Alkaline-Tolerant Bacillus cereus 12GS: A Promising Polyhydroxybutyrate (PHB) Producer Isolated from the North of Mexico.

Environmental pollution caused by petroleum-derived plastics continues to increase annually. Consequently, current research is interested in the search for eco-friendly bacterial polymers. The importance of Bacillus bacteria as producers of polyhydroxyalkanoates (PHAs) has been recognized because of their physiological and genetic qualities. In this study, twenty strains of Bacillus genus PHA producers were isolated. Production was initially evaluated qualitatively to screen the strains, and subsequently, the strain B12 or Bacillus sp. 12GS, with the highest production, was selected through liquid fermentation. Biochemical and molecular identification revealed it as a novel isolate of Bacillus cereus. Production optimization was carried out using the Taguchi methodology, determining the optimal parameters as 30 °C, pH 8, 150 rpm, and 4% inoculum, resulting in 87% and 1.91 g/L of polyhydroxybutyrate (PHB). Kinetic studies demonstrated a higher production within 48 h. The produced biopolymer was analyzed using Fourier-transform infrared spectroscopy (FTIR), confirming the production of short-chain-length (scl) polyhydroxyalkanoate, named PHB, and differential scanning calorimetry (DSC) analysis revealed thermal properties, making it a promising material for various applications. The novel B. cereus isolate exhibited a high %PHB, emphasizing the importance of bioprospecting, study, and characterization for strains with biotechnological potential.

Muffin-Type Bakery Product Based on Mexican Mesquite (Prosopis spp.) Flour: Texture Profile, Acceptability, and Physicochemical Properties.

In this research, muffin-type bakery products were developed based on wheat flour (WF) and mesquite flour (MF) in the following proportions: WFMF 90:10, WFMF 75:25, and WFMF 50:50. The products were characterized based on various properties in which it was possible to observe that the water activity (aw) did not show a significant change with the increase in the concentration of MF. In addition, the increase in the concentration of MF modified the sensory properties (color, odor, flavor, texture, and acceptance), further decreasing the luminosity and increasing the values of the a* and b* coordinates. Moreover, in the texture profile analysis, it was found that the increase in the MF concentration increased hardness, fracturability, and gumminess and decreased adhesiveness and cohesiveness. All the previously mentioned changes were more evident in the WFMF50:50 and, to a lesser degree, in WFMF75:25. In general, in most evaluations realized, the WFMF90:10 treatment was the most similar to the control (without MF). However, WFMMF75:25 provided a higher protein and fiber content and a lower fat content. Finally, it is possible to use the flour obtained from the mesquite fruit to make bakery products since it is an important source of food due to the wide distribution of mesquite in the country.

Draft Genome Sequence of a Polyhydroxyalkanoate-Producing Bacillus cereus Strain Isolated from Nuevo Leon State, Mexico.

Polyhydroxyalkanoates (PHA) are microbially produced biopolymers which are biodegradable and biocompatible. These compounds produced by microorganisms have been described as a potent alternative to synthetic plastics, which are often recalcitrant. Here, we report the draft genome sequence of a PHA-producing Bacillus cereus isolated in our laboratory.

Efficient recovery of thermostable polyhydroxybutyrate (PHB) by a rapid and solvent-free extraction protocol assisted by ultrasound.

Nowadays, there are great research interest in polyhydroxybutyrate (PHB) recovery protocols that reduce the use of organic solvents and efficiently recover this bacterial biopolymer. The present study reports an extraction protocol assisted by ultrasound, which is a rapid protocol that increases the amount of polymeric matter extracted, reduces the cellular digestion step with sodium hypochlorite and eliminates the use of organic solvents. Likewise, characterization studies by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) demonstrated that the biopolymer recovered by this protocol is PHB homopolymer with a major thermal-resistance and crystalline properties. Besides, in this study are reported the thermic and crystalline differences between the PHB obtained from the fermentation of complex carbohydrates (agavins) and simple sugars. The biopolymer obtained by this rapid extraction protocol would be suitable for ecological and biomedical applications, due to the low melting temperature, less than 50% crystallinity, and the lack of lipopolysaccharides. Therefore, this extraction protocol might represent an alternative to the traditional protocol based on NaOCl-chloroform and is part of the green trend to improve the PHB production.

Cr(VI) adsorption from aqueous solution by fungal bioremediation based using Rhizopus sp.

The highly toxic species of Chromium in its hexavalent state is an important hazard to the flora and fauna, causing a rupture in balance especially in aquatic environments. The removal of Cr(VI) ions from aqueous solutions using fungal biomass of Rhizopus sp. was investigated under batch experiments. The biomass was produced and treated with NaCl to compare pre-treated and untreated biosorbents capacity. Adsorption of Cr(VI) was investigated with a 23 experimental design to determine the best operational parameters including pH [2.0-4.0], temperature [20-40 °C] and agitation [50-150 rpm]. Maximum Cr(VI) uptake (99%) indicated that pH 2.0 is the optimal for Cr(VI) removal. Linear and non-linear kinetic models were evaluated. The best fitting for linear kinetics was the pseudo-second order linear equation and the Elovich model in its non-linear form, suggesting chemisorption as the controlling step of adsorption. Results followed Langmuir isotherm equation, the qm was 9.95 (mg·g-1) for Rhizopus sp. + NaCl. Thermodynamic parameters were calculated using the adsorption equilibrium constant obtained from Langmuir isotherm and indicated that the adsorption process was spontaneous and endothermic. The surface characteristics of the biomass were analyzed by Fourier transform infrared (FTIR) spectra; the analysis showed the involvement of amino groups in the bonding with Cr(VI). SEM and EDX analysis confirmed the presence of Cr in the biomass after adsorption. The results of these experiments may be utilized for modeling, simulation, and scale-up processes in the future.

Producción de unidades infectivas de Isaria fumosorosea (Hypocreales: Cordycipitaceae) a partir de aislados nativos del noreste de México mediante 3 estrategias de propagación / Production of infectious units of Isaria fumosorosea ( Hypocreales: Cordycipitaceae) from different indigenous isolates of northeastern Mexico using 3 propagation strategies

El objetivo del presente estudio fue evaluar la producción de blastosporas y conidios de diferentes aislados nativos de México del hongo entomopatógeno Isaria fumosorosea y de una cepa de colección mediante diferentes técnicas de propagación. En la producción de blastosporas se utilizaron 2 medios de cultivo líquidos (sumergidos), uno a base de casaminoácidos y el otro a base de peptona de colágeno como fuentes de nitrógeno, con glucosa como fuente de carbono en ambos. Para la producción de conidios, los hongos se cultivaron en agar papa dextrosa, a partir de esos cultivos se prepararon suspensiones de 1 x 10(6) conidios/ml para inocular matraces con caldo dextrosa Sabouraud, para iniciar así la fase líquida del cultivo bifásico, denominado también precultivo. Posteriormente con el precultivo y las suspensiones de conidios se inocularon bolsas con granos de arroz, que se incubaron durante 14 días para el cultivo bifásico y para la fermentación sólida, respectivamente. El aislado HIB-23 fue el que logró la más elevada concentración de blastosporas obtenida en el cultivo sumergido: 4,90 x 10(8) blastosporas/ml en el medio casaminoácidos; y en el medio con peptona de colágeno se obtuvieron 2,15 x 10(8) blastosporas/ml. La máxima producción de conidios en fermentación sólida la logró la cepa Pfr-612 (1,58 x 10(9) conidios/g), mientras que la máxima en cultivo bifásico correspondió al aislado HIB-30 (9,00 x 10(6) conidios/g). La fermentación sólida resultó ser el método más efectivo, con un promedio de 1,09 x 10(9) conidios/g, mientras que el cultivo bifásico fue el menos efectivo, con un promedio de 2,76 x 10(6) conidios/g. Para la producción de blastosporas en los medios sumergidos no se obtuvo diferencia significativa alguna.

The aim of this study was to evaluate the production of blastospores and conidia of different native isolates and a strain of Isaria fumosorosea using different propagation techniques. Two liquid culture media of casamino acids and peptone as nitrogen sources and glucose as carbon source for both media cultures were respectively used in the production of blastospores, while for the production of conidia, the fungi were grown in potato dextrose agar; from these cultures, solutions of conidia to a concentration of 1 x 10(6) per milliliter were prepared to inoculate flasks with Sabouraud dextrose broth for the liquid phase of the biphasic culture, also known as preculture. Subsequently, rice grain bags were inoculated with the preculture and the conidia solutions, which were incubated for 14 days for solid fermentation and biphasic culture, respectively. The HIB-23 isolate recorded a concentration of 4.90 x 10(8) blastospores/ml in the casamino acid medium, while a concentration of 2.15 x 10(8) blastospores/ml was obtained in the peptone collagen medium. For the Pfr-612 strain, the conidia production in solid-state fermentation was 1.58 x 10(9) conidia/g, and for HIB-30 in the biphasic culture of 9.00 x 10(6) conidia/g. Solid-state fermentation proved to be the most effective method with an average of 1.09 x 10(9) conidia/g, whereas the biphasic culture was the least effective method with 2.76 x 10(6) conidia/g; no significant difference was reported for the submerged production media.

[Production of infectious units of Isaria fumosorosea (Hypocreales: Cordycipitaceae) from different indigenous isolates of northeastern Mexico using 3 propagation strategies]. / Producción de unidades infectivas de Isaria fumosorosea (Hypocreales: Cordycipitaceae) a partir de aislados nativos del noreste de México mediante 3 estrategias de propagación.

The aim of this study was to evaluate the production of blastospores and conidia of different native isolates and a strain of Isaria fumosorosea using different propagation techniques. Two liquid culture media of casamino acids and peptone as nitrogen sources and glucose as carbon source for both media cultures were respectively used in the production of blastospores, while for the production of conidia, the fungi were grown in potato dextrose agar; from these cultures, solutions of conidia to a concentration of 1×106 per milliliter were prepared to inoculate flasks with Sabouraud dextrose broth for the liquid phase of the biphasic culture, also known as preculture. Subsequently, rice grain bags were inoculated with the preculture and the conidia solutions, which were incubated for 14 days for solid fermentation and biphasic culture, respectively. The HIB-23 isolate recorded a concentration of 4.90×108 blastospores/ml in the casamino acid medium, while a concentration of 2.15×108 blastospores/ml was obtained in the peptone collagen medium. For the Pfr-612 strain, the conidia production in solid-state fermentation was 1.58×109 conidia/g, and for HIB-30 in the biphasic culture of 9.00×106 conidia/g. Solid-state fermentation proved to be the most effective method with an average of 1.09×109 conidia/g, whereas the biphasic culture was the least effective method with 2.76×106 conidia/g; no significant difference was reported for the submerged production media.