RESUMEN
As an environmentally friendly and efficient method, successive two-step fermentation has been applied for extracting chitin from shrimp shells. To screen out the microorganisms for fermentation, a protease-producing strain, Exiguobacterium profundum, and a lactic acid-producing strain, Lactobacillus acidophilus, were isolated from the traditional fermented shrimp paste. Chitin was extracted by successive two-step fermentation with these two strains, and 85.9 ± 1.2% of protein and 95 ± 3% of minerals were removed. The recovery and yield of chitin were 47.82 and 16.32%, respectively. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) were used to characterize the chitin. The crystallinity index was 54.37%, and the degree of deacetylation was 3.67%, which was lower than that of chitin extracted by the chemical method. These results indicated that successive two-step fermentation using these two bacterial strains could be applied to extract chitin. This work provides a suitable strategy for developing an effective method to extract chitin by microbial fermentation.
RESUMEN
BACKGROUND: Parent-child play interactions offer an important avenue for supporting social development in children with autism spectrum disorder (ASD). Musical play is a natural and ubiquitous form of parent-child play. As a familiar, reinforcing, and predictable activity, musical play may support parent-child interactions by scaffolding children's attention to the play activities, while also providing parents with a familiar and accessible context to promote parental responsiveness. However, musical play may also impede interactions due to its sensory and repetitive components. METHOD: 12 parent-child dyads of preschoolers with ASD were video-recorded during a ten-minute play session that included musical and non-musical toys. Interactions were coded for parent and child musical engagement, as well as parental responsiveness. RESULTS: Parent-child dyads varied in their amount of musical engagement during play, which was not related to children's language level. Overall, parents showed similar levels of responsiveness to children's play across musical and non-musical activities, but type of parental responsiveness differed depending on the play context. Parents provided significantly more physical play responses and significantly fewer verbal responses during musical vs. non-musical engagement with their child. CONCLUSIONS: There are substantial individual differences in children with ASD's musical engagement during a parent-child free play. Children's musical engagement impacted type of parental responsiveness, which may relate to the familiarity, accessibility, and sensory nature of musical play/toys. Results suggest that musical play/toys can both support and hinder different types of parental responsiveness with implications for incorporation of musical activities into interventions.
RESUMEN
Chitin extraction from shrimp waste by protease-producing microorganisms was a positive and simple method. To improve the protease activity of microorganism used for the extraction of chitin, atmospheric and room temperature plasma technology was adopted to induce mutations in Exiguobacterium profundum, a protease-producing bacterium, which was isolated from traditional fermented shrimp paste. After several rounds of screening, the mutant numbered 10017 was screened. The hereditary properties of the mutant were found to be stable after a series of passages. This strain was subsequently used in the deproteinization process, which could remove 91.48% ± 2.60% protein, and the chitin recovery was 70.18 ± 2.68%. Fourier transform infrared spectrometry, X-ray diffraction, and scanning electron microscopy was adopted to compare the characteristics of the chitin extracted from mutagenized and wild-type strain fermentation. The crystallinity indices were 80.72% and 82.46%, and the degrees of deacetylation were 15.78% and 27.84%. These results indicated that the deproteinization by mutagenized strain fermentation might be applied to the production of chitin. Thus, the present study provides an appropriate strategy to develop an efficient method to improve protease activity in microbial fermentation.