Instituto Tecnológico de Boca del Río

The final products of the ethanol industry are alcoholic beverages, industrial ethanol and biofuels. They are produced by the same production process, which includes fermentation and distillation of raw materials which come from plant biomass. At the end of the distillation process a waste effluent is obtained called vinasse or stillage. The direct disposal of stillages on land or in groundwater (rivers, streams or lakes), or even for the direct irrigation of crops, pollutes the environment due to their high organic contents, dissolved solids and many other compounds which are toxic or could be contaminants under certain environmental conditions. This work reviews the characterization of vinasses from different feedstock sources and the main treatments for conditioning the soluble solids of vinasses before their disposal.

BACKGROUND: A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. RESULTS: The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. CONCLUSIONS: The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production.Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production.

Cadmium is a major heavy metal found in polluted aquatic environments, mainly derived from industrial production processes. We evaluated the biosorption of solubilized Cd2+ using the extracellular polymeric substances (EPS) produced by Bacillus sp. MC3B-22 and Microbacterium sp. MC3B-10 (Microbactan); these bacteria were originally isolated from intertidal biofilms off the coast of Campeche, Mexico. EPS were incubated with different concentrations of cadmium in ultrapure water. Residual Cd2+ concentrations were determined by Inductive Coupled Plasma-Optic Emission Spectrometry and the maximum sorption capacity (Qmax) was calculated according to the Langmuir model. EPS were characterized by X-ray photoelectron spectroscopy (XPS) before and after sorption. The Qmax of Cd2+ was 97 mg g−1 for Microbactan and 141 mg g−1 for MC3B-22 EPS, these adsorption levels being significantly higher than previously reported for other microbial EPS. In addition, XPS analysis revealed changes in structure of EPS after biosorption and showed that amino functional groups contributed to the binding of Cd2+, unlike other studies that show the carbohydrate fraction is responsible for this activity. This work expands the current view of bacterial species capable of synthesizing EPS with biosorbent potential for cadmium and provides evidence that different chemical moieties, other than carbohydrates, participate in this process.

The effect of different feed rations on the productive performance and bacterial composition of the intestine of Nile tilapia (Oreochromis niloticus) reared using biofloc technology (BFT), in addition to water quality and the bacterial composition of the biofloc, was evaluated. During a 4-month period, five feed rations were evaluated: B-100, complete feed ration; B-90, 10% reduction; B-80, 20% reduction; B-70, 30% reduction; and B-60, 40% reduction, and a control group (C) supplied with clean water and a full feed ration. Each treatment was evaluated in triplicate. Fish were stocked into 18 circular tanks (3.14 m3) at a density of 50 tilapia/m3 per tank. At the end of the study, water samples and sections of fish intestine were taken. Colony-forming units (CFU) were counted on a plaque, and bacterial identification was carried out using the polymerase chain reaction, amplifying the 16S rRNA gene. All treatments exhibited good water quality throughout the study. Seventeen different species of bacteria were encountered in water and 15 species of bacteria were identified in the intestine of the tilapias. Treatments B-70 and B-60 were exhibited the highest number of bacteria recorded in water and intestine. The productive performance of Nile tilapia of treatment groups B-100, B-90, and B-80 was similar to C. The results indicate that during tilapia cultivation using BFT, it is possible to reduce the feed ration by 20% without apparent damage to the health and productive performance of Nile tilapia. The bacteria contribute to the maintenance of growth and survival of Nile tilapia by acting as a probiotic.

An important objective of aquatic ecotoxicology is to determine the effects of toxic compounds in organisms that play a central role in aquatic communities where rotifers have a large impact on several important ecological processes. The contribution of the rotifers to secondary production in many aquatic communities is substantial as they are often the larger fraction of zooplankton biomass at certain times of the year. In addition to the importance of their ecological roles in aquatic communities, the rotifers are attractive organisms for ecotoxicological studies by its short life cycles and rapid reproduction, their small size, and little volumes needed for culture and toxicity assays. The main end points used in ecotoxicological studies are mortality, reproduction, behavior, and biomarkers. Such parameters are included in international regulations from all over the world, where different species are used to evaluate the effect of environmental samples or chemical compounds. The high diversity of rotifers is an important issue because it can modify their relative susceptibility to toxicants. Thus, more studies are needed to know the relations and mechanisms involved in clonal variation, sensitivity, and development, which can be all assessed by state-of-the-art procedures.

Water contamination is a consequence of human settlement, agricultural, silvicultural, and industrial activity in aregion. The nitrates and nitrites dissolved in groundwater are indirectly consumed by humans, where they causenegative health effects. Among the most commonly observed problems are the dysfunction of the thyroid gland,production of nitrosamines (which commonly cause cancer), and a decrease in the capacity of the blood totransport oxygen, also known as metahemoglobinemia or,

Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS) synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured species, removing waste and contributing to the hygiene of closed systems. As ubiquitous components of coastal microbial habitats at the air–seawater and seawater–sediment interfaces as well as of biofilms and microbial aggregates, EPS mediate deleterious processes that affect the performance and productivity of aquaculture facilities, including biofouling of marine cages, bioaccumulation and transport of pollutants. These biomolecules may also contribute to the persistence of harmful algal blooms (HABs) and their impact on cultured species. EPS may also exert a positive influence on aquaculture activity by enhancing the settling of aquaculturally valuable larvae and treating wastes in bioflocculation processes. EPS display properties that may have biotechnological applications in the aquaculture industry as antiviral agents and immunostimulants and as a novel source of antifouling bioproducts.

Organochlorine pesticides are used in agricultural areas and health campaigns, which reach the coastal environment through rivers, drains, runoffs, and atmospheric transport. In aquatic environments, they are adsorbed by particles of organic matter, depositing themselves in sediments in the bottom of these bodies, in which benthic organisms of commercial interest for human consumption inhabit. The objective of this research was to evaluate the concentration of organochlorine pesticides in sediment from the Alvarado lagoon system in Veracruz, Mexico. In 20 out of 41 sampling sites analyzed, 11 banned organochlorine pesticides were identified, such as hexachlorocyclohexane (HCH), lindane, aldrin, dieldrin, and endrin. The highest concentrations were as follows: aldrin: 46.05 ng g−1; β-HCH: 42.11 ng g−1; α-HCH: 38.44 ng g−1; gamma γ-HCH (lindane): 34.20 ng g−1; δ-HCH: 31.61 ng g−1; methoxychlor: 29.40 ng g−1; heptachlor epoxide: 25.70 ng g−1; heptachlor: 24.11 ng g−1; dieldrin: 22.13 ng g−1; endrin: 21.23 ng g−1; endrin aldehyde: 12.40 ng g−1. Concentrations reported are prohibited in international standards. There is a strong need to further evaluate, with scientific studies, the level of concentration reported by impact of compounds widely used in agricultural livestock activities.

Abstract Aquaculture practice in Mexico is commonly carried out with some freshwater species, which are introduced in the region for its production, with technology developed in other countries. The growth of this activity has been slow, sometimes leading to loss of investments due to difficulties in the implementation of foreign technological packages, poor selection and inadequate management of the species, or farming sites, and even confusing legal procedures. Mexico stands out for the development of crops of exotic species more than native species, of which most are freshwater type. There are thirty‐four recorded species of freshwater fish, six of them are native and twenty‐eight are introduced species. The success of cultivating native species lies mainly in the process of selecting species with potential and certain characteristics. Mariculture is relatively new in Mexico; it has been intensibly developed, mostly in the north‐west of the country. It has a great potential due to the high commercial value of its species, excellent quality and demand in the market. Ornamental aquaculture is the most developed in Mexico; the main producer is the state of Morelos, with total technological expertise in production of introduced and native species. It should be noted that this success has been achieved, in some cases, with the support of projects from government institutions, universities, research centres, associations and private companies. Pointing out that the common factor for a successful aquaculture practice is an ecosystemic and sustainable approach, continuously improving practices and fish farming management, while complying with regulatory standards.

The compensatory growth, productive performance, proximal composition and somatic indices of Nile tilapia (Oreochromis niloticus) cultivated in biofloc were evaluated during a 144-day period under five cyclic regimes of feed restriction and feeding. Five treatment groups, in which the frequency of feed restriction (R) and feeding (F) varied by periods (days) as follows: R1:F3, R3:F9, R6:F18, R8:F24 and R12:F36; each treatment was evaluated in triplicate. The cycles were repeated throughout the culture period. The control group received feed daily. Fish were cultivated in 18 circular tanks (3 m3) at a density of 50 fish/m3 per tank. At the end of the study, the survival of Nile tilapia was greater than 90% in all the treatments. Complete compensation in growth was achieved in R6:F18 and R12:F36. At the end of the feed restriction period, both crude protein and total lipid content of the tilapia muscle tissue taken from fish of the treatment groups were similar to samples of muscle tissue derived from fish of the control group; however, a reduction of more than 40% in somatic indices compared with the control was observed, but these recovered by the end of the feeding phase. The results indicate that cyclic feeding based on 12 days of feed restriction and 36 days of feeding (R12:F36) induced a complete compensation in weight and restoration of energy reserves, with similar measures of productive performance observed when compared to the control treatment during the culture of Nile tilapia in biofloc, and food reduction did not affect proximal composition.

Se analizan los sistemas de producción acuícolas mexicanos en las áreas del Océano Pacífico, Golfo de México y Mar Caribe. Las especies que se desarrollan en cultivos acuícolas son: ostras (Crassostrea gigas, Crassostrea corteziensis), abulón (Haliotis fulgens, Haliotis rufescens), almeja, (Panopea generosa), camarón (Litopenaeus vannamei), langostino (Macrobachium rosenbergii), túnidos (Thunnus thynnus), tilapia (Oreochromis niloticus), carpa (Cyprinus carpio), trucha (Oncorhynchus mykiss), bagre (Ictalurus punctatus) y lobina (Micropterus salmoides). Otras especies que se obtienen por medio de la captura, son las utilizadas para su desarrollo en sistemas de producción acuícolas. En la región sur del Golfo de México del total de las unidades de producción acuícolas (UPA), el 62% se tienen identificadas como unidades que se dedican a la engorda de tilapia y el 38% a su engorda y reproducción. Lo anterior es un riesgo y puede incrementar el impacto en los ecosistemas acuáticos por los efluentes que se generan por estas actividades acuícolas ya que contienen diferentes componentes, entre los que destacan materia orgánica, nitrógeno y fósforo. Hay diferentes estudios para el tratamiento de estos efluentes, pero son poco aplicados a escala real, ya que son realizados a nivel de laboratorio. Se requiere obtener y aplicar tecnología funcional para los productores de unidades de producción acuícolas con el objetivo de evitar el impacto a los ecosistemas, principalmente los riesgos químicos y biológicos al medio acuático.

During a growout period of 14 weeks, the productive performance, organosomatic indices and body composition of the Nile tilapia Oreochromis niloticus cultivated at high density reusing the water from systems with biofloc technology (BFT) were evaluated. Two treatments: tilapia cultured in biofloc (TB) and tilapia cultured in reused water biofloc (RW) were established. Mixed sex, juvenile Nile tilapia (average weight and length: 79.28 ± 14.44 g and 12.44 ± 0.70 cm) were stocked into 6 experimental units (0.2 m3) at a density of 100 fish/m3. Temperature, dissolved oxygen, total dissolved salts, pH, NH4–N, NH3–N and NO3–N were recorded daily, while NO2–N, general hardness, carbonate hardness and settleable solids were recorded weekly. The weight and length of the tilapias were recorded biweekly. Survival, productive performance, proximal composition and organosomatic indices of Nile tilapia were evaluated. The water parameters in RW treatment such as pH, total dissolved salts, NO2–N, NO3–N and carbonate hardness were significantly greater (p < 0.05), when compared to those obtained in TB treatment. Survival rate was > 98% under both treatments. The final weight (TB = 163.09 ± 42.34 g, RW = 159.23 ± 39.92 g), protein (19.1%) and lipid (2.2%) content of the tilapia were non-significantly different between treatments. In addition, no significant differences in the gonadosomatic and hepatosomatic indices were observed either between tilapia sex or between the treatments. The results suggest that the intensive cultivation of Nile tilapia in biofloc can be established using reuse water from BFT systems, without adverse effects on their survival, productive performance, proximal composition and gonadal development.

The fluvial–lagoon–deltaic system of the Palizada River in Campeche is an ecosystem of socioeconomic and ecological importance. It is justifiable to carry out studies in this system due to its connection with another larger ecosystem called the Términos Lagoon. The objective of this investigation was to analyze the concentration of Pb and Cd in sediments of the fluvial–lagoon–deltaic system of the Palizada River and to determine, with this, the contamination index of these metals. Cd showed the highest concentration in sampling sites and climatic seasons with respect to Pb, with a maximum value of 53.9 ± 5.0, while the Pb concentration was 10.4 ± 0.2 μg∙g−1. The same tendency was present with pollution and geoaccumulation indexes; here, the Cd index stands out. The enrichment of heavy metals was identified through the accumulation of Cd and Pb; such a process was evaluated through the geoacumulation index (Igeo). The results of this indicated that the contamination of these elements is mainly of anthropogenic origin. This element represents an ecological toxic risk due to the chronic presence of heavy metals in a priority area for the conservation of aquatic and terrestrial biota such as the Palizada system, owing to its high toxicity even at low concentrations. Thus, it is important to evaluate its sublethal effects in the organisms that inhabit this system, which requires the implementation of integral monitoring.

The aquariums industry is a trade that is expanding. Although there is no accurate information regarding the figures of the aquarium industry in the international scenario, it is estimated to generate revenues over US$ 300 million with an annual growth rate of 14%. Approximately US$ 28 to 44 million of this amount is generated by the ornamental marine fish trade. However, the trade in marine species has aroused controversy regarding the extraction of almost all traded marine organisms from wild populations and, in many cases, illegally. This paper presents a review that includes: the ornamental marine fishkeeping history, the species of commercial importance, the international trade scenario, risks of the aquarium industry, conservation strategies, and the current situation of this trade in Mexico. The last section focuses on describing the development and market prospects of the marine aquarium trade. Additionally, some initiatives from academic and private institutions aimed at developing sustainable aquaculture on ornamental marine fish species of commercial importance in Mexico are provided.

Abstract Wood–plastic composites (WPCs) are considered to be highly durable materials and immune to any type of biological attack. However, when one of these composites is exposed to accelerated weathering, its surface is affected by the appearance of cracks, which constitute an ideal access route for biotic agents. Although the destruction of wood caused by termites is recognized worldwide, information on their effects on WPC‐based products is scarce. Thus, in this study, we aimed to examine the effects of termite attacks on weathered and nonweathered pinewood residue/recycled high‐density polyethylene composites. In this study, WPCs with 40 wt % wood were prepared. Test samples obtained by compression molding and profile extrusion were subjected to weathering cycles for 1000 and 2000 h with a UV‐type accelerated tester equipped with UVA‐340 fluorescent lamps. Afterward, specimens were exposed to the attack of higher termites ( Nasutitermes nigriceps ) native to the Yucatan Peninsula. Subsequently, flexural mechanical essays, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses were performed. FTIR spectroscopy and DSC showed that the surfaces of the compression‐molded specimens were degraded to a higher extent because of the accelerated weathering. The microscopy results revealed that severe damage was caused by the termites on the surface of the compression‐molded samples. Statistical analysis of the mechanical test results showed that biotic attack produced significant changes in the samples previously exposed to accelerated weathering. The results show that the processing method directly affected the sample performance because of differences in the surface composition. The profile‐extruded composites seemed to better resist termite attack. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Two studies were conducted in laboratory (E1 and E2) with clownfish juveniles Amphiprion ocellaris in which the survival, growth, body colour and total carotenoid content in the skin were evaluated. In E1, diets supplemented with one of three levels of lutein or astaxanthin (0.5%, 1% and 1.5%) were evaluated; and, subsequently, in E2, two background colours were used in the fish tanks (black/white), which included two different light spectrums (white/red). The survival and growth rate of the fish in both studies were similar irrespective of the treatment. The fish fed the diets supplemented with 0.5% and 1% astaxanthin (E1) exhibited an intense red pigment and a significantly superior (p < 0.05) total carotenoid concentration in skin compared to the other treatments. In E2, an intense red pigmentation and well-defined black bands were observed in fish kept in black background tanks, whereas fish kept in tanks with white background had a yellowish hue and barely visible bands. In contrast, the light spectra did not have an effect on body pigmentation. Based on the results, it was concluded that the body colour of the clownfish depends on the carotenoid source in the diet and the colour of the culture system rather than the light spectra. It is, therefore, recommended that a minimum of 0.5% astaxanthin is included in the diet and that the fish are kept in tanks with a black background, to maintain the intense red coloration that is characteristic of the species.

During a 100-day period, the effect of two background colours (white and black) of fish tanks and two light spectrum (red and white) on the growth and pigment expression of juvenile peppermint shrimp Lysmata wurdemanni was evaluated. A completely randomized experimental design was implemented with four treatment groups and a control group (natural illumination). At the end of the study, the survival, weight gain and total carotenoid content in the abdomen and cephalothorax (spectrophotometry) were evaluated, in addition to the expression of the body colour through the analysis of digital images (colour composition RGB). The survival, weight gain (%) and total carotenoid content in the abdomen of the shrimp were similar between treatment groups (p > 0.05); however, the pigment content in the cephalothorax of the shrimp of the black background/red light treatment and the control group were significantly greater (p < 0.05) compared to the carotenoid content of shrimp of the white background/white light treatment. Independently of the total carotenoid content and of the light spectra, the shrimp of the treatments that included black background colour expressed a greater body pigmentation in comparison with those preserved in tanks with white background. These data indicate that the shrimp have a constant concentration of body pigments which they express to a greater or lesser degree depending on the environmental conditions in which they live. This effect of environmental conditions on body pigmentation should be considered during the controlled maintenance and cultivation of the peppermint shrimp.

Effect of isolipidic (62.7 ± 5.0 g kg−1) diets with protein levels of 204.6 (T20), 302.3 (T30), 424.6 (T40) or 511.0 g kg−1 (T50) on growth and survival in Nile tilapia (Oreochromis niloticus Linnaeus 1758) fry cultured for 70 days at one of four salinities (0, 15, 20 and 25 g L−1) was evaluated. A bifactorial (4 × 4) design was used with 16 treatments run in triplicate and 20 fry (0.25 ± 0.04 g) per replicate under semi-controlled conditions. Four independent, recirculating systems (one per salinity level) were used, each one with 12 circular tanks (70 L capacity), filters and constant aeration. The different salinities had no significant effect on growth. Weight gain improved significantly as dietary protein content increased, although organisms fed the T50 diet had a lower growth rate. Survival was highest (98.33%) in the T50/15 (protein/salinity levels) treatment and lowest (71.0%) in the T20/20 treatment, with no pattern caused by the variables. The T40/25, T40/20 and T50/0 treatments produced the most efficient growth and feed utilization values while the T20 treatments at all the salinities resulted with the lowest performance. With the exception of the T50 treatments, a non-significant tendency to increased weight gain was observed as water salinity increased, suggesting that the salinity of the culture environment does not influence dietary protein requirements in Nile tilapia O. niloticus fry.

The use of herbicides to control weeds is a part of agricultural management throughout the world. Unfortunately, the indiscriminate use of these herbicides may have impacts on non-target organisms (Sarma et al., 2001; Nwani et al., 2010). The long persistence of many herbicides in freshwater suggests that they are capable of producing adverse effects on

The oyster fishery is 1 of the most important coastal fisheries in Mexico. Management is based on a minimum legal size of 80 mm and several seasonal bans that vary along the coast of the Gulf of Mexico. We describe the gonad development cycle of Crassostrea virginica (Gmelin 1791) along the Mexican coast of the Gulf of Mexico for 5 lagoons for the years 2000 and 2004, between latitudes 21°41′16.75″ N and 18°23′51.08″ N. Significant differences in duration and intensity were observed among reproductive stages associated with different environmental conditions. Gametogenesis and mature stages correlated positively with temperature and total chlorophyll, respectively. Spawning correlated negatively with salinity in both years. Maturity correlated positively with total chlorophyll levels. The reproductive stages varied from seasonal, a few months, to continuous throughout the year. Recovery, expressed as the number of organisms in postspawning and resting stages, was fast for populations that presented constant gametogenesis and spawning, with less than 50% of the population in postspawning and resting stages. Environmental fluctuations in total chlorophyll are the regulating factors for gametogenic activity, rather than latitudinal temperature variations. This makes monitoring environmental conditions in the lagoons or gonad development a necessity to predict reproduction and recruitment for proper management of the oyster resource.