Determinación de residuos de tetraciclina en carne de cerdos beneficiados en dos camales de Lima (2018)

El objetivo del estudio fue determinar la presencia de residuos de tetraciclina en la carne de cerdo en dos camales de Lima durante 2018. Se procesaron 25 g de carne del cuello de 402 cerdos beneficiados. Las muestras fueron obtenidas en la etapa de oreo y se evaluó mediante la técnica microbiológica de difusión enfrentando las muestras a la cepa de Bacillus subtilis ATCC 6633. Posteriormente se confirmó la presencia de tetraciclina mediante la técnica de ELISA MaxSignal Tetracycline Test Kit. No se encontraron muestras positivas a la prueba microbiológica de difusión. El 7.32% (6/82) resultó positiva a una concentración de tetraciclina entre 1587 y 5811 ppb. Ninguna de las muestras positivas superó los límites permitidos en el país.

Rapid sanitary and technological control of culturing the producers of amylolytic enzymes.

It has been established that the biotechnological process of culturing bacillary microbial producers of amylolytic enzymes can be express-controlled by determining their ATP bioluminescence. The advantages of the method have been shown. The analytical review of producers of hydrolytic enzymes has made it clear how practical it is to use bacillary microorganisms for targeted secretion of amylolytic enzymes in biotechnological production. After monitoring bacillary microorganisms, it has been found advisable to choose Bacillus subtilis ATCC 6633 as the working culture due to its time of production of amylolytic enzymes and its biosynthetic activity. Reasons have been given for using the rapid ATP control method, which is based on the principle of bioluminescence. Different growth media have been compared and evaluated in order to intensify the quantitative biosynthetic activity of the microbial culture in the technological process of culturing bacillary microorganisms. The experiments have proved that growth media can be modified by introducing a number of carbohydrate–protein substrates as inducers of amylolytic complex gene expression. The latter manifests itself in the amylolytic activity accelerated by 12–24 hours, and causes an increase in the number of microorganisms (1.87–3.99 times as many as in the reference culture). Two methods of control (rapid bioluminescent and classic microbiological) have been used for correlative determination of the quantitative growth of Bacillus subtilis cells. Mathematical straight-line correlations have been obtained in a semilogarithmic system for the number of cells of the bacillary producer of the amylolytic enzyme complex. These correlations allow carrying out rapid control in a production environment. Along with the traditional rapid sanitary control in biotechnological production, which includes controlling the contamination of the equipment, personnel’s hands, and water, it has been suggested to perform proprietary technological express control of amylolytic enzyme biosynthesis using the culture Bacillus subtilis ATCC 6633

APLIKASI BIOSURFAKTAN Bacillus subtilis ATCC 19659 DENGAN MEDIA PRODUKSI LIMBAH TAHU UNTUK ENHACED OIL RECOVERY

Biosurfactant as secondary metabolit produced by Bacillus subtilis. It has the ability to emulsify and reduce the surface tension. Biosurfactants produced by B. subtilis is a lipopeptide. Furthermore, biosurfactant can be utilized in microbial enhanced oil recovery (MEOR). In this research, biosurfactant of B. subtilis ATCC 19 659 were evaluated. The production use Nutrient Broth (NB) and soybean liquid waste. Application of biosurfactant in oil recovery showed that biosurfactant of NB recover 2 mL crude oil and biosurfactant of soybean liquid waste medium recover 3.67 mL.

Antimicrobial activities of different parts of two geographically distinct varieties of Jatropha curcas Linn. fruit in Pakistan

Antimicrobial activities of deoiled seed kernel (mechanically pressed), fruit coat and seed coat of Jatropha curcas Linn. collected from two regions (Bannu and Peshawar) of Pakistan were investigated. The antimicrobial activities were carried out against Klebsiella pneumoniae (ATCC 43816), Escherichia coli (ATCC 10536), Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633) and two clinical fungal isolates Aspergillus fumigatus and Candida albicans using agar well diffusion method. The antibacterial activities of Peshawar sample were found to be higher than Bannu, against selected strains. While antifungal activities of both samples were similar. Highest zone of inhibition 31.5 ± 0.7 mm was exhibited by n-hexane extract of deoiled seed kernel of Peshawar sample against Bacillus subtilis (ATCC 6633). The minimum inhibitory concentration of ethanolic extracts of deoiled seed kernel and seed coat of Peshawar sample was 31.25 - 25 mg/ml. Whereas, minimum inhibitory concentration of ethanolic and n-hexane extracts of Bannu sample was 62.5 - 125 mg/ml. The results suggested that antimicrobial potential of J. curcas Linn. varied with geographical distribution. The investigation of different varieties of medicinal plants belonging to the same species will greatly enhance the chances of best pharmaceuticals discovery. Bangladesh J. Bot. 50(2): 219-226, 2021 (June)

Multi-Scale Biosurfactant Production by Bacillus subtilis Using Tuna Fish Waste as Substrate

As one of the most effective biosurfactants reported to date, lipopeptides exhibit attractive surface and biological activities and have the great potential to serve as biocatalysts. Low yield, high cost of production, and purification hinder the large-scale applications of lipopeptides. Utilization of waste materials as low-cost substrates for the growth of biosurfactant producers has emerged as a feasible solution for economical biosurfactant production. In this study, fish peptone was generated through enzyme hydrolyzation of smashed tuna (Katsuwonus pelamis). Biosurfactant (mainly surfactin) production by Bacillus subtilis ATCC 21332 was further evaluated and optimized using the generated fish peptone as a comprehensive substrate. The optimized production conduction was continuously assessed in a 7 L batch-scale and 100 L pilot-scale fermenter, exploring the possibility for a large-scale surfactin production. The results showed that Bacillus subtilis ATCC 21332 could effectively use the fish waste peptones for surfactin production. The highest surfactin productivity achieved in the pilot-scale experiments was 274 mg/L. The experimental results shed light on the further production of surfactins at scales using fish wastes as an economical substrate.

Determinación de residuos de antibióticos en músculo, hígado y riñón de cuyes comercializados en cuatro ciudades del Perú

El objetivo del presente estudio fue determinar la presencia de antibióticos en hígado, riñón y músculo de cuyes de crianza intensiva en cuatro ciudades del Perú. Para ello, se evaluaron 410 muestras de carcasas, evaluando el hígado, riñón y músculo de cada carcasa. Las muestras fueron tomadas en la etapa de oreo en expendio y remitidas al laboratorio a 4 °C. La técnica utilizada fue la microbiológica de difusión en agar con la cepa Bacillus subtilis ATCC 6633 como cepa sensible; así mismo, se utilizó como control positivo un disco comercial de enrofloxacina de 5 µg de potencia. Las placas fueron incubadas a 37 °C durante 24 horas y luego se midió el diámetro de las zonas de inhibición de crecimiento bacteriana, con la regla de Kirby-Bauer. Se obtuvo frecuencias de halos de inhibición al crecimiento bacteriano de 28.54 + 4.37% (117/410) en muestras de riñón, de 27.07 + 4.3% (111/410) en músculo, y de 26.59 + 4.28% (109/410) en hígado. El estudio demuestra una elevada frecuencia de antibióticos en músculo, hígado y riñón de carcasa de cuy en expendio para el consumo humano en tres de cuatro ciudades del Perú.

EFFECT OF PLANT EXTRACTS ON BACTERIAL GROWTH AND POTENTIAL MECHANISM OF ACTION

Mentha piperita and Melissa officinalis are both well-known medicinal plants that have applications in traditional medicine. In this research the antibacterial activity of the ethanol extracts of M. piperita and M. officinalis was examined against 14 bacterial strains via the microdilution method. Minimum inhibitory concentrations of ethanol extracts of both plant species ranged from 0.312 to 20 mg/mL. Standard strains of Staphylococcus aureus ATCC 25923 at a concentration of 0.312 mg/mL and Bacillus subtilis ATCC 6633 at a concentration of 1.25 mg/mL showed the highest sensitivity to the ethanol extract of M. piperita. Ethanol extract of M. officinalis showed antibacterial activity on standard strains of S. aureus ATCC 25923 and B. subtilis ATCC 6633 at a concentration of 0.625 mg/mL. In addition to the mentioned standard strains, it showed activity on the isolate from the food Proteus spp. at a concentration of 0.312 mg/mL and isolate from the wound Proteus mirabilis at a concentration of 0.625 mg/mL. Mechanism of action of the ethanol extract of M. officinalis was examined on the permeability of the bacterial cell membrane. The effect of the extract on the increased permeability of the cell membrane was measured based on the release of proteins and the percentage of crystal violet binding. Ethanol extract of M. officinalis has been shown to act at the level of the cell membrane in the following bacterial strains of Pseudomonas aeruginosa, S. aureus and Enterococcus spp.

Rizobacterias con potencial antagonista in vitro a Mycosphaerella fijiensis Morelet

El empleo de bio-controladores en la agricultura beneficia los aspectos fisiológicos en plantas, a diferencia de la constante aplicación de pesticidas en el cultivo del banano ha ocasionado la pérdida de la sensibilidad en M. fijiensis, reduciendo la microbiota del suelo. El objetivo se enfocó en caracterizar el potencial antagónico de las PGPR en inhibición de germinación de ascósporas y desarrollo micelial de M. fijiensis. Se realizaron cultivos monospóricos de M. fijiensis e identificado por PCR. Se evaluaron los extractos celulares de Pseudomonas putida PB3-6, Klebsiella variicola BO3-4, Enterobacter asburiae BA4-19, Serratia marcescens PM3-8, Enterobacter asburiae PM3-14, Pseudomonas protegens CHA0, Pseudomonas fluorescens WCS417, Pseudomonas veronii R4 y Bacillus subtilis ATCC 5540 para sus evaluaciones antagonistas: a) Inhibición del tubo germinativo de las ascósporas al 2% y b) Desarrollo micelial al (2 y 10 %). La PCR empleado en la identificación de M. fijiensis se confirma el producto de amplificación de 1018 pb. El factor antagónico de los extractos celulares al 2 % de PM3-14 y CHA0 inhibe sobre el 80 % al desarrollo de los tubos germinativos. La inhibición al desarrollo micelial del extracto celular al 2 %, de CHA0 logró una efectividad del 54 % y las cepas (PM3-8, PM3-14 y BA4-19) con (32, 26 y 26 %). Al 10 % del extracto de la cepa PM3-8 inhibe el desarrollo micelial con niveles de turbidez de 0,47 (OD600nm). El empleo de estos bio-controladores en la agricultura ofrecerá una alternativa para beneficiar en la reducción del uso de agroquímicos

PHÂN LẬP SÀNG LỌC TUYỂN CHỌN CHỦNG VI SINH VẬT CÓ KHẢ NĂNG PHÂN HỦY NHỰA POLYETYLEN

Việc sử dụng polyetylen đang tăng lên theo thời gian và việc phân hủy nó đang trở thành một thách thức lớn. hàng năm, khoảng 500 tỉ đến 1000 tỉ túi nhựa được tiêu thụ trên toàn cầu. Nghiên cứu này nhằm mục đích phân lập sàng lọc tuyển chọn chủng vi sinh vật có khả năng phân hủy nhựa polyetylen. Nghiên cứu tiến hành phân lập và thu thập chủng chuẩn, từ 25 chủng vi sinh vật có khả năng phân hủy PE, qua sàng lọc và định danh đã tuyển chọn được 3 chủng là Bacillus drentensis (chủng phân lập), Bacillus subtilis ATCC 5230, Aspergillus oryzae ATCC 10124 có tiềm năng phân hủy PE. Các kết quả khảo sát về khả năng giảm trọng lượng PE (48,8%); khoảng cách PE cách bề mặt môi trường; độ bền kéo; sự thay đổi FTIR và thay đổi cấu trúc bề mặt PE (SEM) đã chứng minh khả năng phân hủy PE của chủng an toàn ưu thế nhất là Bacillus drentensis. Nghiên cứu cũng kiến nghị cần khảo sát với các chủng ứng viên hiện đang bảo quản trong bộ sưu tập.