Substrate Particle Size Research Articles

Incidence of Pododermatitis in Broiler Reared under Two Types of Environment

Housing environment is essential to achieve good broiler performance and to prevent diseases, including footpad dermatitis (FPD). The objective of this study was to determine the incidence of footpad dermatitis in broilers chickens according to housing type. The study was carried out with broilers reared for 5, 12, 19, 29 and 40 days. Four houses were used in this observational study. House 1 (A1) had positive pressure and reused litter; house 2 (A2) had positive pressure and new litter (sawdust); house 3 (A3) had positive pressure and new litter (rice husks); and house 4 (A4) had negative pressure and reused litter. During the entire experiment, air environmental and litter surface temperatures, and litter compaction were recorded. Pododermatitis was assessed by visual scoring of the footpads. Footpads were scored as function of the severity of the lesion. The comparison of means by the test of Bonferroni at 95% confidence interval showed higher incidence of footpad dermatitis in A3, probably due to the particle size of litter substrate. The lowest footpad dermatitis incidence was found in A1, with reused sawdust litter.

Influences of Substrate Adhesion and Particle Size on the Shape Memory Effect of Polystyrene Particles.

Formulations and applications of micro- and nanoscale polymer particles have proliferated rapidly in recent years, yet knowledge of their mechanical behavior has not grown accordingly. In this study, we examine the ways that compressive strain, substrate surface energy, and particle size influence the shape memory cycle of polystyrene particles. Using nanoimprint lithography, differently sized particles are programmed into highly deformed, temporary shapes in contact with substrates of differing surface energies. Atomic force microscopy is used to obtain in situ measurements of particle shape recovery kinetics, and scanning electron microscopy is employed to assess differences in the profiles of particles at the conclusion of the shape memory cycle. Finally, finite element models are used to investigate the growing impact of surface energies at smaller length scales. Results reveal that the influence of substrate adhesion on particle recovery is size-dependent and can become dominating at submicron length scales.

Enzymatic hydrolysis and fermentation of ultradispersed wood particles after ultrasonic pretreatment

Background: A study of the correlation between the particle size of lignocellulosic substrates and ultrasound pretreatment on the efficiency of further enzymatic hydrolysis and fermentation to ethanol. Results: The maximum concentrations of glucose and, to a lesser extent, di- and trisaccharides were obtained in a series of experiments with 48-h enzymatic hydrolysis of pine raw materials ground at 380 - 400 rpm for 30 min. The highest glucose yield was observed at the end of the hydrolysis with a cellulase dosage of 10 mg of protein (204 ± 21 units CMCase per g of sawdust). The greatest enzymatic hydrolysis efficiency was observed in a sample that combined two-stage grinding at 400 rpm with ultrasonic treatment for 5 - 10 min at a power of 10 W per kg of sawdust. The glucose yield in this case (35.5 g glucose l -1 ) increased twofold compared to ground substrate without further preparation. Conclusions: using a mechanical two-stage grinding of lignocellulosic raw materials with ultrasonication increases the efficiency of subsequent enzymatic hydrolysis and fermentation.

Riparian vegetation and sediment gradients determine invertebrate diversity in streams draining an agricultural landscape

Separation of natural and anthropogenic influences is required to identify land-use impacts on stream ecosystems. We investigated the effects of water quality and riparian condition on invertebrate assemblages along streams draining agricultural land by partitioning out changes in geomorphological characteristics. There was a strong negative relationship between invertebrate richness and distance downstream, driven by a gradient of reducing stream power and substratum particle size along the streams. When substratum particle size was accounted for, richness was reduced by ∼24% when there was limited availability of coarse particulate organic matter, resulting from lower riparian forest cover upstream. High concentrations of fertilizer-derived nitrate boosted invertebrate abundances, but only in mid sections of streams, where coarse substrata (>100mm) and high insolation were available. Sampling of multiple sites along streams facilitated partitioning of land-use impacts from natural gradients. Invertebrate richness was a good indicator of stream biophysical condition (e.g. nature of the substratum, riparian condition) at the stream scale irrespective of taxonomic resolution (family or higher) or sample size (down to 50 individuals per site), and was therefore a useful monitoring tool. The finding that riparian vegetation is a key determinant of invertebrate diversity should encourage catchment-scale maintenance and rehabilitation of native riparian forest.

Hands-on Experiments on Predatory Behaviour with Antlion Larvae

One of the innovations in the Slovenian school system has been the introduction of elective subjects in the curricula of primary and secondary schools, thus there is a lack of teaching manuals for practical exercises and hands-on classroom experience. This situation is reflected in the Ethology classroom and for that purpose we prepared step-by-step model experiments, which can be used in Ethology classes. The larvae of antlions (Myrmeleontidae) are proposed as ideal organisms for studying the effect of environmental factors on predatory behaviour. The students perform three different experiments, where the effect of substrate particle size and feeding regime on the behaviour of antlion larvae are tested. Students are made to work in three groups, and depending on the result of the first experiment, the other two experiments are performed. Students are encouraged to think about the setting, active research, thorough observation and interpretation of the data to yield meaningful information. The exercise plan is the basic principle of studying animal behaviour, and the main focus is for students to be actively involved.

Review of solid state fermentation for lignocellulolytic enzyme production: challenges for environmental applications

Within the context of increasing environmental concern, energy production from lignocellulosic substrates is gaining great interest. Enzymes have proven their efficiency in the degradation of the lignocellulosic complex but their use remains limited in environmental applications such as anaerobic digestion mainly due to their prohibitive cost. Therefore, solid state fermentation (SSF) emerges as an interesting alternative for the in situ production of lignocellulolytic enzymes. Various research efforts on the lab scale optimization of SSF are discussed. They are presented according to the type of inoculum used in the process: bacterial species and fungal species under both mesophilic and thermophilic conditions. In general, parameters that impact the SSF process include: substrate type and particle size, substrate pretreatment, inoculum, nutrient supplementation, moisture content, pH, aeration, temperature and mixing. Using different substrates, authors aim at maximizing enzyme production taking into account one to several of the indicated operational parameters. The reviewed research puts forward the adaptation of the operational parameters, enzyme production cost and loading, enzyme mixture quality and efficiency and finally reactor design as the main challenges for environmental large-scale application.

Redox stratification drives enhanced growth in a deposit-feeding invertebrate: implications for aquaculture bioremediation

Effective and affordable treatment of waste solids is a key sustainability challenge for the aquaculture industry. Here, we investigated the potential for a deposit-feeding sea cucumber, Holothuria scabra, to provide a remediation service whilst concurrently yielding a high-value secondary product in a land-based recirculating aquaculture system (RAS). The effect of sediment depth, particle size and redox regime were examined in relation to changes in the behaviour, growth and biochemical composition of juvenile sea cucumbers cultured for 81 d in manipulated sediment systems, describing either fully oxic or stratified (oxic-anoxic) redox regimes. The redox regime was the principal factor affecting growth, biochemical composition and behaviour, while substrate depth and particle size did not significantly affect growth rate or biomass production. Animals cultured under fully oxic conditions exhibited negative growth and had higher lipid and carbohydrate contents, potentially due to compensatory feeding in response to higher microphytobenthic production. In contrast, animals in the stratified treatments spent more time feeding, generated faster growth and produced significantly higher biomass yields (626.89 ± 35.44 g m-2 versus 449.22 ± 14.24 g m-2; mean ± SE). Further, unlike in oxic treatments, growth in the stratified treatments did not reach maximum biomass carrying capacity, indicating that stratified sediment is more suitable for culturing sea cucumbers. However, the stratified sediments may exhibit reduced bioremediation ability relative to the oxic sediment, signifying a trade-off between remediation efficiency and exploitable biomass yield.

Interaction between chitosan-based clay nanocomposites and cellulose in a chemical pulp suspension

Quaternized chitosan/organic montmorillonite (QCS/OMMT) nanocomposites were synthesized under microwave irradiation. XRD and TEM analyses confirmed that QCS intercalated into the interlayer of OMMT and clay layers distributed uniformly in QCS matrix. QCS/OMMT nanocomposites were used as retention and drainage-aid agents in pulp suspension, during which the interface behavior of positively charged QCS/OMMT nanocomposites on negatively charged cellulosic substrate and CaCO3 substrate was investigated. With the addition of QCS/OMMT nanocomposites, the particle size of cellulosic substrate increased, while the beating degree and the total residual carbohydrate concentration decreased. The results indicated that QCS/OMMT nanocomposite made a difference in paper making process through the charge patch interaction. Moreover, QCS/OMMT nanocomposites had a strong interaction with CaCO3, which was significant in fiber fines retention and paper production. When the mass ratio of QCS to OMMT was 8:1, the QCS/OMMT nanocomposite demonstrated the strongest retention and drainage-aid effect.

Using Redd Attributes, Fry Density, and Otolith Microchemistry to Distinguish the Presence of Steelhead and Rainbow Trout in the Elwha River Dam Removal Project

AbstractThe removal of impassable dams can affect stream fish communities in many ways, including allowing previously separated anadromous and resident life history types to intermingle. Recolonization of steelheadOncorhynchus mykiss(anadromous Rainbow Trout) into areas that were previously occupied solely by resident conspecifics presents a challenge for monitoring because (1) staging or spawning adults may be difficult to directly observe; and (2) the offspring of the two life history forms are indistinguishable during early life. We evaluated the utility of using redd attributes, fry (age‐0) size, and fry density to distinguish the presence of steelhead and Rainbow Trout in the Elwha River, Washington. Redd area and substrate size differed between forms: steelhead redds were significantly larger and had a greater median substrate particle size than Rainbow Trout redds. Fry density was significantly higher in steelhead spawning reaches than in Rainbow Trout reaches during both survey years (2010 and 2011). Steelhead fry tended to be slightly larger than Rainbow Trout fry but not significantly so in either year. Additionally, otolith microchemical analyses indicated that all fry collected from newly colonized habitat were of steelhead maternal origin, and these fish were intermediate in size to the steelhead and Rainbow Trout fry collected prior to dam removal. Thus, fry size may not effectively differentiate parental origin despite the tendency of anadromous parents to be larger and to spawn earlier than residents. Redd attributes and fry density may be useful for evaluating the spatial distributions and relative abundances of steelhead and Rainbow Trout after dam removal. Our results have implications for other dam removal projects and other monitored species.Received April 13, 2015; accepted July 3, 2015

Is Carbon Black a Suitable Model Colloidal Substrate for Diesel Soot?

Soot formation in diesel engines is known to cause premature engine wear. Unfortunately, genuine diesel soot is expensive to generate, so carbon blacks are often used as diesel soot mimics. Herein, the suitability of a commercial carbon black (Regal 250R) as a surrogate for diesel soot dispersed in engine base oil is examined in the presence of two commonly used polymeric lubricant additives. The particle size, morphology, and surface composition of both substrates are assessed using BET surface area analysis, TEM, and XPS. The extent of adsorption of a poly(ethylene-co-propylene) (dOCP) statistical copolymer or a polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) diblock copolymer onto carbon black or diesel soot from n-dodecane is compared indirectly using a supernatant depletion assay technique via UV spectroscopy. Thermogravimetric analysis is also used to directly determine the extent of copolymer adsorption. Degrees of dispersion are examined using optical microscopy, TEM, and analytical centrifugation. SAXS studies reveal some structural differences between carbon black and diesel soot particles. The mean radius of gyration determined for the latter is significantly smaller than that calculated for the former, and in the absence of any copolymer, diesel soot suspended in n-dodecane forms relatively loose mass fractals compared to carbon black. SAXS provides evidence for copolymer adsorption and indicates that addition of either copolymer transforms the initially compact agglomerates into relatively loose aggregates. Addition of dOCP or PS-PEP does not significantly affect the structure of the carbon black primary particles, with similar results being observed for diesel soot. In favorable cases, remarkably similar data can be obtained for carbon black and diesel soot when using dOCP and PS-PEP as copolymer dispersants. However, it is not difficult to identify simple copolymer-particle-solvent combinations for which substantial differences can be observed. Such observations are most likely the result of dissimilar surface chemistries, which can profoundly affect the colloidal stability.

Effect of moisture on pretreatment efficiency for anaerobic digestion of lignocellulosic substrates

The present study evaluates the effect of moisture in low-temperature and ultrasound pretreatment on lignocellulosic substrates anaerobic biodegradability, where brewer’s spent grain was used as model substrate. Besides moisture content, low-temperature pretreatment was also evaluated in terms of temperature (60–80°C) and exposure time (12–72h). Likewise, ultrasonication was also evaluated in terms of specific energy (1000–50,000kJkgTS−1). In addition, the effect of substrate particle size reduction by milling pretreatment was also considered. The results clearly demonstrated that substrate moisture (total solid concentration) is a significant parameter for pretreatment performance, although it has been rarely considered in pretreatment optimisation. Specifically, moisture optimisation increased the methane yield of brewer’s spent grain by 6% for low-temperature pretreatment (60°C), and by 14% for ultrasound pretreatment (1000kJkgTS−1) towards the control (without pretreatment). In both pretreatments, the experimental optimum total solid concentration was 100gTSkg−1. Thus, lowering substrate moisture, a strategy suggested attaining energetic pretreatment feasibility, needs to be analysed as another pretreatment variable since it might have limited correlation. Finally, a preliminary energetic balance of the pretreatments under study showed that the extra methane production could not cover the energetic pretreatment expenses.

Preference of antlion and wormlion larvae (Neuroptera: Myrmeleontidae; Diptera: Vermileonidae) for substrates according to substrate particle sizes

Sand-dwelling wormlion and antlion larvae are predators with a highly specialized hunting strategy, which either construct efficient pitfall traps or bury themselves in the sand ambushing prey on the surface. We studied the role substrate particle size plays in these specialized predators. Working with thirteen species of antlions and one species of wormlion, we quantified the substrate particle size in which the species were naturally found. Based on these particle sizes, four substrate types were established: fine substrates, fine to medium substrates, medium substrates, and coarse substrates. Larvae preferring the fine substrates were the wormlion Lampromyia and the antlion Myrmeleon hyalinus originating from desert habitats. Larvae preferring fine to medium and medium substrates belonged to antlion genera Cueta, Euroleon, Myrmeleon, Nophis and Synclisis and antlion larvae preferring coarse substrates were in the genera Distoleon and Neuroleon. In addition to analyzing naturally-occurring substrate, we hypothesized that these insect larvae will prefer the substrate type that they are found in. Specifically, we tested substrate preference in a choice experiment for four species of antlions. This was then compared to the substrate that the larvae were naturally found in. Larvae of the four antlion species were allowed to choose among eight substrates differing according to their particle size. Our findings show that the majority of M. hyalinus larvae built pits in the finest sand fraction, and the majority of N. microstenus larvae were found in a coarser fraction. The other two species, M. immaculatus and E. nostras, constructed majority of their pits in a medium sand fraction. These results support the hypothesis that neuropteran larvae prefer specific substrates for pitbuilding or ambushing prey, and that this - in combination with other abiotic and biotic factors - may drive selection of appropriate habitats.

Macroinvertebrate identity, not diversity, differed across patches differing in substrate particle size and leaf litter packs in low order, tropical Atlantic forest streams

Mac roinvertebrate identity, not diversity, differed across patches differing in substrate particle size and leaf litter packs in low order, tropical Atlantic forest streams The size of streambed sediment particles is an important determinant of habitat complexity for stream-dwelling invertebrates. In tropical streams we tested if, at the patch scale, sandy substrates were poorer in organisms and taxa when compared with larger grain-size substrates in three experiments: (a) sampling patches with coarse and fine substrates and leaf packs in eight low-order streams, (b) manipulating substrate size at the patch scale in a low-order stream and (c) sampling coarse and fine sediment patches in a larger river. We also investigated the abundance of aquatic hyphomycete conidia in these streams to relate shredder abundance with the presence of fungal decomposers, given that tropical streams are frequently reported as being poor in shredders. In the three experiments, there were consistently no differences in terms of the family richness or total number of invertebrates across the substrate types, but taxa identity differed across substrates. Invertebrate numbers and taxa were positively correlated with current velocity. Macroinvertebrate densities (150-300 individuals/m 2 ) were lower than those reported in the literature (500->1500 individuals/m 2 ), but the number of taxa was high (37 families observed, 52 estimated). Shredders comprised 13% of all individuals and 11% of all taxa. The low number of shredders contrasted with the presence of aquatic hyphomycete spores in stream waters and in leaves sampled from the streams. We concluded that the high number of taxa and low number of individuals buffer changes in substrate, allowing the presence of invertebrates even in the less-favorable substrates (sand). Although litter and aquatic hyphomycetes were present in these streams, shredders were poorly represented; this raises the question as to why litter consumers are scarce when resources are abundant in forested tropical streams.

Macroinvertebrate responses to distinct hydrological patterns in a tropical regulated river

AbstractDespite the fundamental importance of reservoirs and dams for socioeconomic development, their presence results in large‐scale alterations to the natural flow regime of the rivers and profoundly influences aquatic processes and biodiversity. This study compared macroinvertebrate community composition and structure metrics, as well as biological and ecological traits to evaluate their dependence on inter‐seasonal and intra‐seasonal flows and water quality downstream of the Itutinga reservoir situated on Rio Grande in Brazil. The results demonstrated the utility of benthic macroinvertebrate abundance, density, richness, size, reproduction, locomotion and feeding modes to assess flow regime and water quality variability. Changes in the macroinvertebrate communities were closely associated with seasonal differences in parameters such as temperature, turbidity and nutrients, which were modulated by substrate particle size and heterogeneity. Modification of the flow regime, as a result of river regulation, influences the composition, structure and functioning of river ecosystems and is reflected in changes to the aquatic communities they support. The results of this study highlight the extreme complexity of the links between physicochemical, hydrological and biological processes in lotic systems and the need to better understand these links in order to develop and implement optimal environmental flow regimes in regulated rivers. Copyright © 2015 John Wiley & Sons, Ltd.

Prediction of sugar yields during hydrolysis of lignocellulosic biomass using artificial neural network modeling

The present investigation was carried out to study application of ANN as a tool for predicting sugar yields of pretreated biomass during hydrolysis process at various time intervals. Since it is known that biomass loading and particle size influences the rheology and mass transfer during hydrolysis process, these two parameters were chosen for investigating the efficiency of hydrolysis. Alkali pretreated rice straw was used as the model feedstock in this study and biomass loadings were varied from 10% to 18%. Substrate particle sizes used were <0.5mm, 0.5–1mm, >1mm and mixed size. Effectiveness of hydrolysis was strongly influenced by biomass loadings, whereas particle size did not have any significant impact on sugar yield. Higher biomass loadings resulted in higher sugar concentration in the hydrolysates. Optimum hydrolysis conditions predicted were 10FPU/g cellulase, 5IU/g BGL, 7500U/g xylanase, 18% biomass loading and mixed particle size with reaction time between 12–28h.

Three-phasic fermentation systems for enzyme production with sugarcane bagasse in stirred tank bioreactors: Effects of operational variables and cultivation method

The high cost of enzymes is one of the main bottlenecks affecting the industrial production of cellulosic ethanol, which therefore requires the development of improved bioprocesses for the manufacture of cellulases. The present work concerns the selection of operating parameters for enzyme production in three-phasic bioreactors, using sugarcane bagasse as substrate. The parameters considered included cultivation method, substrate particle size and pretreatment, agitation speed, and pH. For both shake flask and stirred tank bioreactor (STB), a new sequential cultivation method employing steam explosion pretreated sugarcane bagasse significantly improved enzyme production, compared to conventional submerged fermentation. Larger substrate particle size provided a better support for fungal growth in shake flasks, while smaller particles resulted in greater homogeneity in stirred tank bioreactors. Maximum endoglucanase and xylanase production in the STB were 1599±66 and 4212±133IUL−1, respectively, under sequential cultivation using pretreated bagasse particles smaller than 0.5mm, agitation speed of 700rpm, and pH 5.0. The findings provide useful information concerning the influence of operational variables on (hemi) cellulases production in STB three-phasic cultivations, which should contribute to the development of bioprocesses using lignocellulosic materials in large-scale bioreactors.

Design-of-experiment strategy for the production of mannanase biocatalysts using plam karnel cake and its application to degrade locust bean and guar gum

Production of β-mannanase from thermotolerant Aspergillus terreus FBCC 1369 was optimized by response surface methodology (RSM) using plam kernel cake (PKC) as substrate. Effect of particle size of substrate, pH, moisture content and carbon and nitrogen supplements was studied. Under unoptimized conditions i.e. 2 mm particle size of PKC, moisture level 1:1 and pH 6.5 fungus produced only 41 U/gds. Initial optimum conditions i.e. 0.5 particle size of PKC, locust bean gum (1% w/v) and urea (1% w/v) at pH 6.5 and moisture level 1:1 resulted in 159 U/gds of β-mannanase yield. The effect of pH and moisture content on production was further optimized using RSM. Rotatable central composite design (RCCD) was employed to investigate the effects of pH (4–10) and moisture content (5–20 ml) on mannanase yield during solid state fermentation (SSF). Results revealed statistical significance of model as evidenced from high value of coefficient of determination (R2=1.000) and P<0.05. Optimized medium consisted of 5 g PKC of 0.5 particle size, LBG 1% (w/v) and urea 1% (w/v) as carbon and nitrogen supplementation with 12.8 ml moisture content and pH 8.0 resulting in 417 U/gds β-mannanase, which was 10- fold higher than the original value. The β-mannanase production obtained in this study using A. terreus was significantly higher than those reported in the literature. Activity of accessory enzymes, α-galactosidase (13 U/gds) and β-glucosidase (21 U/gds) in this preparation indicated that it can be used to achieve complete hydrolysis of galactoglucomannan by synergistic action of these enzymes. The end product analysis of mannanolytic action analyzed using HPLC revealed formation of mannose and mannobiose from galactomannan (locust bean and guar gum).

Dynamics of Invertebrate Diversity in a Tropical Stream

Regional studies of biotic communities are important for characterising their normal spatial and temporal variation, but there are few such studies of tropical streams. This paper describes changes in invertebrate communities in Yuccabine Creek, a seasonal upland rainforest stream in tropical Australia, over three-year and decadal periods. Invertebrate abundance, richness and evenness were temporally stable, except after major drying or wet-season flows, from which they recovered quickly; however, three wet seasons contrasted in abundance patterns. Species’ responses to flood or drought varied depending on life-histories and habitat dynamics. Communities showed contrasts between wet, early-dry and late-dry seasons, with different characteristic species. Current velocity, leaf litter and substratum particle size were the main environmental correlates with species abundances and multivariate scores. Between-decade contrasts were due to antecedent rainfall and loss of canopy cover. Trophic composition varied seasonally, driven by abundances of predators and detritivores. Yuccabine Creek differs from comparable temperate streams in its high diversity of invertebrates, continual recruitment and spring-dominated continual leaf fall; and from some other tropical streams in its seasonal flow regime. Interpretation of invertebrate metrics in these streams needs to account for historical, antecedent and current conditions, but biannual samples would adequately characterise the fauna.

Production and evaluation of antimycotic and antihepatitis C virus potential of fusant MERV6270 derived from mangrove endophytic fungi using novel substrates of agroindustrial wastes.

Among forty endophytic fungal isolates derived from the mangrove plant Avicennia marina, thirty-seven isolates (92.5 %) shown vary antimycotic activity against clinical Trichophyton, Microsporum, and Epidermophyton isolates. The hyperactive wild antagonistic strains Acremonium sp. MERV1 and Chaetomium sp. MERV7 were subjected to intergeneric protoplast fusion technique, and out of 20 fusants obtained, the fusant MERV6270 showed the highest antimycotic activity with the broadest spectrum against all dermatophytes under study. Solid-state fermentation (SSF) showed its superiority for antimycotic/antiviral metabolite production using cost-effective agroindustrial residues. Low-cost novel fermentation medium containing inexpensive substrate mixture of molokhia stalk, lemon peel, pomegranate peel, peanut peel (2:1:1:1) moistened with potato, and meat processing wastewaters (2:1, at moisture content of 60 %) provided a high antimycotic metabolite yield, 33.25 mg/gds, by the fusant MERV6270. The optimal parameters for antimycotic productivity under SSF were incubation period (4 days), incubation temperature (27.5-30 °C), initial pH (6), initial moisture level (60 %), substrate particle size (1.0 mm), and inoculum size (2 × 10(6) spores/gds), which elucidated antimycotic activity to 44.19 mg/gds. Interestingly, wild mangrove Acremonium sp. MERV1 and Chaetomium sp. MERV7 strains and their fusant MERV6270 showed significant inhibition of hepatitis C virus with viral knockdown percent of -82.48, -82.44, and -97.37 %, respectively, compared to the control (100 %), which open a new era in combat epidemic viral diseases.

Rich bioactive phenolic extract production by microbial biotransformation of Brazilian Citrus residues

Flavanones in Citrus are molecules that play an important role in antioxidant activities in nutraceutical products. Recent studies indicate that molecules of the simplest classes of phenolics have higher biological activity and absorption capacity. However, the molecules that have been shown to be very important bioactive compounds of Citrus, such as hesperetin, naringenin and ellagic acid, are found in trace concentrations in the fruit. An interesting environmentally friendly alternative that deserves attention regarding phenolic compound obtaining is the biotransformation of these molecules. The aim of this study was to develop a process of biotransformation of phenolics from Brazilian Citrus residues by solid-state fermentation with the microorganism Paecilomyces variotii. The optimized fermentation conditions were 10g of Citrus residues (2.0mm of substrate particle size), 20mL distilled water, at 32°C after 48h of incubation. The development of this process has generated, simultaneously, an increase of 900, 1400 and 1330% of hesperetin, naringenin and ellagic acid concentration, respectively, and an increase of 73% of the antioxidant capacity. These results give strong evidence that microbial biotransformation does not only produce phenolic compounds but also compounds with high biological activity, such as hesperetin and naringenin.