Rice straw hydrolysis using in-situ produced enzymes: Feedstock influences fungal enzyme composition and hydrolytic efficiency

Trichoderma reesei RUT-C30 was cultivated on differentially pretreated rice straw and pure cellulose as a carbon source/inducer for cellulase production, and the enzymes were evaluated for hydrolysis of sequential acid and alkali pretreated rice straw. Growth on pretreated rice straw enhanced protein secretion and cellulase activities compared to pure cellulose as a carbon source. The yield of cellulolytic enzymes was higher for alkali pretreated rice straw (ALP-RS), while H2O2-treated (HP-RS) could not induce cellulases to a larger level compared to pure cellulose. Protein concentration was 3.5-fold higher on ALP-RS as compared to pure cellulose, with a maximum filter-paper cellulase (FPase) activity of 1.76 IU/ml and carboxy-methyl cellulase (CMCase) activity of 40.16 IU/ml (2.18 fold higher). Beta-glucosidase (BGL) activity was more or less the same with the different substrates and supplementation of heterologous BGL could result in a quantum jump in hydrolytic efficiencies, which in the case of ALP-RS induced enzymes was 34% (increased from 69.26% to 92.51%). The use of lignocellulosic biomass (LCB) itself as a substrate for the production of cellulase is advantageous not only in terms of raw material costs but also for obtaining a more suitable enzyme profile for biomass hydrolysis.

Recent advances in biodiesel production: Challenges and solutions

Mono alkyl fatty acid ester or methyl ethyl esters (biodiesel) are the promising alternative for fossil fuel or petroleum derived diesel with similar properties and could reduce the carbon foot print and the greenhouse gas emissions. Biodiesel can be produced from renewable and sustainable feedstocks like plant derived oils, and it is biodegradable and non-toxic to the ecosystem. The process for the biodiesel production is either through traditional chemical catalysts (Acid or Alkali Transesterification) or enzyme mediated transesterification, but as enzymes are natural catalysts with environmentally friendly working conditions, the process with enzymes are proposed to overcome the drawbacks of chemical synthesis. At present 95% of the biodiesel production is contributed by edible oils worldwide whereas recycled oils and animal fats contribute 10% and 6% respectively. Although every process has its own limitations, the enzyme efficiency, resistance to alcohols, and recovery rate are the crucial factors to be addressed. Without any benefit of doubt, production of biodiesel using renewable feedstocks and enzymes as the catalysts could be recommended for the commercial purpose, but further research on improving the efficiency could be an advantage.

Enzymatic approaches in the bioprocessing of shellfish wastes

Several tonnes of shellfish wastes are generated globally due to the mass consumption of shellfish meat from crustaceans like prawn, shrimp, lobster, crab, Antarctic krill, etc. These shellfish wastes are a reservoir of valuable by-products like chitin, protein, calcium carbonate, and pigments. In the present scenario, these wastes are treated chemically to recover chitin by the chitin and chitosan industries, using hazardous chemicals like HCl and NaOH. Although this process is efficient in removing proteins and minerals, the unscientific dumping of harmful effluents is hazardous to the ecosystem. Stringent environmental laws and regulations on waste disposal have encouraged researchers to look for alternate strategies to produce near-zero wastes on shellfish degradation. The role of enzymes in degrading shellfish wastes is advantageous yet has not been explored much, although it produces bioactive rich protein hydrolysates with good quality chitin. The main objective of the review is to discuss the potential of various enzymes involved in shellfish degradation and their opportunities and challenges over chemical processes in chitin recovery.

Sustainable and eco-friendly strategies for shrimp shell valorization

Among the seafood used globally, shellfish consumption is in great demand. The utilization of these shellfish such as prawn/shrimp has opened a new market for the utilization of the shellfish wastes. Considering the trends on the production of wealth from wastes, shrimp shell wastes seem an important resource for the generation of high value products when processed on the principles of a biorefinery. In recent years, various chemical strategies have been tried to valorize the shrimp shell wastes, which required harsh chemicals such as HCl and NaOH for demineralization (DM) and deproteination (DP) of the shrimp wastes. Disposal of chemicals by the chitin and chitosan industries into the aquatic bodies pose harm to the aquatic flora and fauna. Thus, there has been intensive efforts to develop safe and sustainable technologies for the management of shrimp shell wastes. This review provides an insight about environmentally-friendly methods along with biological methods to valorize the shrimp waste compared to the strategies employing concentrated chemicals. The main objective of this review article is to explain the utilization shrimp shell wastes in a productive manner such that it would be offer environment and economic sustainability. The application of valorized by-products developed from the shrimp shell wastes and physical methods to improve the pretreatment process of shellfish wastes for valorization are also highlighted in this paper.

0303 Heart Rate and Systolic Blood Pressure Increase During Experimental Sleep Restriction

Introduction

Experimental sleep restriction is associated with elevated daytime cardiac activity, including heart rate (HR) and blood pressure (BP). However, some studies have found changes in systolic (SBP) but not diastolic blood pressure (DBP) or found changes in neither. Although findings are mixed, there may be a dose-response effect of cumulative sleep loss on daytime cardiac activity, such that HR and BP increase above basal levels with additional nights of insufficient sleep. This study examined changes in cardiac activity during experimental sleep restriction.

Methods

We used multilevel models with random effects for individuals to analyze data from 15 healthy males (M=22.3 years old, SD=2.8) in an 11-day inpatient protocol consisting of three nights of 10-hour/night baseline sleep opportunity, five nights of sleep restriction (5-hour/night sleep opportunity), and then two recovery nights (10-hour/night sleep opportunity). HR and BP were measured approximately every two hours during wake.

Results

HR increased 0.75 beats/minute with each successive night of sleep restriction (SE=0.18, p<0.001). HR was 5.13 beats/minute higher during the recovery condition than during baseline or sleep restriction (SE=1.05, p<0.001). During sleep restriction only, HR was lower in the later morning and evening compared to the earliest morning timepoint of the day, F(10, 743)=10.44, p<0.001. SBP increased 0.33 mmHg following each successive night of sleep restriction (SE=0.16, p=0.041); however, SBP was only marginally higher during the sleep restriction condition than during baseline (b=1.90, SE=1.09, p=0.082).

Conclusion

Our findings suggest that HR and SBP increase with each additional day of experimental sleep restriction, even after accounting for diurnal effects on HR and SBP. HR did not recover to baseline levels following a night of recovery sleep, suggesting that longer recovery sleep may be necessary to recover from a week of sleep restriction.

Support

Grant UL1TR000127 (Chang PI), Clinical and Translational Science Institute; College of Health and Human Development at Pennsylvania State University.

0296 Less Self-Reported Alertness and Motivation During Sleep Restriction are Associated with Decreased Attentional Performance

Introduction

Some individuals demonstrate more performance decrements on the psychomotor vigilance task (PVT) after sleep restriction (SR). We investigated whether individuals who reported less alertness and/or less motivation after SR demonstrated poorer performance on the PVT.

Methods

Fifteen healthy men (22.3±2.8 years) participated in a 10-night inpatient protocol with three nights of 10-hour baseline time in bed (TIB), five nights of SR (5-hour TIB), then two recovery (10-hour TIB) nights. Participants completed the 10-minute PVT (Joggle Research® battery) approximately every two hours during wake. Outcomes included number of false starts (<100 ms reaction time, RT) and number of lapses (≥500 ms RT). Participants reported alertness and motivation levels after each PVT. Median splits were used to characterize changes in alertness (“sleepy,” n=8, versus “alert,” n=7) and motivation (“unmotivated,” n=7, versus “motivated,” n=8) from the last day of baseline to the last day of SR. Outcomes were analyzed in mixed models with the predictor day*alertness or day*motivation, excluding the first three baseline days to preclude practice effects.

Results

There were significant interactions between day and alertness (p=.025) and day and motivation (p=.043) for false starts. False starts followed a quadratic inverted-U shape across days in sleepy (b=-0.16, p=.003) and unmotivated (b=-0.16, p=.004) participants, but not in alert or motivated participants (p>.05). There was a significant interaction between day and alertness for lapses (p=.008); lapses followed a quadratic inverted-U shape across days with a stronger effect in sleepy (b=-0.43, p<.001) versus alert (b=-0.15, p=.031) participants. There was no interaction between day and motivation for lapses.

Conclusion

Participants reporting less alertness were more likely to make both false starts and lapses after SR; those reporting less motivation were more likely to make false starts, but not lapses. Findings suggest greater motivation is sufficient to preserve inhibitory control but not vigilance after sleep restriction. In contrast, greater alertness despite sleep restriction was sufficient to preserve inhibitory control and resulted in lower vigilance decrements.

Support

This study was funded by grant UL1TR000127 from the Clinical and Translational Science Institute and the College of Health and Human Development at the Pennsylvania State University (Chang PI).

0085 Vulnerability to Sleep Restriction is Associated with Decreased Working Memory Performance

Introduction

We investigated whether individuals with more lapses on the psychomotor vigilance task (PVT) after sleep restriction (SR) demonstrated poorer working memory compared to those with fewer PVT lapses.

Methods

Fifteen healthy men (22.3±2.8 years) participated in a 10-night inpatient protocol with three nights of 10-hour baseline time in bed (TIB), five nights of SR (5-hour TIB), then two recovery (10-hour TIB) nights. Participants completed the Visual Object Learning Task (VOLT) and Fractal 2-Back (F2B; visual n-back) measuring working memory and the PVT (Joggle Research® battery) approximately every two hours during wake. During the VOLT, participants indicated whether presented images had been shown previously. Outcomes included number of misses and false alarms. During the F2B, participants tapped the screen when an image appeared that had been shown 2 images previously. Outcomes included sensitivity and specificity. Median split of mean PVT lapses after the last night of SR was used to categorize participants into “vulnerable” (n=8) versus “resistant” (n=7) groups. Outcomes were analyzed in mixed models with the predictor day*vulnerability, excluding the first three baseline days to preclude practice effects.

Results

There was a significant interaction between day and attentional vulnerability for VOLT misses (p<.001); misses increased linearly across days in vulnerable (b=.18, p<.001) but not resistant (p=.956) participants. There was no interaction between day and vulnerability for VOLT false alarms, which did not change across days. There was a significant interaction between day and attentional vulnerability for F2B sensitivity (p=.002); sensitivity increased linearly across days in resistant (b=.02, p<.001) but not in vulnerable (p=.273) participants. There was no interaction between day and vulnerability for F2B specificity, which did not change across days.

Conclusion

Performance on the VOLT decreased in vulnerable participants only; performance on the F2B improved in resistant participants likely due to practice effects not seen in vulnerable participants. Findings indicate vulnerability to attentional lapses after SR is a marker of vulnerability to working memory decrements.

Support

This study was funded by grant UL1TR000127 from the Clinical and Translational Science Institute (Chang PI) and the College of Health and Human Development at the Pennsylvania State University.

Biogenic Ag Nanoparticles from Neem Extract: Their Structural Evaluation and Antimicrobial Effects against Pseudomonas nitroreducens and Aspergillus unguis (NII 08123)

Silver nanocrystals have been successfully fabricated by the bioreduction route using the ethanolic extract of Azadirachta indica (neem) leaves as the reducing and capping agent without solvent interference. The silver nanocrystals were grown in a single-step method, without the influence of external energy or surfactants, and at room temperature. The nanoparticles were prepared from different ratios of silver ions to reducing agent molecules and were characterized by UV-vis spectroscopy and transmission electron microscopy (TEM). The nanoparticles were roughly spherical and polydispersed with diameters of less than 40 nm, as determined with high-resolution transmission electron microscopy (HRTEM). Fast Fourier transform (FFT) analysis and X-ray diffraction (XRD) analysis elucidated the crystalline nature of the nanoparticles. The presence of participating functional groups was determined with Fourier transform infrared (FTIR) spectroscopy. The synthesized silver nanoparticles were analyzed as a potential surface-enhanced Raman spectroscopy (SERS) substrate by incorporating rhodamine B as the Raman reporter molecule. The bioreduction process was monitored through SERS fingerprint, which was evaluated by the change in vibrational energies of metal-ligand bonds. It was possible to detect the SERS spectral pattern of the probe molecules on the Ag nanoparticles without the use of any aggregating agent. Thus, the formation of probable intra- and interparticle hot spots was attributed to evaporation-induced aggregation. Furthermore, stirring and precursor salt concentration influenced the kinetics involved in the fabrication process. The thermal stability of the lyophilized nanoparticles prepared from 0.1 M AgNO₃ was evaluated with thermogravimetric analysis (TGA) and had a residual mass of 60% at 600 °C. X-ray photoelectron spectroscopy (XPS) studies were used to validate the compositional and chemical-state information. The biomass-capped silver nanoparticles provided antimicrobial activity by inhibiting the growth of Pseudomonas nitroreducens, a biofilm-forming bacterium, and the fungus, Aspergillus unguis (NII 08123).

Genomic sequence analysis of a plant-associated Photobacterium halotolerans MELD1: from marine to terrestrial environment?

Mercury impacts the function and development of the central nervous system in both humans and wildlife by being a potent neurotoxin. Microbial bioremediation is an important means of remediation of mercury-contaminated soil. The rhizospheric Photobacterium halotolerans strain MELD1 was isolated from mercury and dioxin contaminated site from Tainan, Taiwan. It has been shown to reduce Hg²⁺ to Hg⁰. The 4,758,027 bp genome of P. halotolerans MELD1 has a G + C content of 50.88 % and contains 4198 protein-coding and 106 RNA genes. Genomic analysis revealed the presence of a number of interesting gene cluster that maybe involved in heavy metal resistance, rhizosphere competence and colonization of the host plant.

A rhizosphere-associated symbiont, Photobacterium spp. strain MELD1, and its targeted synergistic activity for phytoprotection against mercury

Though heavy metal such as mercury is toxic to plants and microorganisms, the synergistic activity between them may offer benefit for surviving. In this study, a mercury-reducing bacterium, Photobacterium spp. strain MELD1, with an MIC of 33 mg x kg(-1) mercury was isolated from a severely mercury and dioxin contaminated rhizosphere soil of reed (Phragmites australis). While the whole genome sequencing of MELD1 confirmed the presence of a mer operon, the mercury reductase MerA gene showed 99% sequence identity to Vibrio shilloni AK1 and implicates its route resulted from the event of horizontal gene transfer. The efficiency of MELD1 to vaporize mercury (25 mg x kg(-1), 24 h) and its tolerance to toxic metals and xenobiotics such as lead, cadmium, pentachlorophenol, pentachloroethylene, 3-chlorobenzoic acid, 2,3,7,8-tetrachlorodibenzo-p-dioxin and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin is promising. Combination of a long yard bean (Vigna unguiculata ssp. Sesquipedalis) and strain MELD1 proved beneficial in the phytoprotection of mercury in vivo. The effect of mercury (Hg) on growth, distribution and tolerance was examined in root, shoot, leaves and pod of yard long bean with and without the inoculation of strain MELD1. The model plant inoculated with MELD1 had significant increases in biomass, root length, seed number, and increased mercury uptake limited to roots. Biolog plate assay were used to assess the sole-carbon source utilization pattern of the isolate and Indole-3-acetic acid (IAA) productivity was analyzed to examine if the strain could contribute to plant growth. The results of this study suggest that, as a rhizosphere-associated symbiont, the synergistic activity between the plant and MELD1 can improve the efficiency for phytoprotection, phytostabilization and phytoremediation of mercury.

Synergistic collaboration of gut symbionts in Odontotermes formosanus for lignocellulosic degradation and bio-hydrogen production

In this work, gut microbes from the macrotermitine termite Odontotermes formosanus the cellulolytic Bacillus and fermentative Clostridium were studied in batch experiments using different carbon substrates to bio-mimic the termite gut for hydrogen production. Their fungus comb aging and the in vitro lignocellulosic degradation of the mango tree substrates by the synergistic interaction of Bacillus, Clostridium and Termitomyces were detected by Solid-state NMR. From the results, Bacillus species acted as a mutualist, by initiating an anaerobic environment for the growth of Clostridium, for bio-hydrogen production and the presence of Termitomyces enhanced the lignocellulosic degradation of substrates in vitro and in vivo. Thus, the synergistic collaboration of these three microbes can be used for termite-derived bio-fuel processing technology.