Optimization and comparison of the production of galactooligosaccharides using free or immobilized Aspergillus oryzae ß-galactosidase, followed by purification using silica gel.

The aim of this study was to optimize and compare the production of galactooligosaccharides (GOSs) by free and cotton cloth-immobilized Aspergillus oryzae ß-galactosidase, and perform economical evaluation of production of GOSs (100%) between them. Using the response surface method, the optimal reaction time (3.9 h), initial lactose concentration (57.13%), and enzyme to lactose ratio (44.81 U/g) were obtained for the free enzyme, which provided a GOSs yield of 32.62%. For the immobilized enzyme, the optimal yield of GOSs (32.48%) was obtained under reaction time (3.09 h), initial lactose concentration (52.74%), and temperature (50.0 ℃). And it showed desirable reusability during five successive enzymatic reactions. The recovery rate of GOSs (100%) is 65% using silica gel filtration chromatography. The economical evaluation showed almost no difference in the manufacturing cost for the GOSs (100%) between these two systems, and that the recovery rate had a great impact on the cost.

Production of butyric acid from acid hydrolysate of corn husk in fermentation by Clostridium tyrobutyricum: kinetics and process economic analysis.

BACKGROUND: Butyric acid is an important chemical currently produced from petrochemical feedstocks. Its production from renewable, low-cost biomass in fermentation has attracted large attention in recent years. In this study, the feasibility of corn husk, an abundant agricultural residue, for butyric acid production by using Clostridium tyrobutyricum immobilized in a fibrous bed bioreactor (FBB) was evaluated. RESULTS: Hydrolysis of corn husk (10% solid loading) with 0.4 M H2SO4 at 110 °C for 6 h resulted in a hydrolysate containing ~ 50 g/L total reducing sugars (glucose:xylose = 1.3:1.0). The hydrolysate was used for butyric acid fermentation by C. tyrobutyricum in a FBB, which gave 42.6 and 53.0% higher butyric acid production from glucose and xylose, respectively, compared to free-cell fermentations. Fermentation with glucose and xylose mixture (1:1) produced 50.37 ± 0.04 g L-1 butyric acid with a yield of 0.38 ± 0.02 g g-1 and productivity of 0.34 ± 0.03 g L-1 h-1. Batch fermentation with corn husk hydrolysate produced 21.80 g L-1 butyric acid with a yield of 0.39 g g-1, comparable to those from glucose. Repeated-batch fermentations consistently produced 20.75 ± 0.65 g L-1 butyric acid with an average yield of 0.39 ± 0.02 g g-1 in three consecutive batches. An extractive fermentation process can be used to produce, separate, and concentrate butyric acid to > 30% (w/v) sodium butyrate at an economically attractive cost for application as an animal feed supplement. CONCLUSION: A high concentration of total reducing sugars at ~ 50% (w/w) yield was obtained from corn husk after acid hydrolysis. Stable butyric acid production from corn husk hydrolysate was achieved in repeated-batch fermentation with C. tyrobutyricum immobilized in a FBB, demonstrating that corn husk can be used as an economical substrate for butyric acid production.

The impact of reimbursement systems on equity in access and quality of primary care: A systematic literature review.

BACKGROUND: Reimbursement systems provide incentives to health care providers and may drive physician behaviour. This review assesses the impact of reimbursement system on socioeconomic and racial inequalities in access, utilization and quality of primary care. METHODS: A systematic search was performed in Web of Science and PubMed for English language studies published between 1980 and 2013, supplemented by reference tracking. Articles were selected based on inclusion criteria, and data extraction and critical appraisal were performed by two authors independently. Data were synthesized in a narrative manner and categorized according to study outcome and reimbursement system. RESULTS: Twenty seven articles, mostly from the United States and United Kingdom, were included in the data synthesis. Reimbursement systems seem to have limited effect on socioeconomic and racial inequity in access, utilization and quality of primary care. Capitation might have a more beneficial impact on inequity in access to primary care and number of ambulatory care sensitive admissions than fee-for-service, but did worse in patient satisfaction. Pay-for-performance had little or no impact on socioeconomic and racial inequity in the management of diabetes, cardiovascular diseases, chronic obstructive pulmonary disease, and preventive services. CONCLUSION: We found little scientific evidence supporting an association between reimbursement system and socioeconomic or racial inequity in access, utilization and quality of primary care. Overall, few studies addressed this research question, and heterogeneity in context and outcomes complicates comparisons across studies. Further empirical studies are warranted.

Remarkable phylogenetic resolution of the most complex clade of Cyprinidae (Teleostei: Cypriniformes): a proof of concept of homology assessment and partitioning sequence data integrated with mixed model Bayesian analyses.

Despite many efforts to resolve evolutionary relationships among major clades of Cyprinidae, some nodes have been especially problematic and remain unresolved. In this study, we employ four nuclear gene fragments (3.3kb) to infer interrelationships of the Cyprinidae. A reconstruction of the phylogenetic relationships within the family using maximum parsimony, maximum likelihood, and Bayesian analyses is presented. Among the taxa within the monophyletic Cyprinidae, Rasborinae is the basal-most lineage; Cyprinine is sister to Leuciscine. The monophyly for the subfamilies Gobioninae, Leuciscinae and Acheilognathinae were resolved with high nodal support. Although our results do not completely resolve relationships within Cyprinidae, this study presents novel and significant findings having major implications for a highly diverse and enigmatic clade of East-Asian cyprinids. Within this monophyletic group five closely-related subgroups are identified. Tinca tinca, one of the most phylogenetically enigmatic genera in the family, is strongly supported as having evolutionary affinities with this East-Asian clade; an established yet remarkable association because of the natural variation in phenotypes and generalized ecological niches occupied by these taxa. Our results clearly argue that the choice of partitioning strategies has significant impacts on the phylogenetic reconstructions, especially when multiple genes are being considered. The most highly partitioned model (partitioned by codon positions within genes) extracts the strongest phylogenetic signals and performs better than any other partitioning schemes supported by the strongest 2Δln Bayes factor. Future studies should include higher levels of taxon sampling and partitioned, model-based analyses.

Integrating multi-origin expression data improves the resolution of deep phylogeny of ray-finned fish (Actinopterygii).

The actinopterygians comprise nearly one-half of all extant vertebrate species and are very important for human well-being. However, the phylogenetic relationships among certain groups within the actinopterygians are still uncertain, and debates about these relationships have continued for a long time. Along with the progress achieved in sequencing technologies, phylogenetic analyses based on multi-gene sequences, termed phylogenomic approaches, are becoming increasingly common and often result in well-resolved and highly supported phylogenetic hypotheses. Based on the transcriptome sequences generated in this study and the extensive expression data currently available from public databases, we obtained alignments of 274 orthologue groups for 26 scientifically and commercially important actinopterygians, representing 17 out of 44 orders within the class Actinopterygii. Using these alignments and probabilistic methods, we recovered relationships between basal actinopterygians and teleosts, among teleosts within protacanthopterygians and related lineages, and also within acanthomorphs. These relationships were recovered with high confidence.