Search

Abstract Background Palatal groove represents a relatively uncommon developmental root anomaly, usually found on the palatal aspect of maxillary incisors. While its origin is controversial, its presence predisposes to severe periodontal defects. Aim This study aimed to provide a systematic review of the literature focusing on the varied diagnostic techniques and treatment modalities for periodontal lesions arising from the presence of palatal groove. Based on the existing evidence and knowledge, the study also provides a comprehensive decisional tree, guiding clinicians in the challenging decision-making process face to a palatal groove. Methods The literature search was conducted on Medline and Cochrane databases by two independent reviewers, who also performed the screening and selection process, looking for English written articles reporting on diagnosis and management (all treatment approaches) of periodontal lesion(s) associated with a palatal groove. Based on this literature, a comprehensive decisional tree, including a standardized palatal groove evaluation and tailored treatment approaches, is proposed. Moreover, a clinical case is described to demonstrate the practical application of the developed decisional tree. Results Over a total of 451 articles initially identified, 34 were selected, describing 40 patients with 40 periodontal lesions associated with palatal grooves. The case report illustrates a deep, large, circumferential intra-bony defect on the palatal side of the tooth #22 associated with a shallow, moderately long palatal groove in an 18-year-old male patient. Following reevaluation, a single flap surgery was deemed necessary, combined with a regenerative procedure. At 2 years post-treatment, the tooth #22 is healthy, in a functional and esthetic position. The decision-making process, based on local and systemic patient’s conditions, should allow an early and precise diagnosis to prevent further complications and undertake an adequate treatment. Conclusion Palatal grooves are relatively rare; however, they are frequently associated with severe periodontal defects. The identification, diagnosis, prompt, and tailored management of the associated lesion is essential to mitigate potential periodontal and endodontic complications related to the presence of palatal groove. Systematic Review Registration [ https://www.crd.york.ac.uk/prospero/ ], identifier [C CRD42022363194].

Objective: Aging is a natural process associated with a decline in cognition. However, the mediating effect of physical function and circulating myokines on this relationship has yet to be fully clarified. This study investigated how muscle strength and circulating insulin-like growth factor-1 (IGF-1) levels mediate the relationship between age and cognitive functions. Subjects and methods: A total of 1255 participants aged 25–74 years included in the Midlife in the United States II study were retrospectively analyzed. In this cross-sectional analysis, we applied a serial mediation model to explore the mediating effects of muscle strength and circulating IGF-1 levels on the relationship between age and cognitive functions. We included potential confounding factors related to sociodemographics, lifestyle, and health status as covariates in the model. Results: The results showed that aging had both direct and indirect effects on cognition. As predicted, muscle strength and IGF-1 levels mediated the relationship between age and specific cognitive functions. In addition, mediation analyses indicated that the association between aging and cognitive flexibility, immediate and delayed memory, and inductive reasoning were partially mediated by muscle strength and IGF-1 levels in a serial manner. Conclusions: Our study demonstrated the serial multiple mediation roles of muscle strength and IGF-1 levels on the relationship between age and specific cognitive functions. Further longitudinal research should be performed to confirm the serial mediation results.

L’expression « sémiotique plastique », proposée par Jean-Marie Floch, à la suite de Greimas, est déjà en soi un choix critique. Elle a permis d’éviter le piège des typologies sémiotiques précédentes, fondées sur les canaux sensoriels, car la dimension plastique n’est pas réservée au domaine visuel ! « Sémiotique plastique » implique en effet d’emblée un type de sémiose, doté de ses plans de l’expression et du contenu spécifiques : l’identification d'un plan de l’expression spécifique ne semble pas difficile, mais celle du plan du contenu est plus problématique. Le Groupe μ a consacré une bonne partie de son Traité du signe visuel (1992) à ce qu’il appelle le « signe plastique », mais autant sa description systématique de l’expression plastique semble exhaustive, cohérente et donc convaincante, autant ses propositions concernant le contenu plastique, en défaut par rapport au principe d’hétérotopie (isomorphisme gardé) entre expression et contenu, semblent un peu trop redondantes (ou dépendantes) par rapport à l’expression, et faiblement heuristiques. Précisément, le problème sous-jacent est le statut de la dimension plastique, qui a beaucoup à perdre à être spécialisée dans le visuel, et beaucoup à gagner à être considérée comme un type particulier mais transversal de sémiose (par rapport aux types d’objets, aux canaux sensoriels, et même aux domaines de connaissance). C’est pourquoi la question de la spécificité de ses contenus est décisive, mais seulement si elle est abordée dans une perspective anthropologique et culturelle générale. Il se trouve qu'à cet égard, Greimas, Floch, mais aussi Thürlemann, ont déjà mis en évidence, dans leurs analyses, des contenus plastiques qui prenaient des allures narrativo-mythiques et anthropologiques nettement hétérotopiques par rapport aux expressions plastiques. Pour préciser la dimension plastique, Jean-Marie Floch avait parfaitement identifié une partie de la difficulté — et la possibilité d’une solution — avec les systèmes semi-symboliques : les relations propres à la sémiose plastique seraient caractérisées par la corrélation entre les oppositions de l’expression plastique et les oppositions des contenus plastiques. Mais, si les systèmes semi-symboliques garantissent l’indépendance et l’hétéronomie entre expressions et contenus plastiques, ils ne disent rien sur la nature des contenus en question. Voilà pourquoi notre enquête, qualifiée d’« archéologie de la dimension plastique », s’efforce ici de parcourir les principales typologies où naissent les possibilités de contenus plastiques, qui sont, en fait, différentes propositions en matière de types de signification : celles proposées par la scolastique médiévale (quatre types de signification), celles reformulées par l’iconologie (trois types), celles avancées, enfin, par Barthes (deux ou trois types, selon les versions) et Greimas (deux types) : il en ressort précisément que la particularité des contenus plastiques ne peut être appréhendée que par une approche anthropologique et comparée.

In his play Rhinoceros, Ionesco stages the transformation of actors into rhinoceros. Only one, Bérenger, resists until the end. All those who, one after another, become rhinos and join the herd are explicitly endowed with the modalities of competence and existence: they know, they can, they want, they must and they believe. On the other hand, Bérenger is characterized by a set of sketched, degraded or neutralized modalities: he doubts everything, first of all himself, he can be weakly, he is indecisive, vaguely skeptical, and is incapable of respecting a norm, an instruction or an imposed schedule. At first glance, if we confront the modal distribution on the one hand, and the physico-ontological transformation of the actors on the other, we would be dealing with a paradoxical narrative unfolding: positive modal competence would lead to dehumanization and social and cultural collapse, while its absence, degradation or instability would lead to the affirmation of the human, of society and of culture.Faced with this paradox, several hypotheses emerge from a careful rereading of Ionesco’s text: (1) the difference between the two types of modalizations (that of the actors who become rhinoceros and that of Bérenger) does not relate mainly to the semantic and thematic content of the modalities, but to the way in which the actors assume them, state them and manifest them; (2) this assumption and these manifestations are somehow directed or determined, implicitly, by underlying valences: (i) intensity of intersubjective and emotional sensitivity and its modulations and variations, and (ii) extension of repetition, of number and of conformity to oneself and to others; (3) all of these infra- (or supra-) modal differences constitute a tonality (in fact, several tonalities), and it is this tonality that acts as a sorting operator between the actors who become rhinoceros and one who can reaffirm his humanity.This contribution will mainly aim to define, analyze and situate what is a tonality. The distinction and the articulation that we propose, between the modal and the tonal, also leads to the identification of the sensitive styles (lifestyles, styles of behavior, styles of attitudes, etc.), particularly for forms of living and modes of existence.

Populismo e populista são denominações que, ao mesmo tempo, são mal definidas – até indefiníveis – e cuja enunciação é, no entanto, eficiente. O argumen-to inicial deste estudo consiste em uma inversão dessa relação: é justamente por essa indeterminação que a enunciação é eficiente. A dificuldade de uma definição estável de populismo é uma consequência direta da transformação contemporânea do actante coletivo, ao qual chamamos povo, que é, ele próprio, hoje em dia, indeterminado, flu-tuante e heterogêneo. Um dos desdobramentos dessa situação consiste em reivindicar a denominação populista, porque essa reivindicação pública é uma legitimação tanto da existência de um actante coletivo chamado povo quanto da coerência de temas e posições políticos associados. Assim, circunscrevemos o problema a ser tratado: por um lado, atribuímos ao populismo temas e posições políticos que não lhe são específicos e, por outro, associamos o populismo a paixões tristes (desconfiança, rejeição ao outro, sofrimento, ódio, medo...). Segundo pesquisas de opinião pública, tais paixões são compartilhadas pela maioria dos cidadãos, muito além apenas daqueles que votam nos candidatos populistas. Nossa hipótese é, então, que, no caso do voto e da expressão política populistas, essas paixões chamadas tristes funcionam como atratores dos temas e posições políticos associados ao populismo.

La notion de formes de vie a été introduite par Greimas il y a très exactement 30 ans dans le champ des études sémiotiques. Depuis, cette notion est devenue un concept intégré à l’organon sémiotique, mais sa signification est restée équivoque, et ce, bien que des propositions de définitions soient apparues au fil des décennies (Fontanille, 1993 ; 2008 ; 2015 ; Perusset, 2020). Cet article vise à offrir une synthèse générale de ces travaux d’explicitation avec comme ambition de rendre la notion la plus claire et opératoire possible pour des recherches sémiotiques renouvelées et ancrées dans les sciences de la culture. À cet égard, cette contribution vise aussi à confronter les formes de vie avec d’autres notions proches telles celles de sémiosphère (Lotman, 1966), de styles de vie (Landowski, 1997; 2004) et d’idéal de vie (Perusset, 2020).

A pesquisa sobre as escritas permaneceu por muito tempo subordinada à Linguística, conforme uma concepção representativa-fonocêntrica simplista em que a escrita se encontrava submetida à língua. Essa posição é agora insustentável. Graças ao encontro entre Semiótica, Linguística e Antropologia, a pesquisa sobre as escritas foi renovada. A partir dos estudos das semióticas figurativas e plásticas, deu-se a reintrodução do imagético e a tomada de consciência da espacialidade no estudo das escritas. A abordagem antropológica indicou que a escrita e seus mecanismos apresentam um conjunto de valores culturais, sendo um meio privilegiado para a produção ideológica e simbólica de um povo. A linguística abriu-se assim a outras disciplinas, passando a considerar a escrita como um continuum pluri-semiótico que comporta intrinsecamente uma dimensão icônica e uma dimensão linguística.

Looking at both successful (and unsuccessful) attempts to crack ancient undeciphered writing systems over the course of history, the aim of this paper is to study how decipherment can contribute to a general theory of writing. It is argued that two conditions have to be fulfilled for decipherment to be possible; it has to be acknowledged: (1) that writing is a system possessing an autonomous internal organization, and (2) that the relationship between this system and the linguistic system cannot be envisioned as an equivalence, as a translation or as a transcoding, but has to be seen as a synchronization or adjustment. This synchronization is based either on parallelism or on symbolization and distribution. The decipherment of Egyptian hieroglyphs is a good illustration of the first option, as it relies on a comparative approach that resorts to analogy. In the second case (closer to cryptography), internal reconstruction is favored and the formal regularities of the system are the starting point. Ventris’ decipherment of Linear B is a famous example of such an approach. As such, decipherment can be envisioned as an interpretative process that allows one to (re)construct a system, from its substance to its form, and the systematic character of the decipherment is the guarantee of its validity.

Mycosubtilin belongs to the family of lipopeptides. Different isoforms with various antifungal activities can be obtained according to the length and the isomery of the fatty acid. In this work, the activities of the mycosubtilin isoforms were first studied against the pathogen Aspergillus niger, revealing the high activity of the anteiso-C17 isoform. Modification of the mycosubtilin isoform patterns during cultures of the natural strain Bacillus subtilis ATCC 6633 was then investigated through amino acid feeding experiments. In parallel, single-gene knockouts and single-gene overexpression, leading to the overproduction of the anteiso-C15 fatty acid chains, were predicted using informatics tools which provide logical reasoning with formal models of reaction networks. In this way, it was in silico predicted that the single overexpression of the ilvA gene as well as the single knockout of the codY gene may lead to the overproduction of anteiso-C15 fatty acid chains. For the first time, it has been demonstrated that overexpression of ilvA helps to enhance the furniture of odd anteiso fatty acids leading to a favored mycosubtilin anteiso-C17 production pattern (+41%). Alternatively, a knock-out codY mutant led to a higher furniture of even iso fatty acids, leading to a favored mycosubtilin iso-C16 production pattern (+180%). These results showed that increased selective synthesis of particular isoforms of mycosubtilin through metabolic engineering is feasible, disclosing the interest of these approaches for future development of lipopeptide-producing strains.

Having as a starting point Saussure’s studies on the sign and the praxis dimension of language, this article discusses the organization of a theory of semiotic enunciation and, more precisely, the concept of enunciative praxis. Such notion refers to the operations that, by assuming the system of narrative deep structures, produce semiotic configurations sufficiently stabilized to be available for other uses. These configurations are understood in a constant movement of reshaping of forms, which is therefore responsible for discourse renewal. Translated by: Raíssa Medici de Oliveira UNESP (Câmpus Araraquara) Renata Cristina Duarte UNESP (Câmpus Araraquara) --- DOI: http://dx.doi.org/10.22409/gragoata.2017n44a968

Introduction to Gragoatá 44. --- DOI: http://dx.doi.org/10.22409/gragoata.2017n44a1101

In a structural point of view, paradigms are in principle and generally classifications which are reserved to the language system, to its immanent structure. The purpose of this study is to show that in process, in semiotic manifestation, syntagmatic organizations are also set in potential paradigms. For generative semiotics, the manifestation of processes and the semiosis always leads to confrontation and imperfection : manifestation, processes and semiosis are, on one side, generated, and on the other side, attested and observed. It is in this confrontation that incompleteness, imperfections, substitutions appear, and more generally, the potential presence (“in power”) of syntagmatic possibilities, or of complete semiosis, available to access manifestation. It follows that it is not possible to reserve the paradigmatic operating principle to paradigms in the strict sense. So there are paradigms of paradigms, paradigms of syntagms, paradigms of processes, and even paradigms of semiosis : it would be in fact an invitation to overhaul the organization of linguistic and semiotic immanence.The author puts forward the following words : manifestation, existential modes, syntagmatic potentials, paradigms of syntagms, semiosis, slip, forms of living.

O artigo analisa os diversos tratamentos do afeto no campo das pesquisas semióticas abertas por Greimas. Ele mostra as premissas, seus desenvolvimentos, seus desaparecimentos e seus ressurgimentos e, mais geralmente, as complementariedades e as derivações solidárias. Em Semântica estrutural, Greimas lançava já algumas bases como a categoria tímica e a proprioceptividade. Muito mais tarde, a teoria das paixões reencontrará a tensividade, e Claude Zilberberg fará do afeto o ponto de origem de toda tensividade. Segue a contribuição de Eric Landowski, que, tratando da experiência vivida, torna obsoleta a distinção entre paixões lexicalizadas e “paixões sem nome”. Também serão mencionadas as proposições de Jacques Geninasca, Herman Parret e, mais recentemente, de Waldir Beividas. Mas insistiremos sobretudo sobre a via desenvolvida pelo próprio Greimas em De l’Imperfection, a partir da experiência estética na própria existência.

Uma das dificuldades constantes da semiótica é a distância que se instalou entre as especulações teóricas e as reflexões epistemológicas, de um lado, e os métodos e resultados da descrição e da interpretação dos dados, de outro. Neste trabalho, tentando solucionar o problema, propomos inverter a ordem habitual das prioridades e considerar que a semiótica deve ser conduzida pela metodologia e não diretamente pela epistemologia. Acrescentamos dois critérios a esse pressuposto de base: (i) a capacidade que tem o método para dar conta da singularidade dos objetos analisados e (ii) a articulação desse método com o das disciplinas vizinhas que se ocupam dos mesmos objetos. Nossa proposta será articulada em duas etapas, portanto: (1) um exame detalhado, no âmbito da teoria da linguagem, das condições sob as quais é possível, ao mesmo tempo que a estruturação da forma, levar em consideração as variações substanciais e (2) uma reflexão, fundada nos resultados do primeiro ponto, a respeito do tratamento das singularidades práticas na interface entre a semiótica e a etno-antropologia. O conjunto desta proposta é uma contribuição em favor da diversificação controlada dos regimes metodológicos da semiótica.

This is a semiotic essay in which the production of meaning is analyzed during the course of action. As it is an opened course, its nature and projective scope are relevant,whichplacesus inthe actionfieldas language, and also in the syntagmatic settings needed to maintain the congruence. In order to achieve it, the course of action would have to use adaptation, regulation, adjustment, memory and anticipation, etc. For example, there is a typology of traces which leads us from the forms to the interpretative processes, as well as to the concordance or discordance, and to the interpretation rules.

Greimas définissait sa sémiotique comme un « projet scienti-fique », mettant ainsi l’accent sur une construction en cours. Il nous faut donc comprendre pourquoi elle se présente comme un pro-gramme ouvert dans de multiples directions. La sémiotique de Greimas définit une série de problèmes à traiter, et pose des jalons au très long terme. Greimas lui-même ne traite qu’une partie de ces problèmes, et les autres restent en attente des réponses que ses successeurs peuvent apporter. Dans cette perspective, il avait lui-même encouragé ses collaborateurs à se répartir les différentes voies ouvertes dans son programme. Ces différentes évolutions sont connues : la sémiotique subjectale, la sémiotique tensive, la sémiotique morpho-dynamique, la sociosémiotique, la sémiotique de la perception, notamment. Il est donc possible aujourd’hui d’évaluer les effets de ces parcours de recherche. Mais de nom-breux problèmes restent encore ouverts : le parcours génératif de l’expression, la diversité, les conditions et l’instabilité des sémioses, le dialogue avec les autres « sciences du sens ». Et enfin, le projet lui-même doit être reconfiguré et mis à jour sous toutes les dimen-sions de son ancrage dans le monde d’aujourd’hui, près de soixante ans après sa conception.

A leitura atenta de algumas das obras de Greimas, com destaque especial para o estudo de narrativas míticas nos dois volumes de Sobre o sentido (1975 [1970]; 2014 [1983]), aponta para a intuição antropológica de sua proposta e o alcance dos esquemas narrativos pertinentes para o que poderia ser uma abordagem semioantropológica. Como forma sintagmática do “sentido da vida”, o esquema narrativo canônico abre caminho ao exame dos regimes semióticos, à descrição das formas de vida e das práticas semióticas; logo, à análise do nível propriamente semiótico das produções culturais. Propõe-se, assim, com a ajuda da antropologia contemporânea, esboçar uma articulação entre os tipos de esquemas práticos (produtores de objetos culturais e simbólicos) e os modos de existência (coletivos), uma teoria e uma tipologia das práticas que possa diminuir a distância entre as semióticas da cultura e as semióticas textuais, devolvendo à teoria a sua dimensão antropológica, tal como Greimas havia começado a delineá-la.

En 2012, paraît un ouvrage à la fois essentiel et perturbant pour qui s’intéresse à la science de l’écriture : Dernières leçons, Collège de France, 1968 et 1969, dont huit leçons sont consacrées à la question de l’écriture (sur les 16 leçons que comporte le volume). Le contenu de ces leçons était resté inédit jusque là. Au moment où Benveniste rédige ces cours sur l’écriture, la science de l’écriture est à un tournant : à cette époque, elle est dominée par une conception représentative issue de la tradition saussurienne (l’écriture comme code second destiné à représenter la langue). L’heure est à la remise en question, avec, en particulier Derrida. Grâce à un dialogue entre sémiotique, anthropologie et une conception revisitée de la linguistique, la science de l’écriture se trouve peu à peu profondément renouvelée. Les réflexions de Benveniste ont-elles contribué à ce renouveau de la science de l’écriture ? Et plus précisément, ses propositions ont-elles contribué à renouveler l’approche dite linguistique ? Nous essayerons de comprendre quelles implications ses réflexions ont eues, mais aussi quelles en sont les limites. Nous terminerons par des pistes pour un point de vue global sur le problème.

Este texto, escrito en homenaje a Eric Landowski, no trata sobre la sociosemiótica de Landowski ni es un texto a propósito de Eric. Quiere ser solamente un texto «para» Eric Landowski. Se habla aquí de los medios, que a veces le han interesado en una perspectiva sociosemiótica; y nos esforzamos por hacerlo sin mucha jerga y sin tecnicismos, que con frecuencia lo han irritado con nosotros, semiotistas. Hablamos aquí de nuestra condición de hombres y de interpretantes sometidos a todas las manipulaciones, que es su preocupación principal, e intentamos hacerlo sobre el horizonte de una exigencia ética, que es su marca de fábrica.

A pesquisa, de modo geral, deixou de pertencer apenas ao domínio de pesquisadores profissionais, na medida em que, atualmente, é uma das grandes funções das sociedades globalizadas, participando, consequentemente, dos modos de construção de identidades que essas sociedades propõem. Se a semiótica quer reconhecer-se ainda como disciplina de vocação científica, não pode escapar desse movimento global. Ao propor um corpo de conceitos e de métodos para questionar as práticas, os textos, os objetos, as interações sociais, as formas de vida e os modos de existência coletivos e da coletividade, a semiótica tem condições de construir esses sentidos, especialmente se trabalhar em colaboração com as outras ciências humanas e sociais que contribuem para edificar, cada uma de seu próprio ponto de vista, essa arquitetura das significações humanas. Neste artigo, tendo em vista esse cenário, buscaremos apontar quais são alguns dos desafios, dos avanços e das perspectivas da semiótica para o mundo de hoje. Ainda que não esgotemos as possibilidades de um projeto integral no âmbito da semiótica, acreditamos que pudemos escolher alguns exemplos que ocupam lugar de destaque nas preocupações atuais de nossa sociedade e que são objetos de uma demanda social e política mais urgente. Esperamos, portanto, que nossa reflexão seja suficiente para chamar a atenção de outros pesquisadores para os desafios sociais do século XXI, o que, ao nosso ver, deve ser uma das “vocações” da semiótica.

Since centuries vegetable oils are consumed as human food but it also finds applications in biodiesel production which is attracting more attention. But due to being in competition with food it could not be sustainable and leads the need to search for alternative. Nowdays microbes-derived oils (single cell oils) seem to be alternatives for biodiesel production due to their similar composition to that of vegetable oils. However, the cold flow properties of the biodiesel produced from microbial oils are unacceptable and have to be modified by an efficient transesterification. Glycerol which is by product of transesterification can be valorised into some more useful products so that it can also be utilised along with biodiesel to simplify the downstream processing. The review paper discusses about various potent microorganisms for biodiesel production, enzymes involved in the lipid accumulation, lipid quantification methods, catalysts used in transesterification (including enzymatic catalyst) and valorisation of glycerol.

This paper proposes to develop the semiotics of practices. The creation of the value of an object in the course of an action entails, at a prior point, its iconic stabilisation and, at a later point, the consequent semiotisation of the situation. Specifically, the paper analyses the filmed interaction of a child with a rope and an educator. It highlights the process and the constraints of the practical investment of the rope, which appear to constitute a narrative sequence : (i) corporal assimilation of the rope (acquisition of competence) — (ii) iconisation (ritualisation of the performance) — (iii) grammaticalisation (sanction). In such a sequence, the paper focuses on the very recursive way in which the rope is defined : in a figurative way, as a circle for the game, and in a figural, chorematic way, as a spatial scheme for the child’s game. Starting from such semiotisation, it appears that actantial and thematic roles, as well as possible predications, are distributed onto the persons and the other objects in the situation : the child, the educator, other children, other objects…

α-Pinene oxide lyase is able to catalyze the cleavage of both rings of α-pinene oxide to form cis-2-methyl-5-isopropylhexa-2,5-dienal (isonovalal) with no cofactor requirements. This bioconversion, when carried out under biphasic conditions (water/hexadecane) by Pseudomonas rhodesiae CIP 107491, allows the accumulation of a very high concentration of the product. Nevertheless, the reaction stopped due to the loss of enzyme activity, which has been demonstrated to be an irreversible phenomenon. The enzyme was purified by chromatographic methods to study the reasons of its instability. Bioconversion with pure enzyme showed that a protein precipitation occurred at the liquid-liquid interface, giving rise to a decrease in soluble protein and in residual enzymatic activity. The rate of decrease in soluble protein concentration was not related to the presence of the precursor, which indicated that the inactivation was interfacial, i.e. due to the direct contact of the enzyme with the hexadecane layer. This phenomenon was not present when crude enzymatic extract was used as a biocatalyst. Biomass components present in this extract thus had a protective effect against interfacial phenomena, demonstrating that α-pinene oxide lyase purification does not attract much practical interest for isonovalal production.

The aim of this work is to demonstrate the role of conidial spores as a reservoir of glucose oxidase and their stability as a biocatalyst in the bioconversion reaction for the production of gluconic acid. Solid-state fermentation (SSF) was carried out in fixed-bed column bioreactor for the production of Aspergillus niger spores. Growth parameters, sporulation and kinetics of gluconic acid production were analysed at different time intervals during the course of SSF. Spores of different age (48–216 h) were used as biocatalysts in the bioconversion reaction. Spores harvested at a later period of SSF (196 h) produced high titres of gluconic acid (30 g/L) in the bioconversion medium when compared to the spores harvested at early (48 h) stages of SSF (2.2 g/L). Spores (harvested at 200 h and stored in freezer for 91 days) exhibited the same glucose oxidase activity and served as an active and stable catalyst when compared to the fresh spores, showing that aging (storage) did not affect enzymes present in the spores, which suggested that the spores acted as an efficient enzyme reservoir. Yields close to 93 % were obtained with 98 g/L of gluconic acid production, corresponding to an average productivity of 1.7 g/(L·h). The stability of the enzyme in the spores and the ability of conidia to be stored for a long time without the loss of activity add specific advantage to the bioconversion process.

Gluconic acid is a mild organic acid derived from glucose by a simple oxidation reaction. The reaction is facilitated by the enzyme glucose oxidase (fungi) and glucose dehydrogenase (bacteria such as Gluconobacter). Microbial production of gluconic acid is the preferred method and it dates back to several decades. The most studied and widely used fermentation process involves the fungus Aspergillus niger. Gluconic acid and its derivatives, the principal being sodium gluconate, have wide applications in food and pharmaceutical industry. This article gives a review of microbial gluconic acid production, its properties and applications.