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The coffee processing wastewater (CPWW) requires treatment before being disposed of in the environment or reused due to its high organic and inorganic composition and a low pH. The indigenous microbiota from CPWW is highly diverse and could be selected as inoculums in treatment waste plants. Considering the physico-chemical characteristics of wastewater coffee, we elaborate on steps to select the microbial consortium that showed positive impact via decreasing the pollutant parameters of this effluent. The effectiveness was confirmed using wastewater from different origins with different chemical characteristics. A bacterial consortium composed by Serratia marcescens CCMA 1010 and CCMA 1012, Corynebacterium flavescens CCMA 1006, and Acetobacter indonesiensis CCMA 1002 was selected as the inoculums-based phenotypic assays. The mixed inoculum showed a highly active population (11.18 log CFU mL-1), promoting an 85% decrease in biochemical oxygen demand and a 60% decrease in chemical oxygen demand. There was also an 80% reduction in phosphorus and nitrogen. The final pH changed from 6.0 to 7.5. Additionally, the eco-toxicity using Daphnia similis was reduced by more than 59%. The microbial inoculum was efficient in the biological treatment in CPWWs, demonstrating the efficiency and robustness of the selected strains, independent of the physico-chemical characteristics of wastewater.

Despite the undesirable effects of its byproducts, such as the formation of trihalomethanes, chlorination is the most widely used method of disinfection in the Wastewater Treatment Plants (WWTPs) worldwide. Therefore, besides reducing the labor cost of this treatment stage, the automatic product dosage as calcium hypochlorite may increase its efficiency, avoiding wastage and reducing its unwanted effects. To accomplish it, a digital controller needs to be constantly fed with information that allows it to estimate the disinfection potential of the process, which traditionally occurs by means of gauges that concomitantly appraise the Oxidation–Reduction Potential (ORP) and the pH of the water in analysis. In this work, the technique known as biospeckle laser was investigated as an alternative to support the measurements required for an automatic chlorination system, performing the correlation between the biological activity level and the presence/inactivation of pathogenic microorganisms in samples of water collected after the biological treatment stage of a WWTP. Five treatment groups were analyzed by 16 replications and the responses were consistent when compared with those obtained using standard methods for this sort of analysis, demonstrating that the investigated technique is feasible for the desired purpose, indicating if the disinfection is being satisfactory or not.

Dynamic laser speckle (DLS) technique or biospeckle is a noninvasive approach that can sensitively monitor the dynamics of a biological material such as the metabolism of cells. In turn, stimulation of cell activity is widely used in microbiology: it can be done by means of many agents, such as lipopolysaccharide (LPS), which is the most common component within the cell wall of Gram-negative bacteria, and it has been extensively used in in vitro models studying inflammation. The main challenge is to monitor the change of behavior inside the cells during their stimulation. This work tested the viability of the BSL to monitor the change in the metabolism of RAW cells when LPS is applied. The results show different answers of cells to distinct concentrations of LPS, and the inflammatory process promoted by the LPS could be best distinguished from the RAW cells alone in a concentration of 10 ng/mL. This proved the ability of the DLS to monitor the agent stimulus.

Dynamic laser speckle phenomenon allows a contactless and nondestructive way to monitor biological changes that are quantified by second-order statistics applied in the images in time using a secondary matrix known as time history of the speckle pattern (THSP). To avoid being time consuming, the traditional way to build the THSP restricts the data to a line or column. Our hypothesis is that the spatial restriction of the information could compromise the results, particularly when undesirable and unexpected optical inhomogeneities occur, such as in cell culture media. It tested a spatial random approach to collect the points to form a THSP. Cells in a culture medium and in drying paint, representing homogeneous samples in different levels, were tested, and a comparison with the traditional method was carried out. An alternative random selection based on a Gaussian distribution around a desired position was also presented. The results showed that the traditional protocol presented higher variation than the outcomes using the random method. The higher the inhomogeneity of the activity map, the higher the efficiency of the proposed method using random points. The Gaussian distribution proved to be useful when there was a well-defined area to monitor.