Pretreatment of lignocellulosic material with fungi capable of higher lignin degradation and lower carbohydrate degradation improves substrate acid hydrolysis and the eventual conversion to ethanol

Phanerochaete chrysosporium, Pycnoporus cinnabarinus,and fungal isolates RCK-1 and RCK-3 were tested for their lignin degradation abilities when grown on wheat straw (WS) and Prosopis juliflora (PJ) under solid-state cultivation conditions. Fungal isolate RCK-1 degraded more lignin in WS (12.26% and 22.64%) and PJ (19.30% and 21.97%) and less holocellulose in WS (6.27% and 9.39%) and PJ (3.01% and 4.58%) after 10 and 20 days, respectively, than other fungi tested. Phanerochaete chrysosporium caused higher substrate mass loss and degraded more of holocellulosic content (WS: 55.67%; PJ: 48.89%) than lignin (WS: 18.89%; PJ: 20.20%) after 20 days. The fungal pretreatment of WS and PJ with a high-lignin-degrading and low-holocellulose-degrading fungus (fungal isolate RCK-1) for 10 days resulted in (i) reduction in acid load for hydrolysis of structural polysaccharides (from 3.5% to 2.5% in WS and from 4.5% to 2.5% in PJ), (ii) an increase in the release of fermentable sugars (from 30.27 to 40.82 g L(-1) in WS and from 18.18 to 26.00 g L(-1) in PJ), and (iii) a reduction in fermentation inhibitors (total phenolics) in acid hydrolysate of WS (from 1.31 to 0.63 g L(-1)) and PJ (from 2.05 to 0.80 g L(-1)). Ethanol yield and volumetric productivity from RCK-1-treated WS (0.48 g g(-1) and 0.54 g L(-1) h(-1), respectively) and PJ (0.46 g g(-1) and 0.33 g L(-1) h(-1), respectively) were higher than untreated WS (0.36 g g(-1) and 0.30 g L(-1) h(-1), respectively) and untreated PJ (0.42 g g(-1) and 0.21 g L(-1) h(-1), respectively).     

White-rot fungal conversion of wheat straw to energy rich cattle feed

In order to improve the digestibility and nutrient availability in rumen, wheat straw was subjected to solid state fermentation (SSF) with white-rot fungi (i.e. Pleurotus ostreatus and Trametes versicolor) and the fermented biomass (called myco-straw) was evaluated for biochemical, enzymatic and nutritional parameters. The fungal treatment after 30 days led to significant decrease (P < 0.05) in cell wall constituents viz, acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, lignin and cellulose to the extent of 35.00, 38.88, 45.00, 37.48 and 37.86%, respectively in P. ostreatus fermented straw, while 30.04, 33.85, 39.90, 31.29 and 34.00%, respectively in T. versicolor fermented straw. However, maximum efficiency of fermentation in terms of low carbohydrate consumption per unit of lignin degradation, favoring cattle feed production was observed for P. ostreatus on the 10th day (17.12%) as compared with T. versicolor on the 30th day (16.91%). The myco-straw was found to contain significantly high (P < 0.05) crude protein (CP; 4.77% T. versicolor, 5.08% P. ostreatus) as compared to control straw (3.37%). Metabolizable energy (ME, MJ/kg DM), percent organic matter digestibility (OMD) and short chain fatty acids (SCFAs; mmol) production also increased considerably from control straw (4.40, 29.91 and 0.292) to a maximum up to P. ostreatus fermented straw (4.92, 33.39 and 0.376 on 20th day) and T. versicolor fermented straw (4.66, 31.74 and 0.334 on 10th day), respectively. Moreover, the myco-straw had lower organic carbon and was rich in nitrogen with lower C/N ratio as compared to control wheat straw. Results suggest that the fungal fermentation of wheat straw effectively improved CP content, OM digestibility, SCFAs production, ME value and simultaneously lowered the C/N ratio, thus showing potential for bioconversion of lignin rich wheat straw into high energy cattle feed.     

Hydrolytic potential of extracellular enzymes from a mutant strain of Fusarium oxysporum

Potential of extracellular enzymes of a mutant strain (NTG-19) of Fusarium oxysporum in hydrolysis of cellulosic materials was investigated. The enzyme preparation effectively hydrolyzed untreated as well as chemically pretreated sugarcane bagasse. About 95% hydrolysis could be achieved with sodium sulfite pretreated bagasse within 96 h. The enzymes exhibit appreciable stability during the course of hydrolysis.     

Enhanced production of cellulases byPenicillium citrinum in solid state fermentation of cellulosic residue

Penicillium citrinum, using rice husks in a solid state fermentation, produced maximum cellulase yields (37 Units/g) after 12 days with a cellulose utilization of more than 70%. Enzyme yields were three times higher than in shake-flask cultures.     

A hypercellulolytic mutant of Fusarium oxysporum

Multiple mutagenesis of Fusarium oxysporum DSM 841 resulted in enhanced yields of cellulases. The hypercellulolytic mutant (NTG-19) secretes high levels of extracellular cellulases on different cellulosic substrates. Addition of surfactant, Tween-80, further increased enzyme secretion by about 30%. The results on hydrolysis of wheat straw by parent strain, DSM 841 and mutant NTG-19 cellulases also revealed a significant improvement in the hydrolytic potential of the cellulolytic enzymes from the mutant NTG-19.     

Response of pigeon pea cultivars to water stress

Decrease in soil water potential during vegetative and flowering stages of two cultivars of pipeon pea (Cajanus cajari) caused higher decrease in relative water content in cv. ICPL-151 than in cv. H-77-216. Both cultivars showed partial recovery during rehydration. Cv. H-77-216 also accumulated more proline and carbohydrates during stress and showed better drought tolerance than cv. ICPL-151.     

Tetramethylpyrazine Attenuates Cognitive Impairment Via Suppressing Oxidative Stress,Neuroinflammation, and Apoptosis in Type 2 Diabetic Rats

Cognitive dysfunction is an important complication observed in type 2 diabetes mellitus (T2DM) patients. Tetramethylpyrazine (TMP) is known to exhibit anti-diabetic and neuroprotective properties. Therefore, the present study aimed to investigate the possible therapeutic effects of TMP against type 2 diabetes-associated cognitive impairment in rats. High-fat diet (HFD) followed by a low dose of streptozotocin (35 mg/kg) was used to induce diabetes in Sprague–Dawley rats. TMP (20, 40, and 80 mg/kg) and Pioglitazone (10 mg/kg) were administered for 4 weeks. The Morris water maze (MWM) and novel objective recognition task (NOR) tests were used to assess memory function. Fasting blood glucose (FBG), lipid profile, HOMA-IR, glycosylated hemoglobin (HbA1c), and glucose tolerance were measured. Acetylcholinesterase (AChE) and choline acetytransferase (ChAT) activity, acetylcholine (ACh) levels, oxidative stress, apoptotic (Bcl-2, Bax, caspase-3), and inflammatory markers (TNF-α, IL-1β, and NF-kβ) were assessed. BDNF, p-AKT, and p-CREB levels were also measured. In the present work, we observed that treatment of diabetic rats with TMP alleviated learning and memory deficits, improved insulin sensitivity, and attenuated hyperglycemia and dyslipidemia. Furthermore, treatment with TMP increased BDNF, p-Akt, and p-CREB levels, normalized cholinergic dysfunction, and suppressed oxidative, inflammatory, and apoptotic markers in the hippocampus. Collectively, our results suggest that the TMP may be an effective neuroprotective agent in alleviating type 2 diabetes-associated cognitive deficits.

     

Isolation of Three Xylanase-Producing Strains of Actinomycetes and Their Identification Using Molecular Methods

Eighty-eight actinomycetes were isolated from 20 samples collected from different locations in and around Delhi, India. Among these, 69 isolates were found positive for xylanase production. Of 69 isolates, 3 (SN32, SN77, and SN83) produced >125 IU/ml xylanase. Modern genetic tools were used for revealing the identities of these potent xylanase producers. The selected isolates were categorized under the genus Streptomyces based on their cultural and morphologic characteristics. Genetic diversity among these species of Streptomyces was established based on restriction length fragment polymorphism and random amplified polymorphic DNA analysis. The closest phylogenetic neighbours according to the 16S rRNA gene-sequence data for the three isolates SN32, SN77, and SN83 were Streptomyces cyaneus, S. tendae, and S. caelestis, respectively.