the slowly degradable organic matter fraction was given by the two subsequent reactors.

The main aim of this study was to assess the ability of producing extracellular phenoloxidases (EPO) of fungi isolated from olive brine wastewater (OBW), the effluent from the debittering process of table olives. Five out of twenty isolates displayed EPO-producing ability as assessed by selective agar plate assays and were all halotolerant. Among them, Citeromyces matritensis (syn. Candida globosa) and Aspergillus fumigatus concomitantly produced laccase and Mn-peroxidase (MnP) activities. Candida boidinii and Candida bombi, instead, only produced laccase and Candida diddensiae only released MnP. Both C. matritensis and A. fumigatus, grown in shaken cultures on OBW, maintained their EPO-producing ability and removed phenols by 52.3 and 82.3%, respectively, after 10 d incubation in the non-supplemented effluent. These results might suggest the possible use of these strains in the treatment of other saline phenol-rich effluents, such as pickling and tannery wastewater.

The low moisture content of the dry olive mill residue (DOR), solid waste from the two-phase olive oil extraction process, enables its long-term storage and its ready reconstitution with water thus leading to a candidate liquid growth medium for the microbial production of enzymes of commercial interest. To test this hypothesis, two white-rot fungi (WRF), namely Lentinus tigrinus CBS 577.79 and Phlebia sp. DABAC 9, were grown in shaken cultures on non-supplemented aqueous extracts of the dry olive mill residue (ADOR) and compared for their ability to grow therein and produce Mn-dependent peroxidase (MnP). Then, in order to assess the feasibility of scale transfer to the reactor level, the two fungi were grown in a 3-L bubble-column reactor on 25% (w/v) ADOR at 28 °C and an aeration rate of 0.3 vvm. Under these conditions, L. tigrinus and Phlebia sp. produced 42.60 ± 1.74 and 38.88 ± 1.68 nkatal mL −1 MnP with respective mean volumetric productivities of 222.9 and 324.1 nkatal L −1 h −1 . These results clearly show that the use of non-supplemented ADOR as a production medium enables a significant MnP production thus representing an excellent basis for process optimization.

In this work, a novel laboratory-scale direct steam-injection apparatus (DSIA) was developed to overcome the main drawback of the conventional batch-driven lab rigs, namely the long time needed to heat fiber slurry from room to reaction temperatures greater than 150 °C. The novel apparatus mainly consisted of three units: (i) a mechanically-stirred bioreactor where saturated steam at 5-30 bar can be injected; (ii) an automatic on-off valve to flash suddenly the reaction medium after a prefixed reaction time; (iii) a cyclone separator to recover the reacted slurry. This system was tested using 0.75 dm³ of an aqueous solution of H₂SO₄ (0.5%, v/v) enriched with 50 kg m⁻³ of either commercial particles of Avicel® and Larch xylan or 0.5 mm sieved particles of Tamarix jordanis. Each slurry was heated to about 200 °C by injecting steam at 28 bar for 90 s. The process efficiency was assessed by comparing the dissolution degree of suspended solid (Y(S)), as well as xylose (Y(X)), glucose (Y(G)), and furfural (Y(F)) yields, with those obtained in a conventional steam autoclave at 130 °C for 30 or 60 min. Treatment of T. jordanis particles in DSIA resulted in Y(S) and Y(G) values quite similar to those obtained in the steam autoclave at 130 °C for 60 min, but in a less efficient hemicellulose solubilization. A limited occurrence of pentose degradation products was observed in both equipments, suggesting that hydrolysis predominated over degradation reactions. The susceptibility of the residual solid fractions from DSIA treatment to a conventional 120 h long cellulolytic treatment using an enzyme loading of 5.4 FPU g⁻¹ was markedly higher than that of samples hydrolysed in the steam autoclave, their corresponding glucose yields being equal to 0.94 and 0.22 g per gram of initial cellulose, respectively. Thus, T. jordanis resulted to be a valuable source of sugars for bioethanol production as proved by preliminary tests in the novel lab rig developed here.

The short-term response of the resident soil bacterial and fungal communities to the addition of 5% (w/w) of either dry olive mill residue (DOR), DOR treated with Phlebia sp. (PTDOR) or DOR previously extracted with water (WEDOR) was investigated. As opposed to bacteria, the diversity of fungi increased upon the amendments as assessed by denaturing gradient gel electrophoresis of 18S rDNA. Over the first 30 days, phospholipid fatty acids analyses indicated a gradual decrease in the relative abundances of Gram+ bacteria (from 44.8% to 37.9%) and a concomitant increase of Gram- bacteria (from 37.3% to 51.2%) in DOR-amended soil. A considerable increase in the fungal/bacterial ratio was observed after 7 days in DOR, WEDOR and PTDOR-amended soils with respect to the control (0.316, 0.165 and 0.265, respectively, vs. 0.011). The overall microbial activity was stimulated by the amendments as indicated by the higher activity levels of both dehydrogenase and fluorescein diacetate hydrolase. These results indicate that DOR at the application level examined is not toxic on soil microorganisms. L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.com

Dry olive mill residue (DOR), the by-product of the two-phase extraction process, is very rich in organic matter and nutritionally relevant cations. For this reason, the agronomic use of this waste has been suggested although DOR exhibits significant phytotoxicity. The objective of this study was to investigate the impact of Paecilomyces farinosus on both organic matter modification and detoxification of this waste.Humification ratio in DOR colonized by the fungus for 20 weeks was increased by about 65% with respect to the abiotic control and humification index reached 0.38, a value that characterizes well-humified materials. High performance size-exclusion chromatography of humic acids from fungal cultures showed a marked increase in both weight-averaged and number-averaged molecular weights with respect to abiotic controls. Water-soluble phenols were reduced by 45% in 20-week-old P. farinosus cultures on DOR and mass-balance ultra-filtration showed that the relative abundance of the molecular weight fraction of phenols above 30 kDa increased from 31 to 72% suggesting the occurrence of polymerization.Experiments performed with alfalfa grown on soils containing 2.5% (w/w) of abiotic controls and fungaltreated DOR showed that phytotoxicity was totally suppressed in the waste that underwent fungal treatment. L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com

Penicillium variabile P16 is characterized by the ability to release high levels of glucose oxidase when grown in glucose-rich media converting, at the same time, glucose into gluconic acid. This work reports on gluconic acid production by the above strain grown in bench-top reactor under different strategies, traditional batch and fed-batch processes; Na2CO3 was substituted for CaCO3 as the buffering agent in order to prevent calcium gluconate precipitation over the mycelium that would limit oxygen uptake and, as a consequence, glucose conversion. Best results were obtained with an improved fed-batch process which, in addition to glucose, was continuously fed with nitrogen and minerals at a flow rate of 0.02 ml min−1: yield and total productivity were 99.4% and 2.02 g h−1, respectively, and remained constant till the end of the fermentation (240 h).

In this work the production of an extra-cellular β-glucan by Botryosphaeria rhodina DABAC P82, previously studied in a conventional bench-top stirred bioreactor, was enhanced by resorting to two different strategies consisting of dispersing different volumetric fractions of paraffin oil into the culture broth or replacing the six flat-blade Rushton turbines with 45° pitched four-blade open style (fan) turbines with different impeller-to-vessel diameter ratios (D/T). Use of fan turbines with D/T = 0.54 at a tip impeller speed of 1.4 m s−1 resulted in less viscous culture broths and most advantageous values of the β-glucan concentration (18.7 ± 0.3 kg m−3), and yield coefficients for β-glucan on mycelial biomass formed (5.1 ± 0.8 g g−1) and specific power consumed (23.3 ± 0.4 g W−1).

Bioavailability of pollutants in contaminated soils represents an important factor influencing the bioremediation process. We investigated the impact of the bioavailability of polycyclic aromatic hydrocarbons (PAHs) on the efficacy of mycoremediation of aged matrices. Two historically contaminated soils, differing in both overall PAH concentrations (2320 vs. 612 mg PAHs kg - 1 ) and in the relative amount of the non-bioavailable fraction (4.0 vs. 32%, respectively), were incubated with two white rot fungi – Irpex lacteus and Pleurotus ostreatus. When relating biodegradation results with the amount of PAH bioavailable fractions estimated by sequential supercritical fluid extractions, the correlation coefficients ranged from 0.60 to 0.83. In order to assess a possible increase of the mycoremediation efficiency, four different mobilizing agents (MAs), i.e. soybean oil, Tween 20, Tween 80 and olive-mill wastewater, were added to soil prior to fungal incubations. The addition of MAs to the soil with a negligible amount of the non-bioavailable fraction had either a limited or even a negative impact on PAH degradation. The same was true also in the case of the other soil, characterized by a larger non-bioavailable fraction. Both white rot fungi under study markedly degraded PAHs in historically contaminated soils differing significantly in PAH content and the bioavailability. However, both the fungi performed better in the soil with higher pollutant bioavailability. Consequently, a preliminary determination of non-bioavailable fraction might provide a useful indication of the performance of bioremediation treatment.

Glucose oxidase (GOX) is a glycoprotein that finds wide application in food industry and clinical analysis. The gene encoding the GOX from Penicillium variabile P16 was expressed in Pichia pastoris X 33 using the methanol inducible AOX1 promoter. Among 11 transformants resistant toward high zeocin concentrations, six Mut+ strains were screened in shaken flasks and the strain X33 c9, producing 0.33 U ml−1 of heterologous GOX after 11 days of fermentation, was selected. Recombinant GOX (ca. 50 U ml−1) was produced in a 3-l fermenter under not optimized conditions, recovered and purified in order to characterize and to compare it with the native one. The GOX from P. pastoris had a molecular weight of 82 kDa. Comparison of carbohydrate moieties showed a slight over-glycosylation of the GOX from Pichia over the native enzyme (17 and 14%, respectively). pH behavior of the recombinant enzyme, in terms of both activity and stability, was similar to that of the native one; on the other hand, a certain difference was observed in optimal temperature for activity and in thermal stability. P. pastoris appears to be a good expression system for GOX production.

The present study investigated the valorization of olive-mill wastewater (OMW) by its use as a possible growth medium for the microbial production of extra-cellular lipase. To this end, strains of Geotrichum candidum (NRRL Y-552 and Y-553), Rhizopus arrhizus (NRRL 2286 and ISRIM 383), Rhizopus oryzae (NRRL 6431), Aspergillus oryzae (NRRL 1988 and 495), Aspergillus niger (NRRL 334), Candida cylindracea (NRRL Y-17506) and Penicillium citrinum (NRRL 1841 and 3754, ISRIM 118) were screened. All strains were able to grow on the undiluted OMW, producing extra-cellular lipase activity. C. cylindracea NRRL Y-17506 showed the highest lipase activity on all the typologies of OMW used. Its lipase production on OMW was markedly affected by the type of nitrogen source and was induced by the addition of olive oil. The highest activity (9.23 IU ml−1) of the yeast was obtained on OMW supplemented with NH4Cl (2.4 g l−1) and olive oil (3.0 g l−1).

The filamentous fungus Phoma herbarum CCFEE 5080 isolated from continental Antarctica soil was tested for exopolysaccharide (EPS) production. The fungus grew and produced EPS (up to13.6 g/l) on a variety of carbon sources among which sorbitol was best, particularly at the concentration of 60 g/l. EPS production was maximum when the nitrogen source was NaNO 3 (3 g/l) and the incubation temperature was 28 °C. The polysaccharide was purified by repeated precipitation in ethanol and gel filtration and characterized as a homopolymer of glucose having a molecular weight of 7.412×10 6 ; structural analysis indicated the presence of β -1,3 and β -1,6 linkages only. After repeated freezing and thawing of the fungal biomass in the presence of EPS, the mycelial growth was much higher than that observed after freezing in the absence of EPS and the difference increased with the number of freeze–thaw cycles. It is hypothesized that the adaptation of P. herbarum CCFEE 5080 to the Antarctic soil microclimatic conditions, characterized by low temperature, high thermal fluctuations and repeated freeze–thaw cycles, might be related to the EPS production ability.

A jet-loop activated sludge reactor (JLR) of 15 dm3 working volume was used for the aerobic treatment of winery wastewater (WW). The reactor was operated continuously for more than 12 months using WW from different wineries and collected in different periods of the year with CODs that ranged between 0.8 and 12.8 kg m−3. Loading rates were from 0.4 to 5.9 kg-COD m−3 day−1 with hydraulic retention times that varied from 2.1 to 4.4 days. The system reacted well to sudden variations of loading: the COD removal efficiency was always higher than 90% with an organic load of the final effluents that ranged between 0.11 and 0.3 kg-COD m−3. After 185 days of continuous operation, the residential microbial population, of either the mixed liquor or the biofilm formed on the reactor's inner wall, was studied and characterized at the genus level. Most isolates belong to the genus Pseudomonas and the yeast Saccharomyces cerevisiae.

The production of itaconic acid from glucose-based media by Aspergillus terreus NRRL 1960 was found to be controlled by stirring rate and pH. When the phosphorous (P) level in the production medium was reduced to less than 10 mg l 1 , the fungal mycelium exhausted its primary growth and started to excrete itaconic acid, while it continued its secondary growth at the expense of ammoniacal nitrogen. The fermentation exhibited a mixed-growthassociated product formation kinetics, the non-growth associated production term (mI) being practically zero only when the pH was left free to change from 3.4 down to 1.85. On the contrary, when the pH was kept reducing up to a constant value by automatic addition of KOH 4 mol l 1 , the itaconate yield coefficient on the initial glucose supplied (YI:So) and mI and were 0.53 g g 1 and 0.028 h 1 at pH 2.4 and 320 rev min 1 and 0.5 g g 1 and 0.036 h 1 at pH 2.8 and 400 rev min 1 , respectively. Although the differences between mI and YI:So were statistically insignificant at the 95% confidence level, the net difference in the corresponding yield coefficients for itaconic acid on mycelial biomass resulted in a maximum itaconate production rate of 0.41 g l 1 h 1 at pH 2.8 and 400 rev min 1 , thus showing that this operating condition is no doubt optimal for the process under study. © 2000 Elsevier Science B.V. All rights reserved.

COD (chemical oxygen demand) removal rate and efficiency of winery wastewater (WW) aerobic treatments were evaluated in an air-bubble column bioreactor using self-adapted microbial populations either free or immobilized on polyurethane particles and in a packed-bed bioreactor immobilized on Raschig rings. The bioreactors were fed continuously for up to 12 months using WW of different origins and with different pollution loads (COD range, 0.8-11.0 kg.m(-3)): the maximum loading rate was approx. 8.8 kg-COD m(-3).d(-1). The highest COD removal rate (6.6 kg.m(-3).d(-1)) was obtained with free activated sludge in the bubble column bioreactor; treatment efficiency and hydraulic retention time were >90% and approx. 0.8 d, respectively. The microbial populations in the three reactors were characterized.

Effects of the polysaccharides alginate and locust bean gum, and oligosaccharides oligomannuronate (OM) and oligoguluronate (OG), on glucose oxidase (GOD) production by Penicillium variabile P16 were studied. Small increases were observed when the cultures were supplemented with OG and OM blocks with an average degree of polymerization (DP) of approximately ten. With 200 mg l−1 OM blocks addition at 0 h, the increase reached 32.1% compared with the control; however, regardless of the time of addition, large increases (up to approximately 70%) in GOD production were obtained with 100 and, particularly, 200 mg l−1 of alginate-derived oligosaccharides (OG and/or OM blocks) with a DP of approximately seven. No significant influence was observed on mycelial biomass.

Glucose oxidase production by the mutant M-80.10 and the parental strain of Penicillium variabile required the same nutrient addition to the production medium. Their corresponding batch cultures in a benchtop fermenter resulted in 25.6 and 19.1 U ml−1 of glucose oxidase activity, respectively, thus showing an overproduction of the mutant strain of about one third with respect to the wild type. In both strains, glucose oxidase production was not related to the autolysis phenomena, thus allowing the enzyme under study to be considered as extracellular.

Fumaric acid was produced in repeated batch processes using Rhizopus arrhizus NRRL 1526 immobilized in polyurethane sponge particles and cultivated in a fluidized-bed reactor. Fermentation conditions were established for concentration of carrier-particles and optimal concentrations of glucose nolasses (as glucose equivalent) and ammonium sulphate. Acid production was optimized (12·3 g/litre, 35·56% and 0·256 g/litre h of fumaric acid accumulation, yield and volumetric productivity of the whole process, respectively) under the following conditions: carrier-particle concentration, 20% v/v) of the working volume; glucose molasses, 50 g/litre; ammonium sulphate, alternation of cycles with 0·0 and 0·5 g/litre. The time of fermentation was 48 h per batch for a total of eight batches. Scanning electron microscopy revealed that the fungus began to grow within the particle cells but soon after the end of the first batch growth was essentially confined to the outer part of the polyurethane particle, where a peripheral layer of mycelium began to form.

The presence of antibiotic resistant bacteria was revealed among bacteria isolated from non carbonated mineral waters bottled in plastic (PVC) and in glass containers. Heterotrophic plate count values ranged between < 10 and 4.3 x 10(3) and between < 10 and 1.2 x 10(4) colony forming units/ml for the waters bottled in PVC and glass, respectively. The greatest resistance to a single antibiotic, 39.1% of 320 isolates from mineral waters, was found for nalidixic acid. Resistance to the other antibiotics was as follows: ampicillin (26.2%), bacitracin (19.7%), cotrimoxazole (18.7%), streptomycin (15.0%), tetracycline (14.4%), gentamycin (11.6%), chloramphenicol and rifampin (9.7%). The strains resistant to two or more antibiotics (multiple antibiotic resistant, MAR) provided 51% of the total isolates. Identification of 127 MAR strains showed that in the mineral waters gram-positive cocci dominated. The second, third and fourth group of identified MAR phenotypes were, in order to importance, gram-negative non-fermentative rods, gram-positive rods and gram-negative fermentative rods. The importance of the antibiotic resistant bacteria in mineral water is discussed.

Batch cultures of Penicillium variabile P16 were grown in a 3-1 benchtop bioreactor. Glucose oxidase and catalase production was followed while varying stirrer speed and adding buffering agents. Four hundred rev min−1 appeared to be optimum to ensure good growth and best enzyme production; above this, production was reduced. Among the different chemicals (CaCO3, NaOH, and NaOH plus CaCl2) employed to counteract the pH drop in the fermentation broth, CaCO3 gave the best results. The time course of growth, enzyme activities, and gluconate production at 400 rev min−1 and using CaCO3 as neutralizing agent is reported.

Because of the large volume and high organic load, olive vegetation waters represent a major pollutant which causes significant environmental problems. The waters contain, however, simple sugars, polysaccharides and pectins which make them a possible substrate for suitable micro-organisms. Cryptococcus albidus var. albidus IMAT-4735 was capable of growing on suitably treated vegetation waters, producing pectic enzyme. Enzyme production was favoured by increasing concentrations of sunflower calathide meal in the medium. On the basis of preliminary tests, the enzyme was characterized as an endopolygalacturonase with considerable potential technological interest.