Given the importance of protease’s worldwide market, the determination of optimum conditions and the development of a standard protocol are critical during selection of a reliable method to determine its bioactivity. This paper uses quality control theory to validate a modified version of a method proposed by Charney and Tomarelli in 1947. The results obtained showed that using azocasein substrate bromelain had its optimum at 45°C and pH 9 (Glycine-NaOH 100 mM). We also quantified the limit of detection (LoD) and limit of quantification (LoQ) in the above-mentioned optimum (0.072 and 0.494 mg·mL⁻¹of azocasein, resp.) and a calibration curve that correlates optical density with the amount of substrate digested. In all analysed samples, we observed a significant decrease in response after storage (around 17%), which suggests its use must be immediately after preparation. Thus, the protocol presented in this paper offers a significant improvement, given that subjective definitions are commonly used in the literature and this simple mathematical approach makes it clear and concise.

Microalgae are aquatic unicellular microorganisms that can be found both in freshwater and marine systems; are capable of photosynthesis; and can grow as individual cells or associated in chains or small colonies. Microalgae cultivation has gained large momentum among researchers in the past decades due to their ability to produce value metabolites, remarkable photosynthetic efficiency, and versatile nature. The wide technological potential, and thus increasing amount of scattered knowledge, may become the very first barrier that a post graduating student, or any non-specialist reader, will face when introduced to the subject. In this review paper, we access the core aspects of microalgae technology, covering their main characteristics, and comprehensively presenting the main features of their various cultivation modes and biological activity from metabolites.

Renewable energies are cleaner forms of energy, and their use, has intensified in recent decades. Thus, this work presents a proposal for reducing the emissions, fuel cost, and respiratory disease hospitalizations using environmental cost accounting principles to produce biodiesel production from waste frying oil. In our methodology, we conducted surveys, and collected waste cooking oil samples from local households and restaurants in São Paulo city, Brazil. Then, we produced biodiesel using these samples. Data on air pollutants were collected and correlated with the number of hospitalizations for respiratory diseases and their costs. Our results indicate that 330,000 respiratory disease hospitalizations were recorded in São Paulo city between 2009 and 2018, and the total cost for the Brazilian government reached US $117 million. Improving the city air quality by switching from fossil fuels to biodiesel could reduce the annual number of hospitalizations to 9880 and cost US $3.518 million, because the amount of pollutants emitted from burning fossil fuels was positively correlated with the number of respiratory disease hospitalizations and their costs. Moreover, the emission rates of particulate matter with particles less than 10 and 2.5 µm in diameter exceeded the World Health Organization limits throughout the study period. Using the survey data, we estimated that the average monthly quantity of waste cooking oil was 9794.6 m³, which could generate 9191.2 m³ of biodiesel and produce 239,713 t CO₂ of carbon credits. Environmental cost accounting revealed that it would be possible to achieve an annual profit of approximately US $300 million from the sale of excess biodiesel, carbon credits, and glycerine, and fuel acquisition savings which could improve the image of São Paulo city and quality of life of its residents. Thus, we present this as a way to reduce cost and hospitalizations, and increase the number of available hospital beds for other diseases, such as COVID-19.

L-asparaginase (L-ASNase) is the gold standard enzyme used to treat acute lymphoblastic leukemia. This disease primarily affects children; however, treatment increases survival from 20% to 90%. As a bioproduct, it is obtained via a biotechnological process and its purification usually consists of several steps that account for up to 80% of the total production costs. This review discusses available strategies for the purification of L-ASNase and highlights a process with fewer steps, and consequently, lower cost and higher yield. This process emphasizes the possibility of using a novel aqueous two-phase system extraction process to purify L-ASNase.

Microalgae have a high growth rate, high CO₂ absorption capacity, and high content of chlorophyll, proteins, vitamins, mineral salts, carbohydrates, antioxidant substances, and fatty acids. In recent years, Chlorella vulgaris has been widely used as a feedstock for producing third-generation biofuels, such as bioethanol. Thus, this work aims to develop a strategy to increase the production scale of the microalgae Chlorella vulgaris grown in distilled reused water, supplemented with a modified BG-11 medium, to use biomass in the production of bioethanol. The total cultivation of 72 L presented a concentration of 0.415 g·L⁻¹·d⁻¹, with 61.32 g of final biomass. To improve carbohydrate extraction, the biomass was pre-treated with sulfuric acid at different concentrations (1.5% and 3% v/v). The hydrolyzed solution was supplemented with YPD (yeast extract peptone dextrose) medium and inoculated with Saccharomyces cerevisae yeast, initiating fermentation. In each sample, the Brix degree, cell concentration, reducing sugar concentration, and alcohol content were analyzed. The sample pre-treated with sulfuric acid 1.5% v/v was the one that presented the best result, with alcohol content after distillation of 68 °GL (Gay-Lussac). It appears that the cultivation of the microalgae Chlorella vulgaris in scale-up, with reused water, has high potential in the production of third-generation biofuel.