Self-Rated Masculinity and Femininity and Reported Number of Lifetime Sexual Partners Among Cisgender Heterosexual and LGBQ Men and Women.

Prior research has quantitatively examined why heterosexual men and women report different numbers of lifetime different-sex sexual partners, whereas qualitative work has analyzed how men's masculinity-and to a lesser extent, women's femininity-is tied to gender norms about sexual activity. Less research, however, has quantitatively examined the associations between self-rated masculinity and femininity and reported number of lifetime sexual partners. This brief report uses a large sample of Canadians (n = 2117) to examine how self-rated masculinity and femininity relate to reported numbers of sexual partners among four groups of cisgender people: (1) heterosexual men (n = 972), (2) heterosexual women (n = 979), (3) gay and bisexual/pansexual men (n = 99), and (4) lesbian and bisexual/pansexual women (n = 67). Results demonstrate that self-rated femininity was negatively, and masculinity positively, associated with reported numbers of lifetime different-sex sexual partners among heterosexual women. No significant associations emerged for other groups. The lack of significant associations among heterosexual men may be attributable to the fact that most rated themselves as very masculine and not very feminine, whereas there was more variation among heterosexual women. In contrast, the non-significance among LGBQ women and men could reflect that subcultural norms and practices more strongly shape the number of sexual partners individuals report having in these communities. These results demonstrate that it would be beneficial for researchers to measure self-rated masculinity and femininity in future studies about sexual partnering practices, especially among heterosexual cisgender women.

Men's Feminist Identification and Reported Use of Prescription Erectile Dysfunction Medication.

We analyzed data from the 2018 Sex in Canada survey (n = 1,015 cisgender men) to examine the association between feminist identification and reported use of prescription ED medication (EDM) during men's last sexual encounter. Feminist-identified men were substantially more likely to report EDM use than non-feminist men, even after controlling for alcohol use before sex, erection difficulties, sexual arousal, sexual health, mental health, and physical health. One explanation is that feminist men may use EDM to bolster their masculinity when it is otherwise threatened by their identification as feminist. Another is that non-feminist men may be less likely to use prescription EDM because they view accessing healthcare services as a threat to their masculinity. It is also possible that feminist men are more likely to use EDM because they wish to maintain an erection to better please their partner. Lastly, feminist men may be more honest about EDM use than non-feminist men, even though rates are similar. Regardless of the exact reason, therapists can use these results to tailor sexual health messages to clients based on feminist identification. Future work could employ qualitative methods to understand why feminist men report higher rates of EDM use than non-feminist men.

Subcultural Identification, Penetration Practices, Masculinity, and Gender Labels within a Nationally Representative Sample of Three Cohorts of American Black, White, and Latina/o LGBQ People.

Most quantitative research about lesbian, gay, bisexual, and queer (LGBQ) people's sexual subcultures and sexual practices has used non-probability samples due to data limitations. This paper used the Generations study, a national probability sample of LGBQ Americans in three age cohorts, 18-25 (n = 510), 34-41 (n = 294), and 52-59 (n = 425), who also identified as Black, white, or Latina/o. This paper analyzed men (n = 590) and women (n = 639) to answer the following sets of research questions: (1) What is the prevalence of subcultural identification as bear, leather/kink, twink, and jock among men, and how does it differ by cohort, race/ethnicity, and sexual identity? (2) What is the prevalence of men who describe themselves as a top, versatile top, versatile, versatile bottom, and bottom? What is the relationship between penetration practices and masculinity? (3) What is the prevalence of gender labels among women as femme, androgynous, and butch? How does the prevalence differ by cohort, race/ethnicity, and sexual identity? (4) What is the relationship between women's gender labels and masculinity? Penetration practices were fairly evenly distributed among men, and there were few differences in masculinity based on penetration practices after controlling for demographics and subcultural identification. Most women did not use gender labels, but butch identities were more common among lesbians and femme labels were more common among Black women and Latinas.

Heterosexual Identification and Same-Sex Partnering: Prevalence and Attitudinal Characteristics in the USA.

This paper used the 2011-2017 National Survey of Family Growth to estimate population sizes and attitudinal characteristics of heterosexual-identified men who have sex with men (MSM) and women who have sex with women (WSW) aged 15-44 years. Analyses estimated population sizes in stages: after excluding respondents who reported only one lifetime same-sex partner, which happened before the age of 15; after excluding males who reported nonconsensual male-male sex; after excluding respondents who reported only one lifetime same-sex partner, regardless of the age at which that experience occurred; after excluding respondents who reported only two lifetime same-sex partners, the first of which occurred before age 15; and after excluding males who reported male-male sex work. The broadest criteria included many individuals with limited same-sex sexual histories or those who experienced nonconsensual sex or potentially coerced sex in youth. After excluding those respondents, analyses showed that heterosexual-identified MSM and WSW had a diversity of attitudes about gender and LGB rights; only a distinct minority were overtly homophobic and conservative. Researchers should carefully consider whether to include respondents who report unwanted sexual contact or sex at very young ages when they analyze sexual identity-behavior discordance or define sexual minority populations on the basis of behavior.

Sexual Identity-Behavior Discordance in Canada.

This paper uses two surveys to examine sexual identity-behavior discordance in Canada. The first is the Sex in Canada survey (SCS), which is a private survey of 2,303 Canadians. The second is the 2015-2016 Canadian Community Health Survey (CCHS), which is a large nationally representative government-administered survey with 109,659 respondents. Results from the CCHS show that identity-behavior discordance and overall rates of same-sex contact are lower in Canada than in the US, UK, or Australia. An estimated .7 percent of males and 2.7 percent of females aged 15-64 who had had lifetime sex identified as heterosexual yet have had same-sex contact, figures which equate to an estimated 65,700 males and 255,100 females. Few demographic factors were associated with discordance. Results from the SCS show that about two-thirds of heterosexuals with identity-behavior discordance were moderately supportive of LGBQ rights and one-third were moderately homophobic. Future research will need to uncover why a lower proportion of Canadians report same-sex partners and identity-behavior discordance than their counterparts in the US, UK, or Australia. Cet article utilise deux enquêtes pour examiner la discordance entre l'identité sexuelle et le comportement au Canada. La première est l'enquête Sex in Canada (SCS), qui est une enquête privée menée auprès de 2 303 Canadiens. La seconde est l'Enquête sur la santé dans les collectivités canadiennes (ESCC) de 2015-2016, qui est une grande enquête représentative à l'échelle nationale administrée par le gouvernement auprès de 109 659 répondants. Les résultats de l'ESCC montrent que la discordance identité-comportement et les taux globaux de contacts entre personnes de même sexe sont plus faibles au Canada qu'aux États-Unis, au Royaume-Uni ou en Australie. On estime que 0,7 % des hommes et 2,7 % des femmes âgés de 15 à 64 ans ayant eu des rapports sexuels au cours de leur vie se sont identifiés comme hétérosexuels, mais ont eu des contacts avec des personnes du même sexe, ce qui correspond à environ 65 700 hommes et 255 100 femmes. Peu de facteurs démographiques étaient associés à la discordance. Les résultats de l'enquête SCS montrent qu'environ deux tiers des hétérosexuels présentant une discordance entre identité et comportement étaient modérément favorables aux droits des LGBQ et qu'un tiers était modérément homophobe. Les recherches futures devront découvrir pourquoi une plus faible proportion de Canadiens déclarent avoir des partenaires de même sexe et être en désaccord avec leur identité et leur comportement que leurs homologues aux États-Unis, au Royaume-Uni ou en Australie.

New Insight into Parrots' Mitogenomes Indicates That Their Ancestor Contained a Duplicated Region.

Mitochondrial genomes of vertebrates are generally thought to evolve under strong selection for size reduction and gene order conservation. Therefore, a growing number of mitogenomes with duplicated regions changes our view on the genome evolution. Among Aves, order Psittaciformes (parrots) is especially noteworthy because of its large morphological, ecological, and taxonomical diversity, which offers an opportunity to study genome evolution in various aspects. Former analyses showed that tandem duplications comprising the control region with adjacent genes are restricted to several lineages in which the duplication occurred independently. However, using an appropriate polymerase chain reaction strategy, we demonstrate that early diverged parrot groups contain mitogenomes with the duplicated region. These findings together with mapping duplication data from other mitogenomes onto parrot phylogeny indicate that the duplication was an ancestral state for Psittaciformes. The state was inherited by main parrot groups and was lost several times in some lineages. The duplicated regions were subjected to concerted evolution with a frequency higher than the rate of speciation. The duplicated control regions may provide a selective advantage due to a more efficient initiation of replication or transcription and a larger number of replicating genomes per organelle, which may lead to a more effective energy production by mitochondria. The mitogenomic duplications were associated with phenotypic features and parrots with the duplicated region can live longer, show larger body mass as well as predispositions to a more active flight. The results have wider implications on the presence of duplications and their evolution in mitogenomes of other avian groups.

Use of Savitzky-Golay Filter for Performances Improvement of SHM Systems Based on Neural Networks and Distributed PZT Sensors.

A considerable amount of research has focused on monitoring structural damage using Structural Health Monitoring (SHM) technologies, which has had recent advances. However, it is important to note the challenges and unresolved problems that disqualify currently developed monitoring systems. One of the frontline SHM technologies, the Electromechanical Impedance (EMI) technique, has shown its potential to overcome remaining problems and challenges. Unfortunately, the recently developed neural network algorithms have not shown significant improvements in the accuracy of rate and the required processing time. In order to fill this gap in advanced neural networks used with EMI techniques, this paper proposes an enhanced and reliable strategy for improving the structural damage detection via: (1) Savitzky-Golay (SG) filter, using both first and second derivatives; (2) Probabilistic Neural Network (PNN); and, (3) Simplified Fuzzy ARTMAP Network (SFAN). Those three methods were employed to analyze the EMI data experimentally obtained from an aluminum plate containing three attached PZT (Lead Zirconate Titanate) patches. In this present study, the damage scenarios were simulated by attaching a small metallic nut at three different positions in the aluminum plate. We found that the proposed method achieves a hit rate of more than 83%, which is significantly higher than current state-of-the-art approaches. Furthermore, this approach results in an improvement of 93% when considering the best case scenario.

Correction: A new parrot taxon from the Yucatán Peninsula, Mexico-its position within genus Amazona based on morphology and molecular phylogeny.

[This corrects the article DOI: 10.7717/peerj.3475.].

A new parrot taxon from the Yucatán Peninsula, Mexico-its position within genus Amazona based on morphology and molecular phylogeny.

Parrots (Psittaciformes) are a diverse group of birds which need urgent protection. However, many taxa from this order have an unresolved status, which makes their conservation difficult. One species-rich parrot genus is Amazona, which is widely distributed in the New World. Here we describe a new Amazona form, which is endemic to the Yucatán Peninsula. This parrot is clearly separable from other Amazona species in eleven morphometric characters as well as call and behavior. The clear differences in these features imply that the parrot most likely represents a new species. In contrast to this, the phylogenetic tree based on mitochondrial markers shows that this parrot groups with strong support within A. albifrons from Central America, which would suggest that it is a subspecies of A. albifrons. However, taken together tree topology tests and morphometric analyses, we can conclude that the new parrot represents a recently evolving species, whose taxonomic status should be further confirmed. This lineage diverged from its closest relative about 120,000 years ago and was subjected to accelerated morphological and behavioral changes like some other representatives of the genus Amazona. Our phylogenies, which are so far the most comprehensive for Amazona taxa enabled us to consider the most feasible scenarios about parrot colonization of the Greater and Lesser Antilles and Central America from South America mainland. The molecular dating of these migrations and diversification rate were correlated with climatic and geological events in the last five million years, giving an interesting insight into Amazon parrot phylogeography and their evolution in general.

The functional properties of a xyloglucanase (GH12) of Aspergillus terreus expressed in Aspergillus nidulans may increase performance of biomass degradation.

Filamentous fungi are attractive hosts for heterologous protein expression due to their capacity to secrete large amounts of enzymes into the extracellular medium. Xyloglucanases, which specifically hydrolyze xyloglucan, have been recently applied in lignocellulosic biomass degradation and conversion in many other industrial processes. In this context, this work aimed to clone, express, and determine the functional properties of a recombinant xyloglucanase (AtXEG12) from Aspergillus terreus, and also its solid-state (SSF) and submerged (SmF) fermentation in bioreactors. The purified AtXEG12 showed optimum pH and temperature of 5.5 and 65 °C, respectively, demonstrating to be 90 % stable after 24 h of incubation at 50 °C. AtXEG12 activity increased in the presence of 2-mercaptoethanol (65 %) and Zn+2 (45 %), while Cu+2 and Ag+ ions drastically decreased its activity. A substrate assay showed, for the first time for this enzyme's family, xylanase activity. The enzyme exhibited high specificity for tamarind xyloglucan (K M 1.2 mg mL-1) and V max of 17.4 µmol min-1 mg-1 of protein. The capillary zone electrophoresis analysis revealed that AtXEG12 is an endo-xyloglucanase. The heterologous xyloglucanase secretion was greater than the production by wild-type A. terreus cultivated in SmF. On the other hand, AtXEG12 activity reached by SSF was sevenfold higher than values achieved by SmF, showing that the expression of recombinant enzymes can be significantly improved by cultivation under SSF.

Increased biomass saccharification by supplementation of a commercial enzyme cocktail with endo-arabinanase from Bacillus licheniformis.

OBJECTIVES: The use of endo-arabinanase from Bacillus licheniformis (ABNase) for sugarcane saccharification has been evaluated by enzyme immobilization and commercial cocktail supplement with the immobilized heterologous protein. RESULTS: Biochemical characterization of the purified ABNase showed that the catalytic activity was strongly inhibited by 5 mM Cu(2+), Zn(2+) or Fe(3+). The optimum pH and temperature for activity were 5.5-6.5 and 35-40 °C, respectively. The enzyme stability increased 128-fold when immobilized with glyoxyl agarose, and the hydrolysis of pretreated sugar cane biomass increased by 15 % when a commercial enzyme cocktail was supplemented with immobilized ABNase. CONCLUSION: Pectin hydrolysis by recombinant ABNase plays a role in the effective application of enzymatic cocktails for biomass saccharification.

Inhabiting the sexual landscape: toward an interpretive theory of the development of sexual orientation and identity.

Building on Paula Rust's (1996) concept of a sexual landscape, we propose an interpretive theory of the development of both sexual orientation and sexual identity. We seek to reconcile human agency with active and shifting influences in social context and to recognize the inherent complexity of environmental factors while acknowledging the role that biological potential plays. We ground our model in the insights of three compatible and related theoretical perspectives: social constructionism, symbolic interactionism, and scripting theory. Within this framework, we explain how sexual orientation and sexual identities develop and potentially change.

Purification and biochemical properties of multiple xylanases from Aspergillus ochraceus tolerant to Hg2+ ion and a wide range of pH.

Production of multiple xylanases, in which each enzyme has a specific characteristic, can be one strategy to achieve the effective hydrolysis of xylan. Three xylanases (xyl 1, xyl 2, and xyl 3) from Aspergillus ochraceus were purified by chromatography using diethylaminoethyl (DEAE) cellulose, Biogel P-60, and Sephadex G-100 columns. These enzymes are glycoproteins of low molecular weight with an optimum temperature at 60 °C. The glycosylation presented is apparently not related to thermostability, since xyl 3 (20 % carbohydrate) was more thermostable than xyl 2 (67 % carbohydrate). Xyl 3 was able to retain most of its activity in a wide range of pH (3.5-8.0), while xyl 1 and xyl 2 presented optimum pH of 6.0. Xyl 1 and xyl 2 were activated by 5 and 10 mM MnCl2 and CoCl2, while xyl 3 was activated by 1 mM of the same compounds. Interestingly, xyl 2 presented high tolerance toward mercury ion. Xylanases from A. ochraceus hydrolyzed xylans of different origins, such as birchwood, oat spelt, larchwood, and eucalyptus (around 90 % or more), except xyl 2 and xyl 3 that hydrolyzed with lesser efficiency eucalyptus (66.7 %) and oat spelt (44.8 %) xylans.

A novel ß-glucosidase from Humicola insolens with high potential for untreated waste paper conversion to sugars.

Humicola insolens produced a new ß-glucosidase (BglHi2) under solid-state fermentation. The purified enzyme showed apparent molecular masses of 116 kDa (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and 404 kDa (gel-filtration), suggesting that it is a homotetramer. Mass spectrometry analysis showed amino acid sequence similarity with a ß-glucosidase from Chaetomium thermophilum. Optima of pH and temperature were 5.0 and 65 °C, respectively, and the enzyme was stable for 60 min at 50 °C, maintaining 71 % residual activity after 60 min at 55 °C. BglHi2 hydrolyzed p-nitrophenyl-ß-D-glucopyranoside and cellobiose. Cellobiose hydrolysis occurred with high apparent affinity (K M = 0.24 ± 0.01 mmol L(-1)) and catalytic efficiency (k cat/K M = 1,304.92 ± 53.32 L mmol(-1) s(-1)). The activity was insensitive to Fe(+3), Cr(+2), Mn(+2), Co(+2), and Ni(2+), and 50-60 % residual activities were retained in the presence of Pb(2+), Hg(2+), and Cu(2+). Mixtures of pure BglHi2 or H. insolens crude extract (CE) with crude extracts from Trichoderma reesei fully hydrolyzed Whatman no. 1 paper. Mixtures of H. insolens CE with T. reesei CE or Celluclast 1.5 L fully hydrolyzed untreated printed office paper, napkin, and magazine papers after 24-48 h, and untreated cardboard was hydrolyzed by a H. insolens CE/T. reesei CE mixture with 100 % glucose yield. Data revealed the good potential of BglHi2 for the hydrolysis of waste papers, promising feedstocks for cellulosic ethanol production.

Increase of the phytase production by Aspergillus japonicus and its biocatalyst potential on chicken feed treatment.

Phytase hydrolyzes phytic acid from the plant components of animal feed, releasing inorganic phosphorus. The phytase production by Aspergillus japonicus was optimized using Plackett-Burman designs (PBD), composite central rotational designs (CCRD), and response surface methodology from standard Czapek medium. The enzyme was applied in broiler chicken and laying hen foods. Analysis from PBD showed that KH2 PO2, MgSO4 · 7H2O, and yeast extract had significant influences on phytase secretion (p < 0.05). The best results from the CCRD experiments were obtained using (A) 0.040% KH2 PO4, (B) 0.050% MgSO4 · 7H2O, and (C) 0.040% yeast extract, enhancing in 49-53 U mg(-1) protein. The determination coefficient (R(2)) was 0.92 and Fcalc was 7.48 times greater than Flisted . Thus, the reduced coded model: Y (U mg-1) = 50.29 + 4.30A - 3.35(A)2 - 4.80(B)2 + 5.62C - 4.26(C)2 was considered predictive and statistically significant (p < 0.05). The optimized culture medium increased the phytase yield in 250%. A. japonicus phytase released high levels of Pi from broiler chicken and laying hen food. A. japonicus is an excellent phytase producer in a culture medium using inexpensive components and agricultural wastes. Therefore, these results provide sound arguments for the formulation of a low cost culture medium for phytase production.

Co-immobilization of fungal endo-xylanase and α-L-arabinofuranosidase in glyoxyl agarose for improved hydrolysis of arabinoxylan.

Plant cell-wall arabinoxylans have a complex structure that requires the action of a pool of debranching (arabinofuranosidases) and depolymerizing enzymes (endo-xylanase). Two Aspergillus nidulans strains over-secreting endo-xylanase and arabinofuranosidase were inoculated in defined 2% maltose-minimum medium resulting in the simultaneously production of these enzymes. To study the synergistic hydrolysis was used arabinoxylan with 41% of arabinose and 59% of xylose residues. Thus, it was adopted different approaches to arabinoxylan hydrolysis using immobilized arabinofuranosidase and endo-xylanase: (i) endo-xylanase immobilized on glyoxyl agarose; (ii) arabinofuranosidase immobilized on glyoxyl agarose; (T1) hydrolysis of arabinoxylan with arabinofuranosidase immobilized on glyoxyl agarose for debranching, followed by a second hydrolysis with endo-xylanase immobilized on glyoxyl agarose; (T2) hydrolysis using (i) and (ii) simultaneously; and (T3) hydrolysis of arabinoxylan with endo-xylanase and arabinofuranosidase co-immobilized on glyoxyl agarose. It was concluded that arabinoxylan hydrolysis using two derivatives simultaneously (T2) showed greater hydrolytic efficiency and consequently a higher products yield. However, the hydrolysis with multi-enzymatic derivative (T3) results in direct release of xylose and arabinose from a complex substrate as arabinoxylan, which is a great advantage as biotechnological application of this derivative, especially regarding the application of biofuels, since these monosaccharides are readily assimilable for fermentation and ethanol production.

Functional properties of a manganese-activated exo-polygalacturonase produced by a thermotolerant fungus Aspergillus niveus.

A thermotolerant fungus identified as Aspergillus niveus was isolated from decomposing materials and it has produced excellent levels of hydrolytic enzymes that degrade plant cell walls. A. niveus germinated faster at 40 °C, presenting protein levels almost twofold higher than at 25 °C. The crude extract of the A. niveus culture was purified by diethylaminoethyl (DEAE)-cellulose, followed by Biogel P-100 column. Polygalacturonase (PG) is a glycoprotein with 37.7 % carbohydrate, molecular mass of 102.6 kDa, and isoelectric point of 5.4. The optimum temperature and pH were 50 °C and 4.0-6.5, respectively. The enzyme was stable at pH 3.0 to 9.0 for 24 h. The DEAE-cellulose derivative was about sixfold more stable at 60 °C than the free enzyme. Moreover, the monoaminoethyl-N-aminoethyl-agarose derivative was tenfold more stable than the free enzyme. PG was 232 % activated by Mn(2+). The hydrolysis product of sodium polypectate corresponded at monogalacturonic acid, which classifies the enzyme as an exo-PG. The K m, V max, K cat, and K cat/K m values were 6.7 mg/ml, 230 U/mg, 393.3/s, and 58.7 mg/ml/s, respectively. The N-terminal amino acid sequence presented 80 % identity with PglB1, PglA2, and PglA3 putative exo-PG of Aspergillus fumigatus and an exo-PG Neosartorya fischeri.

Purification, partial characterization, and covalent immobilization-stabilization of an extracellular α-amylase from Aspergillus niveus.

An extracellular amylase secreted by Aspergillus niveus was purified using DEAE fractogel ion exchange chromatography and Sephacryl S-200 gel filtration. The purified protein migrated as a single band in 5 % polyacrylamide gel electrophoresis (PAGE) and 10 % sodium dodecyl sulfate (SDS-PAGE). The enzyme exhibited 4.5 % carbohydrate content, 6.6 isoelectric point, and 60 and 52 kDa molar mass estimated by SDS-PAGE and Bio-Sil-Sec-400 gel filtration column, respectively. The amylase efficiently hydrolyzed glycogen, amylose, and amylopectin. The end-products formed after 24 h of starch hydrolysis, analyzed by thin layer chromatography, were maltose, maltotriose, maltotetraose, and maltopentaose, which classified the studied amylase as an α-amylase. Thermal stability of the α-amylase was improved by covalent immobilization on glyoxyl agarose (half-life of 169 min, at 70 °C). On the other hand, the free α-amylase showed a half-life of 20 min at the same temperature. The optima of pH and temperature were 6.0 and 65 °C for both free and immobilized forms.

A novel xylan degrading ß-D-xylosidase: purification and biochemical characterization.

Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular ß-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. ß-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 °C and 3.0-5.5, respectively. ß-xylosidase was stable in acidic pH (3.0-6.0) and 70 °C for 1 h. The enzyme was activated by 5 mM MnCl2 (28 %) and MgCl2 (20 %) salts. The ß-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-ß-D-xylopyranoside, exhibiting apparent K(m) and V(max) values of 0.66 mM and 39 U (mg protein)⁻¹ respectively, and to a lesser extent p-nitrophenyl-ß-D-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources, suggesting a novel ß-D-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by ß-xylosidase. TLC confirmed the capacity of the enzyme in hydrolyzing xylan and larger xylo-oligosaccharides, as xylopentaose.

Thermostable invertases from Paecylomyces variotii produced under submerged and solid-state fermentation using agroindustrial residues.

The filamentous fungus Paecylomices variotii was able to produce high levels of cell extract and extracellular invertases when grown under submerged fermentation (SbmF) and solid-state fermentation, using agroindustrial products or residues as substrates, mainly soy bran and wheat bran, at 40°C for 72 h and 96 h, respectively. Addition of glucose or fructose (≥1%; w/v) in SbmF inhibited enzyme production, while the addition of 1% (w/v) peptone as organic nitrogen source enhanced the production by 3.7-fold. However, 1% (w/v) (NH(4))(2)HPO(4) inhibited enzyme production around 80%. The extracellular form was purified until electrophoretic homogeneity (10.5-fold with 33% recovery) by DEAE-Fractogel and Sephacryl S-200 chromatography. The enzyme is a monomer with molecular mass of 102 kDa estimated by SDS-PAGE with carbohydrate content of 53.6%. Optima of temperature and pH for both, extracellular and cell extract invertases, were 60°C and 4.0-4.5, respectively. Both invertases were stable for 1 h at 60°C with half-lives of 10 min at 70°C. Mg(2+), Ba(2+) and Mn(2+) activated both extracellular and cell extract invertases from P. variotii. The kinetic parameters K(m) and V(max) for the purified extracellular enzyme corresponded to 2.5 mM and 481 U/mg prot(-1), respectively.