Protein engineering of GH11 xylanase from Aspergillus fumigatus RT-1 for catalytic efficiency improvement on kenaf biomass hydrolysis

Publication date: Available online 17 July 2019Source: Enzyme and Microbial TechnologyAuthor(s): Siti Intan Rosdianah Damis, Abdul Munir Abdul Murad, Farah Diba Abu Bakar, Siti Aishah Rashid, Nardiah Rizwana Jaafar, Rosli Md. IlliasAbstractEnzyme hydrolysis faces a bottleneck due to the recalcitrance of the lignocellulose biomass. The protein engineering of GH11 xylanase from Aspergillus fumigatus RT-1 was performed near the active site and at the N-terminal region to improve its catalytic efficiency towards pretreated kenaf (Hibiscus cannabinus) hydrolysis. Five mutants were constructed by combined approaches of error-prone PCR, site-saturation and site-directed mutagenesis. The double mutant c168 t/Q192H showed the most effective hydrolysis reaction with a 13.9-fold increase in catalytic efficiency, followed by mutants Y7L and c168 t/Q192 H/Y7L with a 1.6-fold increase, respectively. The enhanced catalytic efficiency evoked an increase in sugar yield of up to 28 % from pretreated kenaf. In addition, mutant c168 t/Q192 H/Y7L improved the thermostability at higher temperature and acid stability. This finding shows that mutations at distances less than 15 Å from the active site and at putative secondary binding sites affect xylanase catalytic efficiency towards insoluble substrates hydrolysis.
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research

Related Links:

Conclusion: We describe the first case of fungal necrotising scleritis without intraocular inflammation following pars plana vitrectomy (PubMed Search). Infection should be kept in the differential diagnosis of post-operative necrotising scleritis even in the absence of risk factors like hypopyon or diabetes. Early recognition improves final outcome. Medical therapy should be continued even after presumed cure to take care of residual fungi and prevent recurrences. PMID: 31429609 [PubMed - as supplied by publisher]
Source: Ocular Immunology and Inflammation - Category: Allergy & Immunology Tags: Ocul Immunol Inflamm Source Type: research
This study examined the feasibility oil palm empty fruit bunch (OPEFB) as the source of lignocellulose and Aspergillus niger as cellulase-producing fungus respectively. The hydrolysis was performed by growing A. niger on the OPEFB. Prior to hydrolysis, OPEFB was pretreated with NaOH at different percentage and were heated simultaneously at 170 °C to destroy lignin that hindered cellulase from contacting cellulose. A. niger was further grown on pretreated OPEFB and the reducing sugar was determined via dinitrosalicylic acid method with spectrophotometer reading at 540 nm periodically every 24 h for 9 consecutive d...
Source: Biocatalysis and Agricultural Biotechnology - Category: Biotechnology Source Type: research
In this study, samples of different kinds of silages (maize, grass, alfalfa, sugar beer pulp, immature corn and ryegrass) collected from farms located in four regions of Spain, were analysed to evaluate the occurrence of aflatoxins (AFs) and Fusarium mycotoxins. Their lactic acid bacteria and fungal populations as well as pH and water activity were also studied. Penicillium (4-26%), Geotrichum (2-21%) and Monascus (0.34-3%) were the main fungi identified in all the silages examined. Aspergillus was found in some maize, grass and alfalfa silage samples and Fusarium was only identified in 0.03% of grass silage samples. The i...
Source: Fungal Biology - Category: Biology Source Type: research
Case Report: A 63-year-old man had been diagnosed of chronic myelomonocytic leukemia on 2015 which was asymptomatic and not treated. On 2017, he presented abruptly with skin lesions that looked like bruises but were infiltrated and affected the face and upper back. Cutaneous and bone marrow biopsy ruled out leukemia cutis and it was diagnosed of blastic plasmacytoid dendritic cell neoplasm (BPDCN). Therefore he started chemotherapy using the protocol for acute lymphoblastic leukemia ALL OLD>55 years.
Source: Journal of the American Academy of Dermatology - Category: Dermatology Source Type: research
In conclusion, CreA, as a core regulatory gene in conidiation, provides new insight into the mechanism of conidiation in entomopathogenic fungi.
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
The clinical effects of Aspergillus fumigatus in the cystic fibrosis (CF) airway, with the exception of allergic bronchopulmonary aspergillosis, is unclear.
Source: Journal of Cystic Fibrosis - Category: Respiratory Medicine Authors: Source Type: research
Publication date: Available online 20 August 2019Source: LWTAuthor(s): R. Becerril, S. Manso, C. NerínAbstractThe influence of the growth of Aspergillus flavus and Escherichia coli on the concentration of the main compounds released by essential oils of cinnamon, clove and oregano has been studied. A diffusion vapour test and a subsequent analysis of three different areas of the plate were carried out. The results showed that in absence of microorganisms a gradient of concentration from the centre towards the periphery of the plate was observed for eugenol, carvacrol and cinnamaldehyde but not for thymol or linalool...
Source: LWT Food Science and Technology - Category: Food Science Source Type: research
Publication date: Available online 7 August 2019Source: Food ControlAuthor(s): Mohamed F. Abdallah, Kris Audenaert, Leonie Lust, Sofie Landschoot, Boris Bekaert, Geert Heasaert, Marthe De Boevre, Sarah De SaegerAbstractSugarcane juice is a traditional drink consumed on a daily basis in Egypt. The current work was conducted to (1) evaluate the multi-mycotoxin contamination in sugarcane juice, (2) identify the profiles of the mycotoxigenic fungi, and (3) assess the risk of mycotoxin exposure among the adult population. Sugarcane juice samples (n = 89) were randomly collected in two seasons from Egypt. Quantification of 1...
Source: Food Control - Category: Food Science Source Type: research
Publication date: Available online 19 August 2019Source: Biological ControlAuthor(s): Ashraf S. A. El-Sayed, Gul Shad AliAbstractPhytophthora spp are one of the most devastating pathogens to a wide range of crop plants. Chemical fungicides are commonly used for controlling Phytophthora diseases, however, due to environmental concerns and development of fungicide resistant Phytophthora strains, alternative low-risk method such as biological controls are the prospective approaches. In an in vitro bioactivity-driven screen of rhizosphere-inhabiting fungi, Aspergillus flavipes was identified as a strong inhibitor for growth of...
Source: Biological Control - Category: Biology Source Type: research
Publication date: Available online 16 August 2019Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): Chao Zhang, Siyao Liu, Shuangxi Li, Yue Tao, Panpan Wang, Xinyue Ma, Lanzhou ChenAbstractThe magnetic chitosan microspheres immobilized Aspergillus sydowii (MCMAs) was prepared and characterized by SEM, BET, XRD and VSM analyses, and used to adsorb Cu(II) from aqueous solution under different influence factors such as contact time, initial Cu(II) concentration and biosorbent dose. Characterization results showed that MCMAs had large specific surface area and were rapidly separated from aqueous...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research
More News: Aspergillus | Biotechnology | Hibiscus | Sugar