Smriti Shrivastava

Lignocelluloses are complex plant polysaccharides made of lignin, cellulose, and hemicellulose, and products made from these components find immense market potential. They can be effectively valorized to products related to bioenergy, bioplastics, food and nutrition, medication delivery systems, and other elements. Significant sources of lignocellulosic biomass include sugarcane bagasse, corn cob, rice straw, potato haulms, cocoa pods, etc. Enzyme-based valorization processes find immense potential, as they are eco-friendly and sustainable. A few prominent enzymes being used in the process, include hemicellulases (3.2.1.X), ligninases (EC 1.11.1.14), cellulases (EC 3.2.1.X), etc. These enzymes can be obtained from a diverse group of microorganisms and may be utilized in various industrial processes. The present review accounts for prominent lignocellulolytic enzymes, microbes producing these enzymes and their specific industrial applications. The review also highlights advances in enzyme production strategies and their production processes.

The conversion of plant‐based lignocellulosic materials into alternative fuels entails various pretreatment strategies (chemical, physico‐chemical or enzymatic) to boost the release of sugar constituents from biomass. This investigation reports the influence of different pretreatment techniques such as acid, alkali and steam treatment followed by enzymatic hydrolysis in single and (or) consolidated system, for releasing fermentable reducing sugars from sugarcane bagasse (SB) and corn cobs (CC) (major agricultural residues). Alkaline pretreatment facilitated maximal lignin removal, 83.2 and 69.4% from CC and SB, respectively, thereby expediting enzymatic hydrolysis by in‐house xylanases produced from indigenously isolated Aspergillus tubingensis strains, AUMS60 (Xyn60) and AUMS64 (Xyn64A, B). The major operating conditions for enzymatic treatment of raw and pretreated residues were set at a substrate loading of 2% (w/v), an enzyme loading of 100–500 U g⁻¹ substrate and incubation at 40°C, 140 rpm for 72 h. Treatment with Xyn60 and Xyn64A, B resulted in 81.4% (72 h) and 75.9% (24 h) saccharification of delignified SB and CC, respectively. Scanning electron micrographs and Fourier transform infrared spectra corroborated structural deformations induced by physico‐chemical pretreatment processes, thereby validating the maximal enzymatic hydrolysis of delignified substrates. The analysis of enzyme hydrolysis products suggested higher saccharification of hemicellulosic fraction as compared with cellulose. The observations of the present study signify that the thermotolerant in‐house enzymes show great potential in the saccharification of lignocelluloses within a short span of time and may open a new vista for biomass valorization in the bioenergy sector. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Patients affected by trauma who get admitted to critical care units experience prolonged hospitalization and thereby acquire several infections. This retrospective observational study was done from 2014 to 2021 to observe Candidaemia affecting this population. A total of 4816 patients admitted with traumatic injuries and hospitalized for treatment at ICU in our 190 bedded Level-1 Trauma center underwent this study. Paired blood samples were collected from patients showing signs of sepsis and incubated and monitored regularly by the BacT/ALERT system (bioMe´rieux InC., Marcy l'Etoile, France). All the positive signal samples exhibiting budding yeast cells on Gram stain were subcultured on Chrome agar and Sabouraud dextrose agar. Pure growths obtained were subjected for identification and susceptibility by MALDI-TOF and VITEK 2 system. Out of the 4816 patients, 61 were affected by Candidaemia. Out of 61, the maximum was in the age group of 31-40 years (19.7%). Male preponderance (50/61, 82%) was exhibited compared to females. To ascertain Candidaemia, samples collected were blood (63/66, 95.5%) and CVP tip (3/66, 4.5%). Candidaemia was primarily observed in patients who suffered major orthopedic trauma (14/61, 21.2%). A total of 66 Candida species were isolated from samples of these patients. Out of these, Candida tropicalis (43.9%) was the most common, followed by C. parapsilosis (22.7%), C. albicans (21.2%), C. haemulonii (4.5%), C. glabrata (3%), C. rugosa (3%), and C. guilliermondii (1.5%). Concerning antifungal resistance, fluconazole resistance was 16.6% (11), flucytosine 1.5% (1), amphotericin B 6% (4), and micafungin 3% (2). Voriconazole was resistant to none but intermediate to 12.1% (8), caspofungin was intermediate to 3% (2), and resistant to none. A total of 47% (31/61) of patients succumbed to their injuries which were observed highest in the age group of 61-70 years (8/61, 25.8%). The most common injuries that the deceased suffered were polytrauma (9/61, 29%) and blunt trauma abdomen (9/61, 29%). Maximum mortality was also observed in patients with Candidaemia due to Candida tropicalis (15/61, 48.3%). Candidaemia is usually fatal. Mortality due to Candidaemia increases in patients with severe traumatic injuries and added risk factors such as extremes of age, immunocompromised state, and broad-spectrum antibiotics. When compared to a similar study done in our center from 2009 to 2012 (3 years) on Candidaemia in ICU patients, the incidence was lower in our study (12.6% per 1000 ICU admissions vs 14.9% per 1000 ICU admissions), but the mortality rate was higher (47% vs 43.3%). Therefore, a watchful eye on early signs of sepsis, strict hospital infection control measures and antimicrobial stewardship may alter their outcome.

Xylitol is pentahydroxy sugar alcohol, existing in very trace amount in fruits and vegetables, and finds varied application in industries like food, pharma

The study aims to explore potential xylanase‐producing indigenous fungi isolated from soil and vegetable wastes containing plant degraded matter, reporting multilocus phylogenetic analysis and xylanase enzyme activity from selective strains. Four potential xylanolytic fungi were identified through distinct primary and secondary screening of 294 isolates obtained from the samples. Morphological characterization and multigene analysis (ITS rDNA, 18S rDNA, LSU rDNA, β‐tubulin, and actin gene) confirmed them as Aspergillus sp. AUMS56, Aspergillus tubingensis AUMS60 and AUMS64, and Aspergillus fumigatus AUKEMS24; achieving crude xylanase activities (through submerged fermentation using corn cobs) of 18.9, 32.29, 30.68, and 15.82 U ml⁻¹, respectively. AUMS60 and AUMS64 (forming lineage with A. tubingensis and Aspergillus niger in the same phylogroup with 100% Bayesian posterior probability support) secreted single xylanase (Xyn60; 36 kDa) and multiple xylanases (Xyn64A and Xyn64B; 33.4 and 19.8 kDa) respectively, having pH optima of 6.0 and exhibiting maximal activity at 60°C. These enzymes were highly stable at 40°C (120 h) and retained more than 70% activity at 50°C and at pH 5–6 (upon 72 h incubation). Our analysis suggested these enzymes to be endoxylanases demonstrating substrate hydrolysis within 15 min of reaction and maximum efficiency of xylanases from AUMS60 and AUMS64 achieving 51.1% (13 h) and 52.2% (24 h) saccharification, respectively. They also showed enhanced catalytic activity with various cations. Based on our investigation on xylan hydrolysis, we believe that these xylanases may find significant industrial applications as they have a real potential of working as a bio‐catalytic cocktail (patent file number: IN E1/38213/2020‐DEL) for the enhanced saccharification of lignocelluloses.

Lignocelluloses comprise of celluloses and hemicelluloses which can be effectively depolymerized to obtain fermentable sugars using diverse microbial enzymes, for subsequent conversion to various value-added products. Present study reports the bioprospecting of industrially significant microorganisms and their characterization to attain xylanases with high catalytic efficiency. Four potential xylanolytic fungi were identified through distinct primary and secondary screening process of 294 isolates from samples containing plant degrades. Morphological characterization and multigene analysis (ITS rDNA, 18S rDNA, nLSU rDNA, β-tubulin and actin gene) confirmed them Aspergillus niger AUMS56, Aspergillus tubingensis AUMS60, Aspergillus niger AUMS64 and Aspergillus fumigatus AUKEMS24 and their crude xylanase activities through submerged fermentation using corncob were 18.9, 32.29, 30.68 and 15.82 U ml^-1, respectively. AUMS60 and AUMS64 have highest catalytic activity of 1429 U g^-1 and 1243 U g^-1, respectively, all having pH and temperature optima of 6.0 and 60°C respectively, where AUMS60 produced single xylanase (Xyn60; 36 kDa) and AUMS64 secreted 2 probable isozymes (Xyn64A and Xyn64B; 33.4 and 19.8 kDa). Maximum saccharification efficiency of AUMS60 and AUMS64 were 51.1% (13 h) and 52.2% (24 h) showing enhanced catalytic activity with various cations. Present research reports potential xylanases from indigenous fungi, providing opportunity for development of bio-catalysts concoction (novelty established) for enhanced saccharification of complex lignocelluloses finding specific industrial applications for production of value-added components.