Hydrolytic Enzyme Activities Research Articles

Reconsidering hydrolysis kinetics for anaerobic digestion of waste activated sludge applying cascade reactors with ultra-short residence times

Hydrolysis is considered to be the rate-limiting step in anaerobic digestion of waste activated sludge (WAS). In this study, an innovative 4 stages cascade anaerobic digestion system was researched to (1) comprehensively clarify whether cascading configuration enhances WAS hydrolysis, and to (2) better understand the governing hydrolysis kinetics in this system. The cascade system consisted of three 2.2 L ultra-short solids retention times (SRT) continuous stirred tank reactors (CSTRs) and one 15.4 L CSTR. The cascade system was compared with a reference conventional CSTR digester (22 L) in terms of process performance, hydrolytic enzyme activities and microbial community dynamics under mesophilic conditions (35 °C). The results showed that the cascade system achieved a high and stable total chemical oxygen demand (tCOD) reduction efficiency of 40–42%, even at 12 days total SRT that corresponded to only 1.2 days SRT each in the first three reactors of the cascade. The reference-CSTR converted only 31% tCOD into biogas and suffered process deterioration at the applied low SRTs. Calculated specific hydrolysis rates in the first reactors of the cascade system were significantly higher compared to the reference-CSTR, especially at the lowest applied SRTs. The activities of several hydrolytic enzymes produced in the different stages revealed that protease, cellulase, amino peptidases, and most of the tested glycosyl-hydrolases had significantly higher activities in the first three small digesters of the cascade system, compared to the reference-CSTR. This increase in hydrolytic enzyme production by far exceeded the increase in specific hydrolysis rate, indicating that hydrolysis was limited by solids-surface availability for enzymatic attack. Correspondingly, high relative abundances of hydrolytic-fermentative bacteria and hydrogenotrophic methanogens as well as the presence of syntrophic bacteria were found in the first three digesters of the cascade system. However, in the fourth reactor, acetoclastic methanogens dominated, similarly as in the reference-CSTR. Overall, the results concluded that using multiple CSTRs that are operated at low SRTs in a cascade mode of operation significantly improved the enzymatic hydrolysis rate and extend in anaerobic WAS digestion. Moreover, the governing hydrolysis kinetics in the cascading reactors were far more complex than the generally assumed simplified first-order kinetics.

Differential Organic Carbon Mineralization Responses to Soil Moisture in Three Different Soil Orders Under Mixed Forested System

Soil microbial respiration is one of the largest sources of carbon (C) emissions to the atmosphere in terrestrial ecosystems, which is strongly dependent on multiple environmental variables including soil moisture. Soil moisture content is strongly dependent on soil texture, and the combined effects of texture and moisture on microbial respiration are complex and less explored. Therefore, this study examines the effects of soil moisture on the mineralization of soil organic C Soil organic carbon in three different soils, Ultisol, Alfisol and Vertisol, collected from mixed forests of Georgia, Missouri, and Texas, United States , respectively. A laboratory microcosm experiment was conducted for 90 days under different moisture regimes. Soil respiration was measured weekly, and destructive harvests were conducted at 1, 15, 60, and 90 days after incubation to determine extractable organic C (EOC), phospholipid fatty acid based microbial community, and C-acquiring hydrolytic extracellular enzyme activities (EEA). The highest cumulative respiration in Ultisol was observed at 50% water holding capacity (WHC), in Alfisol at 100% water holding capacity, and in Vertisol at 175% WHC. The trends in Extractable Organic Carbon were opposite to that of cumulative microbial respiration as the moisture levels showing the highest respiration showed the lowest EOC concentration in all soil types. Also, extracellular enzyme activities increased with increase in soil moisture in all soils, however, respiration and EEA showed a decoupled relationship in Ultisol and Alfisol soils. Soil moisture differences did not influence microbial community composition.

The enzyme activity dynamic relationship with the content of structural polypeptides of enterocyte membranes in cattle fetal

The article performs new data on the relationship between the hydrolytic and transport enzyme activity at different poles of the enterocytes plasmolemma of cow's fetal large intestine with the content of individual fractions of polypeptides. An expressive direct dependence of enzyme activity dynamics on the apical and basolateral membranes of enterocytes containing low molecular weight proteins and an inverse relationship with the concentration of proteins with medium and large molecular weights has been proved. It was found that the alkaline activity of the phosphatase and γ-glutamyltransferase on the apical domain of enterocyte plasmolemma is directly related to the proteins content with molecular masses of 9.6–14.2 kD, 21 kD, 22.5 kD, 26 kD, 33 kD, 35 kD, 170–185 kD, and 205 kD (P ≤ 0.05–0.001). Gamma-glutamyltransferase activity is straightly related to protein quantity with molecular weights of 15.5 kDa and 39 kD (P ≤ 0.05). In contrast, alkaline phosphatase and GGT activity have inverse correlations with the content of polypeptides with molecular masses of 46 kD, 63 kD, and 250 kD in the apical membrane of enterocytes (P ≤ 0.01–0.001). The lactase activity in the cattle enterocytes apical membrane during the test period has significant direct correlations only with the amount of the polypeptide of polypeptides with molecular weights of 31 kD, 39 kD, and 100 kD (P ≤ 0.05–0.01) and inverse relationships containing proteins with molecular masses of 46 kD and 120 kD (P ≤ 0.05). A linear dependence of the different ATPase activity of the apical membrane of red blood cells containing proteins with molecular weights of 9.6–14.2 kD, 15.5 kD, 21 kD, 22.5 kD, 33 kD, 35 kD, 39 kD, and 205 kD (P ≤ 0.05–0.001) was observed. Alkaline phosphatase activity in the apical membrane of enterocytes is only directly related to the number of proteins with molecular weights of 17 kD and 24 kD (P ≤ 0.001) in this domain. It inversely depends on the content of proteins with molecular masses of 9.6–14.2 kD and 52 kD (P ≤ 0.001). G-glutamyltransferase activity is inversely related to protein content with molecular weights of 43 kD, 52 kD, 66 kD, 87 kD, and 100 kD and 155 kD (P ≤ 0.001). The Ca2+, Mg2+-ATPase of the basolateral membrane activity of enterocytes is directly related to the protein amount with molecular weights of 26 kD (P ≤ 0.01), Mg2+-ATPase and Mg2+-ATPase with protein content with the molecular value of 100 kD (P ≤ 0.05).

Performance and microbial community analysis of anaerobic sludge digestion enhanced by in-situ microaeration

The effectiveness of in-situ microaeration was investigated with varied air dosages [0–25 mL/(L·d)] to enhance mesophilic anaerobic digestion (AD) of sludge in semi-continuous systems in terms of specific biogas production and volatile solids (VS) removal rate, focusing on performance evaluation, microbial community analysis, and underlying mechanisms. The optimal dosage of 12.5 mL/(L·d) increased specific biogas production by 15.8 ± 7.3% and enhanced VS removal by 18.3 ± 1.6%. In-situ microaeration stimulated activity of hydrolytic enzymes, enlarged sludge particle size, and improved sludge dewaterability. MiSeq sequencing analysis showed that dominant bacterial and archaeal communities were remarkably different between in-situ microaeration and obligate AD process. The presence of oxygen enriched relative abundances of Deltaproteobacteria, Anaerolineae, Clostridia, Synergistia and Caldilineae, enabling the acid-producing process to metabolize more types of substrates. Due to the selective enrichment, in-situ microaeration significantly enriched aceticlastic methanogens rather than hydrogenotrophic methanogens in the AD reactor. Analysis of coupling microaeration pretreatment and in-situ microaeration for anaerobic digestion indicated that excessive microaeration decreased VS removal rate and methane yield owing to substrates consumption by facultative bacteria. In-situ microaeration-based AD could be a promising process for sludge treatment and bioenergy recovery.

(Invited) Tailored Functionalization of Single-Walled Carbon Nanotubes for Real-Time Monitoring of Hydrolytic Enzymes Activity

Single-walled carbon nanotubes (SWCNTs) have unique optical and physical properties, and they benefit from the ease of surface functionalization and biocompatibility. Semiconducting SWCNTs fluoresce in the near-infrared (nIR) part of the spectrum, which overlaps with the transparency window of biological samples. The SWCNTs fluorescence is sensitive to the environment, and depending on the surface functionalization, subtle changes in the proximity of the nanotube can result in significant spectral modulations. Hence, SWCNTs can be utilized as optical sensors enabling real-time detection with optical signal transduction1–3. Here, we demonstrate tailored functionalization of SWCNTs, which render the nanotubes substrate for hydrolytic enzymes. We show that the chemical composition and functional groups of the SWCNTs wrapping mediate the interaction between the nanotube and the enzymes. Our results open new avenues for monitoring enzymatic activity with fluorescent nanoparticles and hold great promise for biomedical research and applications.Reference(1) Hendler-Neumark, A.; Bisker, G. Fluorescent Single-Walled Carbon Nanotubes for Protein Detection. Sensors 2019, 19 (24), 5403.(2) Bisker, G.; Bakh, N. A.; Lee, M. A.; Ahn, J.; Park, M.; O’Connell, E. B.; Iverson, N. M.; Strano, M. S. Insulin Detection Using a Corona Phase Molecular Recognition Site on Single-Walled Carbon Nanotubes. ACS Sensors 2018, 8 (2), 367–377.(3) Bisker, G.; Dong, J.; Park, H. D.; Iverson, N. M.; Ahn, J.; Nelson, J. T.; Landry, M. P.; Kruss, S.; Strano, M. S. Protein-Targeted Corona Phase Molecular Recognition. Nat. Commun. 2016, 7, 1–14.

Yeasts isolated from a lotic continental environment in Brazil show potential to produce amylase, cellulase and protease

Yeasts have wide applicability in the industrial field, as in the production of enzymes used in biocatalysts. Biocatalysts are more efficient when compared to chemical catalysts, with emphasis on hydrolytic enzymes, such as amylase, cellulase and protease. Here we focused on prospecting yeasts, with a high capacity to synthesize hydrolytic enzymes, from a continental lotic ecosystem environment in Brazil. 75 yeasts were grown in Yeast Extract-Peptone-Dextrose (YPD) medium supplemented with antibacterial and their capacity for enzymatic production was tested in specific media. Accordingly, 64 yeasts showed enzyme production capacity. From those, six showed good enzyme indexes, 3 for amylase, 2 for cellulase and 1 for protease. All showed at least one hydrolytic enzyme activity for the tested enzymes (amylase, cellulase and protease), which suggested that the yeasts are metabolically active. By sequencing the 26S gene, we identified Naganishia diffluens and Apiotrichum mycotoxinivorans as the species with highest enzyme production activities. Those species showed potential for application as biological catalysts in the biotechnological scope, collaborating in a sustainable way for the development of industrial products.

Soil organic carbon cycling in response to simulated soil moisture variation under field conditions

The combination of extended dry periods and high intensity rainfall, common in the southeastern US, leads to greater variability in soil moisture and consequently increases uncertainty to microbial processes pertinent to soil carbon (C) mineralization. However, field-based findings on soil moisture sensitivity to soil C cycling are very limited. Therefore, a field experiment was conducted in 2018 and 2019 on a soybean (Glycine max L.) cropland in the southeastern US with three soil moisture treatments: drought (simulated using rainout-shelter from June to October in each year), rainfed (natural precipitation), and irrigated (irrigation and precipitation). Soil respiration was measured weekly from May to November in both years. Soil samples were collected multiple times each year from 0–5, 5–15, and 15–30 cm depths to determine microbial biomass C (MBC), extractable organic C (EOC), hydrolytic enzyme activities, and fungal abundance. The cumulative respiration under drought compared to other treatments was lower by 32% to 33% in 2018 and 38% to 45% in 2019. Increased MBC, EOC, and fungal abundance were observed under drought than other treatments. Specific enzyme activity indicated fewer metabolically active microbes under drought treatment compared to rainfed and irrigated treatments. Also, maintenance of enzyme pool was observed under drought condition. These results provide critical insights on microbial metabolism in response to soil moisture variation and how that influences different pools of soil C under field conditions.

Potential of Bacterial Strains Isolated from Ironstone Outcrops Bromeliads to Promote Plant Growth Under Drought Conditions.

Plant growth-promoting bacteria (PGPB) are bacteria that have mechanisms that facilitate plant growth in stress conditions such as drought. The objective of this study was to characterize bacterial strains isolated from bromeliads roots in ironstone outcrops (Urucum Residual Plateau, Mato Grosso do Sul, Brazil) for plant growth-promoting under drought conditions. Firstly, we screened isolates with the presence of 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Then, all isolates were tested for tolerance to drought, exopolysaccharides (EPS) production, indole-3-acetic acid (IAA)-producing abilities, phosphate and zinc solubilization, production of catalase and hydrolytic enzymes (amylase, cellulase, and protease). Germination assay and a pot experiment with maize plants submitted to well-watered and drought conditions were performed with the strains most promising (VBN11 and VBE23). Briefly, Bacillus cereus VBE23 showed in vitro higher ACC deaminase activity (3.83 and 2.52 µmol α-KB mg-1h-1 in non-drought and drought conditions, respectively), tolerance to drought, EPS production and other mechanisms of plant growth promotion: solubilization of phosphate and zinc, ammonia production, catalase activity and production of hydrolytic enzymes (amylase, cellulase, and protease). Inoculation of strain VBE23 in maize seeds submitted to drought conditions showed higher germination concerning uninoculated seeds and inoculated with VBN11. Also, the results indicated that the isolate VBE23 provided higher values of fresh and dry biomass compared to the control of uninoculated treatment and inoculated with VBN11 under drought conditions. This is the first report on the PGPB from ironstone outcrops of Urucum Residual Plateau, Mato Grosso do Sul, Brazil. Thus, this bacterial isolate could be used as a strategy for the facilitation of plant growth in drought environments.

Enhancing methane production from anaerobic digestion of waste activated sludge with addition of sodium lauroyl sarcosinate

In this study, sodium lauroyl sarcosinate (SLS) was used to promote anaerobic digestion of waste activated sludge for producing methane. It was found maximum cumulative methane production increased from 98.1 ± 3.1 to 166.0 ± 4.3 mL/g Volatile Suspended Solids (VSS) with dosage increasing from 0 (control) to 40 mg SLS/g TSS. But the addition of SLS (>10 mg SLS/g Total Suspended Solids (TSS)) resulted in prolonged lag phase time. Microbiological analysis showed that Syntrophobacter and Syntrophomonas both got enriched in reactors fed with SLS. Furthermore, hydrogenotrophic methanogens genus got more enrichment in contrast to acetoclastic methanogens. Mechanism analysis indicated that addition SLS could decrease surface tension, and promote release of organic matters as well as improve activities of hydrolytic enzymes. Besides, SLS could be nearly degraded completely within 3 days, and its degradation intermediates could be further transformed into methane gradually, thus enhancing methane production eventually.

Enhancing PET hydrolytic enzyme activity by fusion of the cellulose–binding domain of cellobiohydrolase I from Trichoderma reesei

The large amounts of polyethylene terephthalate (PET) that enter and accumulate in the environment have posed a serious threat to global ecosystems and human health. A PET hydrolase from PET-assimilating bacterium Ideonella sakaiensis (IsPETase) that exhibits superior PET hydrolytic activity at mild conditions is attracting enormous attention in development of plastic biodegrading strategies. In order to enhance the PET hydrolysis capacity of IsPETase, we selected several polymer-binding domains that can adhere to a hydrophobic polymer surface and fused these to a previously engineered IsPETaseS121E/D186H/R280A (IsPETaseEHA) variant. We found that fusing a cellulose–binding domain (CBM) of cellobiohydrolase I from Trichoderma reesei onto the C-terminus of IsPETaseEHA showed a stimulatory effect on enzymatic hydrolysis of PET. Compared to the parental enzyme, IsPETaseEHA_CBM exhibited 71.5 % and 44.5 % higher hydrolytic activity at 30 ℃ and 40 ℃, respectively. The catalytic activity of IsPETaseEHA_CBM was increased by 86 % when the protein concentration was increased from 2.5 μg/mL to 20 μg/mL. These findings suggest that the fusion of polymer-binding module to IsPETase is a promising strategy to stimulate the enzymatic hydrolysis of PET.

Changing the nutrient composition and enhancing the hydrolytic enzyme activity of citrus pulp residue by cofermentation with Candida utilis and Bacillus subtilis

In this study, citrus pulp residue were treated to improve their nutritional compositions through solid-state fermentation using Candida utilis and Bacillus subtilis. The crude and soluble protein contents increased by 54.83 % and 866.50 %, reaching 242.50 ± 6.50 mg/g and 39.53 ± 1.77 mg/g after fermentation, respectively. The contents of essential amino acids and nonessential amino acids significantly increased by 230 % and 402 %, especially leucine and phenylalanine (8.3 % and 5.1 %, based on total protein). Moreover, antinutritional factors, such as pectin and crude fiber, were reduced by 43.10 % and 20.21 %, respectively. Correlation analysis showed that the activities of fiveenzymes, including acid protease, neutral protease, pectinase,xylanase and cellulase, were significantly correlated with the variation in the contents of soluble protein, total sugars and reducing sugars (p<0.05), indicating that the protein enrichment process was closely related to the changes in organic matter and enzymatic activity. The application of microbial cofermentation provides a new opportunity to improve the nutrients of these low-value organic residue.

Elucidating ROS signaling networks and physiological changes involved in nanoscale zero valent iron primed rice seed germination sensu stricto

Reactive oxygen species (ROS) play pivotal roles during seed dormancy and germination. Metabolically active cells of seeds generate ROS and successful germination is governed by internal ROS contents, maintained within an optimum “oxidative window” by several ROS scavengers. Although ROS was previously considered hazardous, optimum ROS generation in seeds can mediate early seed germination by acting as messengers for cell signaling involved in endosperm weakening, stored food mobilization, etc. Recent reports suggest that nanopriming can expedite seed germination rates and enhance seed quality and crop performances. However, nanoparticle-driven signal cascades involved during seed germination are still unknown. The present study is aimed to explore molecular mechanisms for promoting germination in nanoprimed seeds and to investigate the plausible role of nanoparticle-mediated ROS generation in this process. Here rice seeds were primed with 20 mg L −1nanoscale zero valent iron (nZVI) for 72 h and several biochemical and physiological changes were monitored at different time points (5, 10, 20, 40, 60, and 80 h). To gain insight into roles of ROS in germination rate enhancement, intercellular ROS inhibitor, diphenyleneiodonium (DPI) was taken as another priming agent. Seed priming with DPI impaired seed germination percentage, hydrolytic enzyme activities due to ROS imbalance. On the contrary, seeds primed with both DPI and nZVI could recover from deleterious consequences of DPI treatment. Although DPI impaired intercellular ROS generation, nZVI can generate ROS independently which was confirmed from ROS localization assay. In both nZVI and the DPI and nZVI co-primed sets, significant up-regulation in genes like OsGA3Ox2, OsGAMYB were observed which are responsible for regulating the activity of several hydrolases and mediates efficient mobilization of storage food reserves of seeds. Thus, nZVI priming has potential to regulate intracellular ROS levels and orchestrate all the metabolic activities which eventually up-regulates seed germination rate and seed vigour.

Plateau pika offsets the positive effects of warming on soil organic carbon in an alpine swamp meadow on the Tibetan Plateau

Both climate warming and plateau pika (Ochotona curzoniae) exert considerable impacts on carbon cycling in alpine ecosystems on the Tibetan Plateau. However, the interaction of warming and pika disturbance on soil organic carbon (SOC) dynamics in alpine ecosystems remains largely unknown. Here, we measured plant, soil and microbial properties after four-year warming in a swamp meadow (with or without pika disturbance) on the Tibetan Plateau. Our results showed that in non-pika plots, warming not only increased plant belowground biomass (48%), but also enhanced microbial biomass, hydrolytic enzyme activities, and bacterial functional genes (41–46%). More plant inputs likely outweighed faster microbial decomposition, leading to the accumulation of fast-cycling particulate organic carbon (POC, 49%) and bulk SOC (22%), but not slow-cycling mineral-associated organic carbon (MAOC). In pika-disturbed plots, however, warming did not significantly change plant belowground biomass (which dominates total plant biomass), microbial biomass and hydrolytic enzyme activities. Although bacterial functional genes were suppressed (−40%) and plant aboveground biomass was increased (118%), oxidative enzymes were significantly stimulated (17%), which likely counteracted the higher aboveground plant inputs and led to minor changes in soil carbon pools (SOC, POC and MAOC) with warming. Moreover, bacterial and fungal community structure were significantly altered by pika disturbance, but not warming. Overall, these findings demonstrated that pika disturbance could offset the short-term positive effect of warming on soil organic carbon in the alpine swamp meadow ecosystem.

An in vitro evaluation of the effect of hydroxycinnamic acids on the growth and hydrolytic enzyme production in Fusarium oxysporum f. sp. albedinis

Activation of the phenylpropanoids pathway in date palm (Phoenix dactylifera L.) roots is a key defense mechanism against Fusarium oxysporum f. sp. albedinis (Foa), the causal agent of bayoud. In this study, the effects of four hydroxycinnamic acids (0-5 µm/ml), mainly caffeic acid, p-coumaric acid, ferulic acid and sinapic acid, on fungal biomass production, sporulation and hydrolytic enzymes (protease, cellulase, polygalacturonase and pectinemethyl-esterase) of Foa were investigated. In vitro tests results showed an overall inhibition effect of caffeic and p-coumaric acids compared to ferulic and sinapic acids. Caffeic and p-coumaric acids at 5 µmol/ml had highest inhibition rates of mycelial growth and sporulation ranging from 73 to 80% and 97 to 100%, respectively. For hydrolytic enzyme activities, the inhibition rate of hydoxycinnamic acids tested for protease ranged from 80 to 100%, 63 to 98% for cellulase, 91 to 100% for pectinemethyl-esterase and 59 to 99% for polygalacturonase. Nevertheless, it was found that sinapic acid, at low concentration (0.5 µmol/ml), has no inhibition effect on mycelial growth and hydrolytic enzyme activities. Additionally, the half maximal inhibitory concentration (IC50) has also been determined to compare the different acids effects.

Litter inputs drive increases in topsoil organic carbon after scrub encroachment in an alpine grassland

Shrub encroachment into grasslands can greatly alter soil organic carbon (SOC), nitrogen (N) cycling processes, and carbon (C) pools. However, the effects of shrub encroachment on the soil microbial community and its feedback on the chemical composition of SOC are not well understood in the alpine ecosystems. This study aims to evaluate the impact of the encroachment of the shrubs Salix cupularis and Hippophae rhamnoides on SOC, soil microbial biomass C (MBC) and N (MBN), microbial community structure, and enzyme activities of the topsoil (0–30 cm) and explore the underlying mechanisms in the eastern Tibetan Plateau grasslands of China. We found that while SOC increased under both S. cupularis (16.0 % increase) and H. rhamnoides (23.3 % increase), only the increase in H. rhamnoides was significant in comparison with the adjacent grass soils. The recalcitrant C pool increases were not significant in S. cupularis or H.rhamnoides soils. Additionally, shrub encroachment significantly increased the soil organic N and the activities of N-acetyl-β-glucosaminidase (NAG) and leucine aminopeptidase (LAP). Shrub encroachment significantly increased MBC and MBN, as well as enhanced the total bacteria PLFAs, gram-negtive bacteria PLFAs, arbuscular mycorrhizal fungi, actinomycetes, and hydrolytic enzyme activities, but suppressed the ratio of total fungi to total bacteria PLFAs and phenol oxidase activity in comparison with grassland communities. Redundancy analysis (RDA) showed that litterfall mass, litter N, and root N were the main factors affecting the soil microbial community. Our findings highlight that the encroachment of shrub H. rhamnoides tends to increase soil C sequestration as a result of the high quantities of plant litter input and the changes in the composition of soil microbial communities as well as increased complex C compounds in soil organic matter.

High performance biocatalyst based on β-d-galactosidase immobilized on mesoporous silica/titania/chitosan material

A new support for the immobilization of β-d-galactosidase from Kluyveromyces lactis was developed, consisting of mesoporous silica/titania with a chitosan coating. This support presents a high available surface area and adequate pore size for optimizing the immobilization efficiency of the enzyme and, furthermore, maintaining its activity. The obtained supported biocatalyst was applied in enzyme hydrolytic activity tests with o-NPG, showing high activity 1223 Ug−1, excellent efficiency (74%), and activity recovery (54%). Tests of lactose hydrolysis in a continuous flow reactor showed that during 14 days operation, the biocatalyst maintained full enzymatic activity. In a batch system, after 15 cycles, it retained approximately 90% of its initial catalytic activity and attained full conversion of the lactose 100% (±12%). Additionally, with the use of the mesoporous silica/titania support, the biocatalyst presented no deformation and fragmentation, in both systems, demonstrating high operational stability and appropriate properties for applications in food manufacturing.

Nanopriming with zero-valent iron synthesized using pomegranate peel waste: A “green” approach for yield enhancement in Oryza sativa L. cv. Gonindobhog

Nanopriming is a combination of nanoparticle treatment and a seed dressing technique that can increase seed quality, seedling vigour, yield and also imparts tolerance against biotic and abiotic stress. Here, nano-scale zero-valent iron (G-nZVI) was synthesized using fruit peel waste of Punica granatum L and their formation was validated from XRD and optical spectroscopic techniques. Later, the seeds were primed with G-nZVI at six different concentrations (0, 10, 20, 40, 80, and 160 mg L −1) to determine the dose which is optimum for increasing germination percentage and seedling vigour of rice (Oryza sativa L. cv. Gobindobhog). According to initial results, upon priming seeds with 40–80 mg L −1 G-nZVI highest growth rate was found. The early growth enhancement of seedlings was chiefly attributed to increased ROS generation, higher hydrolytic enzyme activities, and increased iron uptake in germinating seeds upon nanopriming. The effects of nanopriming were carried over to later stages of development. A field experiment was carried out where nanoprimed seeds and traditional hydroprimed control seeds were sown in plots and grown till maturity without the aid of any conventional fertilizers and pesticides and it was found that crop yield and grain nutrient concentrations were higher in nanoprimed sets. Compared to control hydroprimed sets, 1.53 folds higher crop yield was observed upon seed priming with 80 mg L −1 G-nZVI. Thus in the future, G-nZVI can be considered to be a novel low-cost, eco-friendly, food waste-derived seed treatment agent that has immense potential in increasing rice yield.

The Occurrence of Triple Catalytic Characteristics of Yeast Lipases and Their Application Prospects in Biodiesel Production from Non-Edible Jatropha curcas Oil in a Solvent-Free System.

Extracellular and cell-bound lipase-producing yeasts were isolated from the palm oil mill wastes and investigated for their potential uses as biocatalysts in biodiesel production. Twenty-six yeast strains were qualitatively screened as lipase producers. From those yeast strains, only six were selected and screened further for quantitative lipase production.The phylogenetic affiliations of the yeast strains were confirmed by investigating the D1/D2 domains of 26S rDNA and ITS1-5.8S-ITS2 molecular regions of the six yeast strains selected as potent lipase producers. The three yeast strains A4C, 18B, and 10F showed a close association with Magnusiomyces capitatus. Two yeast strains (17B and AgB) had a close relationship with Saprochaete clavata, whereas the strain AW2 was identified as Magnusiomyces spicifer. Three main catalytic activities of the yeast lipases were evaluated and Magnusiomyces capitatus A4C, among the selected lipase-producing yeasts, had the highest extracellular lipolytic enzyme activity (969U/L) with the cell-bound lipolytic enzyme activity of 11.3U/gdm. The maximum cell-bound lipolytic activity (12.4U/gdm) was observed in the cell-bound lipase fraction produced by Magnusiomyces spicifer AW2 with an extracellular lipolytic enzyme activity of 886U/L. Based on the specific hydrolytic enzymatic activities, the cell-bound lipases (CBLs) from the three yeast strains M. capitatus A4C, M. spicifer AW2, and Saprochaete clavata 17B were further investigated for biodiesel production. Among them, the CBL from M. spicifer AW2 synthesized the most FAME (fatty acid methyl esters) at 81.2% within 12h indicating that it has potential for application in enzymatic biodiesel production.

Bud break accompanies with the enhanced activities of hemicellulase and pectinase and the mobilization of cell wall thickenings in Persian walnut bud scales

The endo-dormant bud scales of walnut have storage parenchyma cells with thickened walls. During bud dormancy release, cell wall hydrolytic enzymes mobilize pectin and hemicellulose reserves of these cells to fuel bud break. Cell wall hydrolytic enzymes might define specific stages of bud dormancy release. Bud dormancy release is important in woody plants as it is linked to final biomass and yield. This process requires enzyme activities which affect the bud cell wall physico-chemical properties, however, little information is available. Accordingly, the activities of some cell wall hydrolytic enzymes were studied during endo-dormancy release in lateral buds of two Persian walnut (Juglans regia L.) cultivars having low (‘Serr’) and high (‘Hartley’) chilling requirements (CRs). Buds were collected monthly from the leaf shedding stage (November) till bud break and used for enzymatic analysis. In both cultivars, the activities of 1,4-β-D-glucanase, xylanase, mannanase and pectinase increased during dormancy release. In ‘Serr’, first rises in mannanase and pectinase activities occurred before transition to eco-dormancy (January) and the second rises occurred before bud break (March). Similarly, in ‘Hartley’, first rise in mannanase activity observed before transition to eco-dormancy (February) and the second rise before bud break (April). ‘Serr’ buds also displayed significant increase in the activities of hemicellulases and pectinase earlier than ‘Hartley’, however, the latter showed quantitatively higher means for the enzymatic activities. Endo-dormant bud scales had very thick-walled storage parenchyma cells which turned into thinner-walled ones during bud break, suggesting cell wall polysaccharide mobilization by hemicellulases and pectinases. Thus, the activation of cell wall hydrolytic enzymes during endo-dormancy release may contribute to the bud scale cell wall carbohydrate reserve mobilization and/or growth-associated wall relaxation in preparation for bud break. Furthermore, buds from low CR plants may show earlier activation of cell wall-loosening mechanisms during dormancy release.

Changes in the structural components of the mucous membrane and plasma proteins of small intestine enterocytes in fetuses of cattle

The interrelationships of morphological changes of the mucosa of the large intestine with the dynamics of enzyme activity at different poles of enterocytes of cattle during the fetal period of ontogenesis are shown and analyzed. The work was performed on Holstein cattle aged two to nine months. The activity of hydrolytic and transport enzymatic systems in the basolateral membrane of cattle enterocytes depends less on the morphometric parameters of the large intestine than in the apical membrane. It is proved that during the fruitful period of ontogenesis there are dynamic transformations of enzyme systems of enterocytes of the large intestine of cattle which are connected with morphological changes of the mucous membrane of the large intestine. The activity of hydrolytic and transport enzymes in different domains of the plasma enterocytes of fetal cattle is interrelated with the morphometric parameters of the colon, in particular. the activity of alkaline phosphatase, γ-glutamyltransferase, Na+, K+-ATPase, Ca2 +, Mg2 +-ATPase and Mg-ATPase in the apical membrane of enterocytes is inversely related to the thickness of the intestinal wall with villi and the mucous membrane of the cavity (P ≤ 0.01–0.001). A significant correlation was found between the activity of alkaline phosphatase, γ-glutamyltransferase, Na+, K+-ATPase, Ca2 +, Mg2 +-ATPase and Mg-ATPase in the apical membrane of enterocytes with villi height (P ≤ 0.05). The activity of hydrolytic and transport enzymatic systems in the basolateral membrane of bovine fetal enterocytes depends to a lesser extent on the morphometric parameters of the large intestine than in the apical membrane. In particular, only the activity of alkaline phosphatase and γ-glutamyltransferase is inversely related to the thickness of the intestinal wall with villi and the mucous membrane of the jejunum with villi (P ≤ 0.01–0.001). The activity of transport enzymes is directly related to the morphometric parameters of the colon (P ≤ 0.01). The activity of these enzymes in the basolateral membrane does not significantly depend on the width of the villi, but is dependent on their height.