Comparison of Pigment Production by Filamentous Fungal Strains under Submerged (SmF) and Surface Adhesion Fermentation (SAF).

Although synthetic colorants are widely used in many industries due to their high stability at different conditions in industrial processes, evidence of its negative impact on health and the environment is undeniable. Filamentous fungi are well known for their use as alternative sources to produce natural pigments. However, an adequate comparison of the productivity parameters between the fermentation systems could be limited to their heterogeneous conditions. Even though Solid-State Fermentations (SSF) on natural substrates are widely used for pigments production, complex media, and non-controlled variables (T, pH, medium composition), these systems could not only hamper the finding of accurate productivity parameters, but also mathematical modeling and genomics-based optimization. In this context, the present study screened five pigment-producing fungi by comparing Submerged (SmF) and Surface Adhesion Fermentation [biofilm (BF) and Solid-State (SSF)] with defined media and controlled variables. For this purpose, we used the same defined media with sucrose as the carbon source for pigment production on SmF, BF, and SSF, and BF and SSF were carried out on inert supports. Five molecularly identified Penicillium and Talaromyces strains isolated from the Peruvian rainforest were selected for their ability to produce yellowish-orange colorants. Highest productivities were obtained from T. brunneus LMB-HP43 in SmF (0.18 AU/L/h) and SSF (0.17 AU/L/h), and P. mallochii LMB-HP37 in SSF (0.18 AU/L/h). Both strains also exhibited the highest yields (AU/g biomass) in the three fermentation systems, reaching values greater than 18-folds in SSF compared to the other strains. Conversely, T. wortmannii LMB-HP14 and P. maximae LMB-HP33 showed no ability to produce pigments in the SSF system. The performed experiments accurately compared the effect of the fermentation system on yield and productivity. From this, further genomics approaches can be considered for an extensive analysis of pigment synthesis pathways and a genomics-driven optimization in the best fermentation system.

Tempo and rates of diversification in the South American cichlid genus Apistogramma (Teleostei: Perciformes: Cichlidae).

Evaluating biodiversity and understanding the processes involved in diversification are noticeable conservation issues in fishes subject to large, sometimes illegal, ornamental trade purposes. Here, the diversity and evolutionary history of the Neotropical dwarf cichlid genus Apistogramma from several South American countries are investigated. Mitochondrial and nuclear markers are used to infer phylogenetic relationships between 31 genetically identified species. The monophyly of Apistogramma is suggested, and Apistogramma species are distributed into four clades, corresponding to three morphological lineages. Divergence times estimated with the Yule process and an uncorrelated lognormal clock dated the Apistogramma origin to the beginning of the Eocene (≈ 50 Myr) suggesting that diversification might be related to marine incursions. Our molecular dating also suggests that the Quaternary glacial cycles coincide with the phases leading to Apistogramma speciation. These past events did not influence diversification rates in the speciose genus Apistogramma, since diversification appeared low and constant through time. Further characterization of processes involved in recent Apistogramma diversity will be necessary.

Isolation and identification of proteolytic, amylolytic, lipolytic, and chitinolytic bacteria from shrimp waste / Aislamiento e identificación de bacterias proteolíticas, amilolíticas, lipolíticas y quitinolíticas de residuos de langostinos

Abstract Bacteria and microbial enzymes are biocatalysts and can be used as an alternative to industrial chemical processes. The present study focused on isolating and identifying bacterial strains from shrimp waste, that produce amylases, lipases, proteases and chitinases with potential use on shrimp waste treatment. Thirtytwo bacterial strains were isolated, phenotypically characterized, and identified by the API system and the molecular analysis of the 16S rDNA. It was found that 28.13% of the isolated bacterial strains had amylolytic capacity, 87.50% lipolytic, 96.88% proteolytic and 28.13% chitinolytic capacity on agar plates with specific substrates. The genera Bacillus, Burkholderia, Ochrobactrum, Vibrio, Pseudomonas and Shewanella were identified. Bacteria with enzymatic capacities isolated in the present study, could be used to obtain by-products from shrimp waste as well as other industrial applications.

Resumen Las bacterias y enzimas microbianas son biocatalizadores y pueden ser usadas como alternativa en los procesos químicos industriales. El presente estudio se centró en aislar e identificar cepas bacterianas a partir de desechos de langostinos, capaces de producir amilasas, lipasas, proteasas y quitinasas, que tuvieran potencial aplicación en el tratamiento de residuos de langostinos. Se aisló treinta y dos cepas bacterianas, caracterizadas fenotípicamente e identificadas mediante el sistema API 20 y mediante análisis molecular basado en el ADNr 16S. Se encontró que el 28.13% de las cepas bacterianas aisladas tenían capacidad amilolítica, 87.50% lipolítica, 96.88% proteolítica y 28.13% capacidad quitinolítica en placas de agar con sustratos específicos. Los géneros identificados fueron Bacillus, Burkholderia, Ochrobactrum, Vibrio, Pseudomonas y Shewanella. Las bacterias con capacidades enzimáticas aisladas en el presente estudio, podrían ser usadas para obtener subproductos de los desechos de langostinos, así como en otras aplicaciones industriales.