Coffee is a socioeconomic important plant all over the world due to its exportation and how it provides income to the farmers and the country. However, potato taste defect (PTD) affects the Rwandan coffee quality. The smell is reported to be caused by some bacteria that are responsible for the off‐flavor and may also be related to the infestation of Antestia pest which are in its elimination process. The aim of this study was to isolate, biochemically characterize, and identify bacteria producing potato flavor from Rwandan coffee. Five samples were obtained from different regions (Nyamasheke and Nyakizu) of Rwanda. Bacteria were isolated and enumerated in the nutrient agar media followed by culture on nutrient and tryptic soy broth media. Bacteria were also cultured to several carbon sources such as glucose, fructose, sucrose, starch, pectin, and galactose to smell the odor produced by those bacteria. DNA extraction of isolates was done, and the resulting DNA strands were undergone three steps of PCR to be amplified using the forward primer and reverse primer. The identification of bacteria producing potato flavor from Rwandan coffee beans was done through 16S rDNA method followed by sequence analysis using FinchTV software and BLAST. Earthy odor was the mostly produced one for nutrient agar and tryptic soy agar media, and for carbon sources such as sucrose, glucose, pectin, fructose, and galactose. The potato odor was recorded mostly from damaged floaters and hand‐sorted damaged coffee beans. However, other odors such as fruity and ferment were found to be produced by bacteria in coffee beans. The study came up by concluding the presence of different kinds of bacteria including Enterobacteriaceae and Pantoea, which are responsible for the formation of 2‐isopropyl‐3‐methoxypyrazine (IMP) in coffee beans and cause the production of potato flavor.

Although groundwater serves as the predominant source of drinking water across many rural regions and certain urban areas of Rwanda, little is known about this resource. Anthropogenic impacts, such as faecal contamination, as well as geogenic water quality problems, including elevated arsenic, fluoride, iron, and manganese, are among the issues of concern for groundwater quality in Rwanda. Long-term groundwater monitoring can provide data on the evolution of groundwater quantity and quality. It helps to identify trends related to over-abstraction, reduced recharge, and pollution, which supporting resource management decisions. This review assesses the current state of groundwater monitoring in Rwanda by identifying the strengths and weaknesses of existing monitoring efforts, knowledge gaps, and opportunities for improved groundwater monitoring and management. The findings indicate that groundwater quality assessments are only conducted for specific purposes without considering broader issues and that groundwater monitoring in Rwanda is, in many respects, insufficient. Based on these findings, the following recommendations are made: (1) expand the existing groundwater monitoring network to encompass all groundwater types, geological settings, and anthropogenic pressures in Rwanda; (2) install rainfall gauging stations at or near the groundwater monitoring stations to enhance the interpretation of groundwater monitoring data; (3) conduct groundwater sampling campaigns at least twice a year, that include major ion analyses; and (4) to regularly analyze and disseminate the monitoring results.

Wastewater generated by academic institutions poses an environmental burden due to its composition, including household, food-related waste, and potential microcontaminants such as pharmaceutical and laboratory chemicals. This study evaluated wastewater from eleven academic institutions. Horizontal subsurface flow constructed wetlands (HSFCWs) filled with locally sourced volcanic gravel were tested for treatment performance at a selected site, the University of Rwanda, College of Science and Technology (UR-CST). Six HSFCWs operated continuously for four months: two planted with Cyperus latifolius, two with Juncus effusus, and two unplanted. Academic wastewater showed average concentrations of 715 mg/L COD, 54 mg/L NH₄⁺-N, 9 mg/L NO₃⁻-N, and 32 mg/L PO₄³⁻-P. A 4-day hydraulic retention time was effective for the treatment process. The HSFCWs achieved removal efficiencies of 69–82% (COD), 66–87% (NH₄⁺-N), 69–90% (NO₃⁻-N), and over 90% for TSS and PO₄³⁻-P, emphasizing the strong physical and chemical purification capacity of volcanic gravel as confirmed by XRF analysis. Juncus effusus outperformed Cyperus latifolius in biomass (6667 vs. 4389 g/m²) and nutrient assimilation per unit area, removing 3.75× more TP and 1.46× more TN. The desorption capacity of the substrate enabled potential phosphorus recovery of up to 50%. Volcanic gravel-based CWs offer an effective, low-cost, and sustainable approach to wastewater treatment with potential for nutrient recovery.

Lake Kivu, located between Rwanda and the Democratic Republic of the Congo, is subject to trace element contamination primarily due to the geological composition of its bedrock, watershed soils, and anthropogenic activities. In this study, we investigated the accumulation of trace elements in 13 fish species from Lake Kivu, with samples obtained from fishermen in Rubavu, Karongi, and Rusizi. The fish samples were digested and analyzed for selected trace element concentrations using atomic absorption spectrophotometry (AAS). The concentrations of trace elements in the fish ranged from 0.07 to 2.53 mg/kg for mercury (Hg), 0.69 to 1.16 mg/kg for cadmium (Cd), 0.28 to 0.76 mg/kg for copper (Cu), 2.58 to 3.83 mg/kg for chromium (Cr), and 0.22 to 0.68 mg/kg for manganese (Mn). The highest bio‐concentration factor (BCF) was observed for mercury. Oreochromis niloticus exhibited significantly higher BCFs for mercury compared to other species, with a value of 16,867 L/kg. Haplochromis scheffersi also displayed a high BCF for mercury at 3533 L/kg, followed by Labeo victorianus with a BCF of 2867 L/kg. Mercury (Hg) posed a potential risk for adults in 77% of the fish species analyzed, as indicated by target hazard quotient (THQ) values exceeding 1. Additionally, Cd, Cr, and Hg posed potential risks for children in over 75% of the fish species analyzed. Continuous monitoring of trace element sources and concentrations in the water column and fish of Lake Kivu is urgently needed to assess contamination sources and exposure levels.

The jigsaw cooperative learning method involves dividing a topic into segments, with each student mastering one part in an expert group and teaching it to their home group. This method fosters collaboration, critical thinking, and mutual accountability, as each student's contribution is essential for the group's overall understanding of the learning concept. Thus, this study explored the effectiveness of the jigsaw method in teaching biotechnology to undergraduates’ university students. A mixed-method research design was employed, utilizing both quantitative and qualitative approaches. The intervention involved 40 students, with data collected through tests, Likert scale questionnaires and interview. Quantitative data were analyzed using descriptive and inferential statistics, while qualitative data were thematically analyzed. The findings revealed that students taught using the jigsaw method scored significantly higher than those who received traditional lectures and expressed positive perceptions about the outcomes of the method. The benefits highlighted by students included enhanced communication skills, teamwork, knowledge retention, a fun learning atmosphere, and increased self-esteem. However, challenges such as time constraints and limited guidance were also noted. The study concluded that the jigsaw method significantly improved teaching and learning outcomes in biotechnology. Further research is recommended to explore the impact of this approach on other subjects at different levels of learning.