The accumulation of agronomic wastes has caused several environmental problems, such as air and soil contamination, and insect and pathogen proliferation, among others. To mitigate this, studies have evaluated the use of these wastes as substrates for the cultivation of Pleurotus mushrooms, a low-cost/nutritionally important crop. This study aimed to evaluate the use of corn stubble and rice straw as substrates for the in vitro production of oyster mushrooms (Pleurotus ostreatus Jacq.) and the productive characterization (biological efficiency, production rate, earliness, daily productive capacity) of four isolated strains. The strains PO/A01, PO/A02, PO/A03, and PO/A04 were grown in Potato-Dextrose-Agar medium until complete colonization. The experiment was evaluated under a completely randomized design with 6 replications. Subsequently, the corn stubble and rice straw were disinfected, inoculated, bagged, incubated, and subjected to induction-fructification. The productive period ended after three harvests. At this stage, the experiment was conducted under a completely randomized design with a 4 × 2 factorial arrangement with 8 replications. The P. ostreatus strains inoculated in the corn stubble, compared to rice straw, showed 93.93% biological efficiency and a 2.07% production rate, representing increases of 30% and 50%, respectively. The strains PO/A03 and PO/A04 showed higher biological efficiency and organic matter loss. The PO/A02 strain showed greater earliness, with approximately 10 days to harvest. This study concluded that the isolated strains of P. ostreatus allow for the efficient use of corn stubble and rice straw, and can contribute to the management of agronomic wastes. Graphic abstract

The ability of edible mushrooms to modulate the intestinal microbiota is a topic of interest. This study shows that digested Pleurotus djamor powder (MUS) exhibits prebiotic effects during an in vitro colonic fermentation. Phenolic compounds, including epicatechin (3.03 ± 1.54 mg/L), gallic acid (2.71 ± 1.54 mg/L), and quercetin 3-glucoside (2.40 ± 1.54 mg/L), were found in P. djamor. MUS significantly increased the relative abundance of Lactobacillus spp./Enterococcus spp. (1.12% - 4.83%), Bifidobacterium spp. (0.59% - 1.85%), Ruminococcus albus/R. flavefaciens (0.37% - 1.88%), and reduced Clostridium histolyticum (2.89% - 1.22%) during 48 of colonic fermentation. MUS enhanced lactic acid and short-chain fatty acid production and decreased pH levels. The ¹H NMR analysis revealed the presence of essential amino acids, branched-chain amino acids, and other compounds that benefit human health. The results indicate the prebiotic effects of P. djamor on human intestinal microbiota.

Desertification is defined as land degradation in arid, semiarid, and dry sub-humid regions, and it is caused primarily by human activities and climate change. The semiarid region of Northeast (NE) Brazil is a very large, populous region, and thus, it is hard to monitor the dynamics of its desertified areas; therefore, the present study aimed to develop a minimum set of biophysical indicators to qualify and monitor desertification in this region. This approach included sampling a pair of preserved forested areas and nearby degraded, non-forested areas which had no vegetation growth in the previous years. The study was developed in four stages: (a) pilot site selection; (b) quantification and analysis of soil and vegetation biophysical indicators; (c) biophysical indicator selection; and (d) elaboration of the minimum set of biophysical indicators and desertification levels. Of the analyzed 24 biophysical indicators, 11 were retained and subjected to factor analysis by its principal components. This yielded the minimum set of indicators used to estimate the desertification levels of the pilot sites, which consisted of four soil characteristics: Total Organic Carbon (TOC), cation exchange capacity, clay content, and magnesium content. Regressions were conducted using the SQI, and these indicators showed that the TOC had the highest coefficient of determination. In an exploratory analysis, high SQI (low desertification) showed a positive correlation with the normalized difference vegetation index (R = 0.70) and Aridity Index (R = 0.97). This methodological approach could form the basis of a dynamic monitoring system that is capable of supplying objective, quantitative, and easy to obtain information to decision-makers in NE Brazil and other dry ecosystems around the globe.