In the present study, from a total of 100 strains isolated from waste vegetable oil contaminated soil, 38 bacterial and 14 fungi strains that presented positive lipolytic activity were obtained by detection through Rhodamine B Agar 0.02% w/v as a screening method. Additionally, two other enzymatic activities were determined. Positive proteolytic activity was evaluated in Casein Hydrolysis Agar and chitinolytic activity was identified by change in coloration in Bromocresol Purple Agar. Using these methodologies, we were able to report 18 microorganisms with two enzymatic activities and 6 microorganisms with all three enzymatic activities, thereby establishing these techniques as suitable and fast approaches for detection and semi-quantification of extracellular enzymatic activity.

The increasing use of alternative energy sources has brought benefits like the recycling of waste vegetable oils (WVO) for biodiesel production; however, this practice presents challenges derived from a highly variable raw matter. Our research focused on the washing techniques usually employed by small to medium scale producers which may lack the infrastructure to perform high-grade purification and often relay on the employment of “artisanal” technology. We report biodiesel production from pure canola oil (C1) and a mix of soybean/canola oil (C2) as well as WVO from sample C2 with high free fatty acid content (2.7 FFA %) oil. We selected seven quality tests: pH determination, cloud, pour and flash point, acid number (AN), water/sediments and soap content considering the most commonly failed checkpoints in biodiesel production. From the use of four washing techniques, we determined that the sawdust filtration had the highest recovering yield with 89%. The majority of the washed biodiesel met the America Society of Testing Material (ASTM) standard limits for the tests selected. Biodiesel stability was tested from week 0 to week 6, determining a shelf life of three weeks in optimal conditions without the addition of antioxidants or specific storage conditions.

In this work, we present the results of an undergrad student from the perspective of its first approach as a principal researcher in a project. In order to gain practical experience, one of the options for students that have interest in pursuing a postgraduate program corresponds to a research stay in a laboratory of their selected field conducting a project for a period of 6 months. In this particular project, a fungal sample was isolated from Parmesan cheese spoilage and its enzymatic activity evaluated. Using simple and standardized protocols, the student was capable of identifying a possible biotechnological application for the isolate by detecting and categorizing the lipolytic activity. Through microculture characterization in potato dextrose agar (PDA) the genus of the sample was determined as Penicillium and confirmed by molecular analysis of the ITS1 and ITS4 regions. In order to examine comprehensively the potential of the new isolate, the extracellular and intracellular enzymatic activities were analyzed as well as four methods of cell rupture. From these results, sonication was determined as the best technique with 211 U/L as a maximum lipolytic value. To finalize the evaluation of the sample, the student determined the optimal pH and temperature as well as the thermotolerance of the crude extract obtaining a residual activity of 13% after 60 minutes of incubation at 45 °C. Upon conclusion of the research we could recognize that through a direct characterization of a fungal isolate using techniques that are widely known, the student was capable of determining and value one of the most interesting capabilities fungi has to offer; enzymatic activity, and that the knowledge obtained from established protocols enables and encourages the students to correlate the source from where they were obtained with potential biotechnological applications. © 2019 International Union of Biochemistry and Molecular Biology, 47(6):681–688, 2019.

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