Resumen Este trabajo tuvo el objetivo de determinar las variantes genéticas de PAX9, MSX1 y AXIN2 en probandos mayas con agenesia dental no sindrómica (ADNS) de Yucatán, México. Se realizó secuenciación tipo Sanger del ADN de exones específicos de PAX9, MSX1 y AXIN2 en siete probandos Mayas con ADNS familiar atentidos en clínicas ortodónticas de Mérida, Yucatán, México. Se analizaron cuatro genomas de personas sanas con propósitos de comparación. Dos probandos Mayas fueron diagnosticados con oligodoncia (14 y 16 dientes perdidos) y cinco con hipodoncia (1-2 dientes perdidos). Se detectó la variante genética rs8670 en MSX1; PAX9 presentó rs12881249 y rs4904210; en AXIN2 se encontraron rs1060502133, rs1060502139, rs147716924, rs1330822418, rs769741903, rs9915936, rs1133683 y rs1234437759. Las variantes detectadas en PAX9, MSX1 y AXIN2 se clasificaron como benignas y ya habían sido previamente reportadas. En conclusión, el gen AXIN2 exhibió el mayor número de variantes. Ya que algunas de ellas también estuvieron presentes en genomas de personas sanas, se requieren estudios funcionales y epidemiológicos adicionales para determinar la significancia clínica de las variantes encontradas y los fenotipos asociados.

Abstract The present study aimed to determine the genetic variants of PAX9, MSX1, and AXIN2 in Mayan probands with non-syndromic dental agenesis (NSDA) from Yucatan, Mexico. We sequenced DNA of specific exons of the PAX9, MSX1, and AXIN2 genes by using the Sanger method in seven Mayan probands with familial NSDA attending orthodontic clinics in Merida, Yucatan, Mexico. We bioinformatically analyzed four genomes of unaffected people with Mayan ancestry for comparative purposes. Two Mayan probands had oligodontia (14 or 16 missing teeth) and five had hypodontia (1-2 missing teeth). We found the following genetic variants: rs8670 in MSX1; rs12881240 and rs4904210 in PAX9; and rs1060502133, rs1060502139, rs147716924, rs1330822418, rs769741903, rs9915936, rs1133683, and rs1234437759 in AXIN2. The genetic variants in PAX9, MSX1, and AXIN2 in Mayan probands with familial NSDA were benign and have previously been reported. In conclusion, the AXIN2 gene exhibited the highest number of known variants. Because some variants were also present in the genomes of unaffected people, additional functional and epidemiological studies are required to address their clinical significance and associated phenotypes.

Resumen La guayaba (Psidium guajava) se puede caracterizar por su diversidad genética y sus cualidades morfológicas, fisicoquímicas y biológicas, las cuales dependen de factores exógenos como: cultivo agronómico, época de cosecha y madurez. Caracterizada por su contenido de carbohidratos (13.2%), grasas (0.53%), proteínas (0.88%) y gran contenido de humedad (84.9%). Es importante caracterizar la guayaba ‘media china’ cultivada en el municipio de Juárez, Michoacán, con el objetivo de mejorar características morfológicas, fisicoquímicas, biológicas, nutritivas y variables estadísticas en control de calidad para correlacionarlas a la posibilidad de industrializarla y comercio internacional. Para tal fin, se utilizó la metodología sistémica de los ‘diagramas de bloques de confiabilidad’ que incluyó muestreo aleatorio de la guayaba para estudio, en el que se determina: peso, diámetros longitudinal, transversal, pulpa, espesor y pH. Se obtuvieron; media aritmética, varianza y desviación estándar, variables para graficar y comparar con normas establecidas para comercio nacional e internacional. Como resultado se encontró que, la guayaba procedente del municipio de Juárez, Michoacán, presentó los mejores resultados en su caracterización. La guayaba cultivada en la huerta del municipio de Calvillo en el estado de Aguascalientes presentó resultados menores, se observó que fue superada la calidad por la fruta de Juárez Michoacán. Las características en tamaño, apariencia visual, contenido de semilla del fruto, observadas en las muestras compiten con las de las variedades comerciales. El análisis de esta investigación infiere las siguientes conclusiones: el sistema productivo del cultivo en el estado de Michoacán y Aguascalientes, están en condiciones de ofertar guayaba de buena calidad para su comercialización nacional e internacional, debido a las buenas prácticas agrícolas aplicadas y su registro al Servicio Nacional de Sanidad Inocuidad y Calidad Agroalimentaria de la Dirección General de Sanidad Vegetal de la Secretaría de Agricultura y Desarrollo Rural.

Abstract Guava (Psidium guajava) can be characterized by its genetic diversity and its morphological, physicochemical and biological attributes, which depend on exogenous factors such as: agronomic cultivation, harvest season and maturity. Characterized by its content of carbohydrates (13.2%), fats (0.53%), proteins (0.88%) and high moisture content (84.9%). It is important to characterize the ‘media china’ guava grown in the municipality of Juárez, Michoacán, with the aim of improving morphological, physicochemical, biological and nutritional characteristics and statistical variables in quality control to correlate them to the possibility of industrializing it and international trade. For this purpose, the systemic methodology of ‘reliability block diagrams’ was used, which included random sampling of guava for study, in which the following are determined: weight, longitudinal diameter, transverse diameter, pulp, thickness and pH. The following were obtained: arithmetic mean, variance and standard deviation, variables to graph and compare with established standards for national and international trade. As a result, it was found that guava from the municipality of Juárez, Michoacán showed the best results in its characterization. The guava grown in the orchard of the municipality of Calvillo in the state of Aguascalientes presented lower results, it was observed that the quality was exceeded by the fruit of Juárez, Michoacán. The characteristics in size, visual appearance, seed content of the fruit, observed in the samples compete with those of commercial varieties. The analysis of this research infers the following conclusions: the productive system of the crop in the state of Michoacán and Aguascalientes is in a position to offer guava of good quality for national and international trade, due to the good agricultural practices applied and its registration in the National Service of Health, Safety and Agrifood Quality of the General Directorate of Plant Health of the Secretariat of Agriculture and Rural Development.

Abstract Jumbo squid (Dosidicus gigas) muscle hardness has been related to hydroxylysyl-pyridinoline (HP) formation (collagen fibre stabilization) via condensation of oxidized ε-amino groups of lysine and/or hydroxylysine by lysyl oxidase (LOX). Previously published literature has suggested the presence of LOX isoforms in squid muscle. Thus, the objective of the present research was to test the hypothesis that squid LOX isoforms exist in fresh mantle muscle. A semi-pure LOX extract (SPLE) was used to perform an immunoblotting assay using two commercial human-LOX antibodies. Furthermore, SPLE (specific activity of 20 mU/mg of protein) was tested in vitro for possible HP formation using several collagenous materials. Immunoblotting assay confirmed the presence of squid LOX at 32 kDa and its isoforms at 34 kDa and 24 kDa. Although LOX oxidized ε-amino groups on collagenous materials, no HP formation was detected. However, the latter could promote interesting collagen functional modifications.

Abstract Loricariid catfish (Pterygoplichthys disjunctivus [Weber, 1991]) has invaded water catchments throughout the world, due to the lack of predators and high fecundity. An approach to control its population could be using its roe as food; however, more knowledge is needed. Thus, the present study aimed to evaluate the shelf-life of fresh loricariid catfish roe stored in ice, as an approach for possible food utilisation. Physicochemical characteristics (moisture content, aw, pH, hardness, and colour), protein electrophoresis (SDS-PAGE), amino and fatty acid contents, oxidative stability (TBARS) and microbiology of roe were analysed at 0, 2, 4, 6, 11, 15 and 21 days. Moisture content (58.5 ± 2.1 vs. 60.4 ± 1.2%), aw (0.89) and pH (5.87 ± 0.14 vs. 5.96 ± 0.03) were shelf-stable (initial vs. final day, respectively). SDS-PAGE showed minor hydrolysis of its protein. Ice storage increased roe free amino acid concentration, confirming proteolysis of its proteins/peptides with not impact on the fatty acid content and TBARS (2.4–3.3 mg malonadehyde/kg sample). Thus, ice storage of fresh loricariid catfish (P. disjunctivus [Weber, 1991]) roe, under the study conditions, proved to be an effective preservation method for its food utilisation, maintaining its physicochemical and microbiological characteristics for up to 20 days.

Abstract Enormous amounts of by-products and waste are generated during the processing of seafood, sometimes representing about 65% of the raw material employed. Seafood by-products (SB) include solid waste such as skin, head, viscera, trimmings, and bones; however, liquid wastes (effluents) derived from operations such as washing, thawing, cooking and the production of fishmeal are also produced. SB contain considerable amounts of protein and others biomolecules, which has been regularly processed as food ingredients for animal nutrition. But also, sometimes SB are used as fertilizers or discarded to environment without a previous treatment. Nowadays, there is an increasing interest in adding value to the protein material within SB by improving their properties through hydrolysis and thus releasing of peptides with bioactive properties. Thus, this review aims to present an overview of the potential of SB, focused on effluents, as a source of protein hydrolysates, summarizing their methods of production, bioactive property evaluation and structural characteristics.

Abstract The present research work determined the effect of the stable and oscillating seawater temperature at three different levels (21, 24 and 28°C), on the physiological condition of the lion’s paw scallop Nodipecten subnodosus. For this, we evaluated the following physiological indicators: adenosine triphosphate content (ATP), glycogen and total carbohydrates, as well as muscle yield index (MYI) and adenylated energy charge, which were determined in the abductor muscle of organisms, extracted directly from the lagoon and after the treatments application. It was found that in the experiment, concentrations of ATP, glycogen content, total carbohydrates, and MYI decreased significantly (P<0.05) after the application of treatments. No effect of temperature level and application form (oscillating and constant) on MYI and CEA was found, however, glycogen content showed a significant affect only from the temperature level, being organisms exposed to 28°C statistically different from those of 24 and 21°C. In conclusion, only the acclimatization temperature level affected the physiological condition of the lion’s paw scallop, being the organisms acclimatized to 28°C the most affected.

Resumen El presente trabajo de investigación determinó el efecto de la temperatura estable y oscilante del agua de mar a tres diferentes niveles (21, 24 y 28°C), sobre la condición fisiológica de la almeja mano de león Nodipecten subnodosus. Para ello, se evaluaron los siguientes indicadores fisiológicos: contenido de adenosina trifosfato (ATP), glucógeno y carbohidratos totales, así como índice de rendimiento muscular (IRM) y carga energética adenilada (CEA), los cuales se determinaron en el músculo abductor de organismos extraídos directamente de la laguna y después de la aplicación de los tratamientos. Se encontró que, en el experimento, las concentraciones de ATP, contenido de glucógeno, carbohidratos totales, e IRM disminuyeron significantemente (P<0.05) después de la aplicación de los tratamientos. No se encontró un efecto del nivel de temperatura y la forma de aplicación (oscilante y constante) en el IRM y CEA, sin embargo, en el contenido de glucógeno se obtuvo un afecto significativo solo del nivel de temperatura, siendo los organismos sometidos a 28°C diferentes (P<0.05) a los de 24 y 21°C. Por lo tanto, se concluyó, que solo el nivel de temperatura de aclimatación afectó la condición fisiológica de la almeja mano de león, siendo los organismos aclimatados a 28°C los más afectados.

The Pampa Hermosa national sanctuary (SNPH) is an important area because it preserves relict montane forests of the Peruvian central Yungas where studies of bat’s diversity are scarce. Our objective was to document the species diversity and composition of bats communities in Pampa Hermosa and make comparisons with other Peruvian Yungas forests ranging between 1200-2000 m. We sampled four localities: Podocarpus (1900 m), Los Cedros (1600 m), Santa Isabel (1450 m) and Nueva Italia (1370 m) by using 560 mist-nights. Our results show 36 species distributed in families Phyllostomidae (30 spp.), Vespertilionidae (5 spp.) and Molossidae (1 sp.). According to the estimators Chao 1 and Chao 2, we found 77% and 42% of the species in the study area, respectively. The rank-abundance curves point to Carollia brevicauda as the most abundant in all localities; abundance of Vampyressa melissa is highlighted in Los Cedros and Podocarpus. There is a significant inverse relationship between species richness and elevation (r = -0.90, P = 0.014). Altitudes of 1200-1600 m show a species richness (35 spp.) higher than other Yungas forests, and a greater similarity to those in Manu (Ij = 0.59); on the other hand, richness at altitudes of 1600-2000 (14 spp.) was the second highest after Manu (21 spp.) and more similar to San Ramon (Ij = 0.30). Values of complementarity were higher between Pampa Hermosa and other forests in the Peruvian Yungas, ranging from 55-76% (1200 - 1600 m) to 70-83% (1600 - 2000 m). These results indicate there is a high β diversity in the bat communities from the Peruvian Yungas; however, we have to take into account the disparate sampling efforts among the evaluated localities and that additional research in areas of the SNPH not yet explored must give a stronger support to our results.

El Santuario Nacional Pampa Hermosa (SNPH) es un área protegida importante debido a que protege los relictos de los bosques montanos de las Yungas centrales del Perú, donde los estudios de la diversidad de murciélagos son escasos. Nuestro objetivo fue documentar la diversidad y composición de los murciélagos del SNPH y compararlo con otros bosques de las Yungas peruanas en el rango de 1200 - 2000 m. Se evaluaron cuatro localidades: Podocarpus (1900 m), Los Cedros (1600 m), Santa Isabel (1450 m) y Nueva Italia (1370 m). Se registraron 36 especies de murciélagos en las familias Phyllostomidae (30 spp.), Vespertilionidae (5 spp.) y Molossidae (1 sp.) con un esfuerzo de 560 redes-noche. Los estimadores Chao 1 y Chao 2 indicaron que se cubrió el 77% y 42% de las especies en la zona de estudio, respectivamente. Las curvas de rango-abundancia muestran a Carollia brevicauda como la más abundante en todas las localidades; se resalta la abundancia de Vampyressa melissa en las localidades de Los Cedros y Podocarpus. Se muestra una relación inversa significativa entre la riqueza de especies y la elevación (r = -0.90, P= 0.014). En rangos de 1200-1600 m, la riqueza del SNPH (35 spp.) fue mayor que en las otras Yungas presentando una mayor similitud con el Manu (Ij = 0.59); por otro lado, en rangos de 1600 - 2000 la riqueza del SNPH (14 spp.) fue la segunda más alta después del Manu (21 spp.), presentando una mayor similitud con San Ramón (Ij = 0.30). Los valores de complementariedad fueron altos entre el SNPH y los bosques de Yungas, entre 55-76% (1200-1600 m) y entre 70-83% en (1600-2000 m). Estos resultados indican que la diversidad β de los murciélagos en las Yungas peruanas es alta; sin embargo, debemos tomar en cuenta los esfuerzos dispares entre las localidades comparadas y que se requiere más trabajo de campo en zonas de vida y elevaciones aun no exploradas del SNPH para resultados más precisos.

Currently, the state of Queretaro is a major wine producer in Mexico; however, marketing these wines is difficult due to their lack of quality and typicity, factors in which wine yeasts play an essential role. Saccharomyes are responsible for ethanol production and non-Saccharomyes (nS) can provide metabolites that enhance wine quality, so their use in mixed cultures is of great interest. In this study, yeasts isolated from the spontaneous fermentation of grape musts from three local vineyards were differentiated as nS in lysine medium. Their β-glucosidase activity and SO2 (30 mg·L-1) and ethanol (6 %) tolerances were evaluated. Outstanding yeasts were tested in mixed microvinifications along with S. cerevisiae (K1-V1116) and identified through analysis of the 26S gene. Of 197 isolated strains, 146 were differentiated as nS; 90 showed βglucosidase activity and eight (NB1, NA4, NB27, NB31, NB39, NR77, NR90, NB108) were selected based on tolerance tests, being identified as belonging to the genus Hanseniaspora. The nS did not interfere with the fermentative activity of K1-V1116, finding no differences in the parameters evaluated between the wines obtained by mixed cultures and the control (K1-V1116). The values obtained for pH, total acidity, volatile acidity and alcohol were considered to be of acceptable quality for dry wines. The strain NB39 stood out for its glycerol production, obtaining the highest value (7.45 g·L-1). We conclude that there are nS yeast strains in the region with enological potential to be used at a commercial level.

Actualmente el estado de Querétaro es un importante productor de vinos en México; sin embargo, éstos difícilmente se comercializan debido a su falta de calidad y tipicidad, factores en que las levaduras vínicas juegan un papel esencial. Las Saccharomyes son responsables de la producción de etanol y las no-Saccharomyes (nS) pueden aportar metabolitos que mejoren la calidad, por lo que su uso en inóculos mixtos es de gran interés. En este estudio, levaduras aisladas de la fermentación espontánea de mostos de uva de tres viñedos queretanos se diferenciaron como nS en medio-lisina. Se evaluó su actividad β-glucosidasa, su tolerancia a SO2 (30 mg·L-1) y a etanol (6 %). Aquellas sobresalientes se probaron en microvinificaciones mixtas con Saccharomyces cerevisiae (K1-V1116) y se identificaron mediante el análisis del gen 26S. De 197 cepas aisladas, 146 resultaron nS; 90 presentaron actividad βglucosidasa y ocho (NB1, NA4, NB27, NB31, NB39, NR77, NR90, NB108) se seleccionaron con base en los ensayos de tolerancia, identificándose como pertenecientes al género Hanseniaspora. Las nS no interfirieron en la actividad fermentativa de K1-V1116; ya que no se encontraron diferencias en las variables evaluadas entre los vinos elaborados con cultivos mixtos y el control (K1-V1116). Se obtuvieron valores de pH, acidez total, acidez volátil y alcohol, considerados de calidad aceptable para vinos secos. La cepa NB39 destacó en su producción de glicerol obteniendo el mayor valor (7.45 g·L-1). Se concluye que en la región existen cepas de levaduras nS con potencial enológico para ser utilizadas a nivel comercial.

Yellowfin tuna has a high level of free histidine in their muscle, which can lead to histamine formation by microorganisms if temperature abuse occurs during handling and further processing. The objective of this study was to measure levels of histamine in damaged and undamaged thawed muscle to determine the effect of physical damage on the microbial count and histamine formation during the initial steps of canning processing and to isolate and identify the main histamine-forming microorganisms present in the flesh of yellowfin tuna. Total mesophilic and psicrophilic microorganisms were determined using the standard plate method. The presence of histamine-forming microorganisms was determined in a modified Niven's agar. Strains were further identified using the API 20E kit for enterobacteriaceae and Gram-negative bacilli. Physically damaged tuna did not show higher microbiological contamination than that of undamaged muscle tuna. The most active histamine-forming microorganism present in tuna flesh was Morganella morganii. Other decarboxylating microorganisms present were Enterobacter agglomerans and Enterobacter cloacae. Physical damage of tune during catching and handling did not increase the level of histamine or the amount of microorganisms present in tuna meat during frozen transportation, but they showed a higher risk of histamine-forming microorganism growth during processing.

The use of microbial biofertilizers based on plant-growth-promoting rhizobacteria is a biotechnological alternative to improve production of horticultural crops seedlings. In this study, four bacterial strains previously isolated from tomato (Lycopersicum esculentum Mill.) rhizosphere were identified by using 16S rRNA gene sequence analysis and characterized according to their biochemical properties as plant growth promoters, and their effect on seed germination and seedling growth of tomato and bell pepper (Capsicum annuum L.) was also evaluated. The four strains isolated, named MA04, MA06, MA12 and MA17 and belonging to genus Bacillus, were able to produce indole acetic acid (0.9 to 2.3 mg L-1), to solubilize tricalcium phosphate (18.5 to 34.7 mg L-1), and posess ACC deaminase activity. Furthermore, MA04, MA06 and MA12 can grow in nitrogen free culture medium (with potential atmospheric nitrogen fixing ability). As far as their effect on tomato seeds, MA04 and MA17 improved germination by 5 and 6 % respectively, while MA06 and MA12 strains increased seedling weight by 17 and 20 %, respectively. On pepper seeds, only MA06 increased germination by 7 %, whereas MA12 and MA17 strains increased biomass by 37 and 16 % respectively. The MA12 strain proved to be the most efficient for improving seedling growth of tomato and bell pepper and could be proposed to produce biofertilizers for both plant species.

El empleo de biofertilizantes con base en rizobacterias promotoras del crecimiento, constituye una alternativa biotecnológica para mejorar la producción de especies de interés hortícola. En el presente trabajo se identificaron mediante análisis del gen 16S rRNA, cuatro rizobacterias previamente aisladas de plantas de tomate (Lycopersicum esculentum Mill.), las que fueron caracterizadas por sus propiedades bioquímicas relacionadas con la promoción del crecimiento vegetal y evaluadas por su efecto en la germinación y crecimiento de plántulas de tomate y pimiento (Capsicum annuum L.). Las cuatro cepas, denominadas MA04, MA06, MA12 y MA17, pertenecen al género Bacillus, producen ácido indolacético (0.9 a 2.3 mg L-1), solubilizan fósfato tricálcico (18.5 a 34.7 mg-L-1) y poseen actividad ACC deaminasa. Además, MA04, MA06 y MA12 fueron capaces de crecer en ausencia de nitrógeno (potenciales fijadoras de nitrógeno atmosférico). Al evaluar el efecto de la inoculación de estas rizobacterias en semillas de tomate se encontró que MA04 y MA17 aumentaron el porcentaje de germinación en 5 y 6 % respectivamente, mientras que las cepas MA06 y MA12 incrementaron el peso de las plántulas en 17 y 20 % respectivamente. En semillas de pimiento, la cepa MA06 incrementó el porcentaje de germinación en 7 %, y MA12 y MA17 incrementaron la biomasa en 37 y 16 %, respectivamente. La cepa MA12 fue más versátil para promover el crecimiento de plántulas de tomate y pimiento, y podría recomendarse para la formulación de biofertilizantes destinados al tratamiento de tales cultivos.

El agua de cola es un efluente complejo compuesto por una gran variedad de sólidos, los cuales deben ser removidos en su mayor parte para generar un efluente que pueda ser vertido directamente al mar. En el presente estudio el agua de cola se centrifugó y posteriormente se trató con quitosano a distintos valores de pH y concentraciones con la finalidad de remover sólidos presentes. Mediante la centrifugación se logró remover el 33,88% de los sólidos totales; 28,52% de proteína; 97,50% de grasa; 40% de ceniza y 20% de NNP, y disminuyeron la DBO5 y la DQO en un 42,2 y 63,3% respectivamente. El porcentaje de transmitancia aumentó de 14,6 a 18,4 siendo éste un cambio pequeño en relación al contenido de sólidos removido. La adición de quitosano al agua de cola centrifugada redujo en 25% el contenido de sólidos totales, 55% el de proteína, 40% el de grasa, 24% el de cenizas y 60% el de NNP. De igual forma, disminuyó la DBO5 y la DQO en un 48,4 y 31,2% respectivamente. Como resultado de la adición el porcentaje de transmitancia aumentó de 18,4 a 86,0; indicando que tal aumento se debió principalmente a la remoción de pigmentos y no de materia orgánica. Se logró una disminución importante en DBO5 y DQO; sin embargo, se requieren otras herramientas para reducir estos valores a concentraciones establecidas en la reglamentación sanitaria.

The stickwater is a complex effluent consisting of a variety of solids, most of which should be removed to produce a new effluent that can be directly poured into the sea. In this study, stickwater was centrifuged to remove solids and the resulting liquid was then treated with chitosan at different concentrations and pH to eliminate the solids left in it. Centrifugation extracted 33.88% of total solids, 28.52% protein, 97.50% fat, 40% ash and 20% NPN. It also decreased in 42.2 and 63.3% the BOD5 and COD, respectively. Transmittance percent increased from 14.6 to 18.4, a small change in relation to the content of solids removed. The addition of chitosan to centrifuged stickwater decreased 25% of the total solids content, 55% of protein, 40% fat, 24% ash and 60% NPN. Likewise, the addition of chitosan decreased the BOD5 and COD in 48.4 and 31.2%, respectively. As a consequence, transmittance increased from 18.4 to 86.0%, indicating that such increase was mainly due to the elimination of pigments rather than organic matter. A significant decrease was achieved in BOD5 and COD; nevertheless, other tools are required to reduce these figures to the levels established by the environmental health regulations.

O residuo liquido (stickwater) é un efluente complexo composto por uma grande variedade de sólidos, os quais deven ser removidos principalmente para gerar un efluente que possa ser vertido diretamente ao mar. No presente estudo o residuo líquido foi centrifugado e posteriormente tratado com quitosana a distintos valores de pH e concentrações com a finalidade de remover sólidos presentes. Mediante a centrifugación se conseguiu remover 33,88% dos sólidos totais; 28,52% de proteína; 97,50% de gordura; 40% de cinza e 20% de NNP, e diminuiram a DBO5 e a DQO em 42,2 e 63,3% respectivamente. A porcentagem de transmitância aumentou de 14,6 a 18,4 sendo esta uma mudança pequena em relação ao conteúdo de sólidos removido. A adição de quitosana no residuo líquido centrifugado reduziu em 25% o conteúdo de sólidos totais, 55% o de proteína, 40% o de gordura, 24% o de cinzas e 60% o de NNP. De igual forma, diminuiu a DBO e a DQO em 48,4 y 31,2% respectivamente. Como resultado da adição, a porcentagem de transmitância aumentou de 18,4 a 86,0; indicando que tal aumento foi devido principalmente à remoção de pigmentos e não de matéria orgânica. Alcançou-se uma diminuição importante em DBO5 e DQO; no entanto, são requeridas outras ferramentas para reduzir estes valores a concentrações estabelecidas na regulamentação sanitária.