The production of fuels and other industrial products from renewable sources has intensified the search for new substrates or for the expansion of the use of substrates already in use, as well as the search for microorganisms with different metabolic capacities. In the present work, we isolated and tested a yeast from the soil of sugarcane irrigated with vinasse, that is, with high mineral content and acidic pH. The strain of Meyerozyma caribbica URM 8365 was able to ferment glucose, but the use of xylose occurred when some oxygenation was provided. However, some fermentation of xylose to ethanol in oxygen limitation also occurs if glucose was present. This strain was able to produce ethanol from molasses substrate with 76% efficiency, showing its tolerance to possible inhibitors. High ethanol production efficiencies were also observed in acidic hydrolysates of each bagasse, sorghum, and cactus pear biomass. Mixtures of these substrates were tested and the best composition was found for the use of excess plant biomass in supplementation of primary substrates. It was also possible to verify the production of xylitol from xylose when the acetic acid concentration is reduced. Finally, the proposed metabolic model allowed calculating how much of the xylose carbon can be directed to the production of ethanol and/or xylitol in the presence of glucose. With this, it is possible to design an industrial plant that combines the production of ethanol and/or xylitol using combinations of primary substrates with hydrolysates of their biomass.
Background and Purpose:
The literature has associated bone mineral density (BMD) and Alzheimer's disease (AD). The aim of the present systematic review was to investigate BMD in older adults with AD compared with older adults with no dementia.
Methods:
Searches were performed in the MEDLINE, EMBASE, CINAHL, and Web of Science databases from inception to May 2022. Observational studies that compared BMD in the populations of interest were included. Methodical quality (risk of bias) was appraised using the Newcastle-Ottawa Scale. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Standardized mean differences (SMD) were calculated for meta-analyses.
Results and Discussion:
Five studies were included, involving a total of 1772 older adults (373 with AD and 1399 with no dementia). A first meta-analysis compared 207 older adults with AD and 1243 with no dementia for BMD in the femoral neck. The results showed lower BMD in the AD groups (SMD =−1.52; 95% CI, −2.61 to −0.42; P = .007, low quality of evidence). A second meta-analysis considering different sites of the body (whole body, trunk, femur, and lumbar spine) also showed lower BMD in older adults with AD compared with the group with no dementia (SMD =−0.98; 95% CI, −1.91 to −0.05; P = .04, low quality of evidence). Newcastle-Ottawa Scale scores ranged from 7 to 9, indicating low risk of bias.
Conclusions:
Bone mineral density is lower in older adults with AD than in older adults with no dementia, especially in the femoral neck. These results suggest that older adults with AD may be at greater risk of developing osteopenia and osteoporosis. Current clinical practice guidelines should be amended for screening frequency and methodology for this particular cohort. Further studies are needed to confirm whether older people with AD have lower BMD in other sites of the body.
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