Mixed Substrate Research Articles

\(\textit{In vitro}\) regeneration and acclimatization of \(\textit{Anthurium scherzerianum }\)schott plants

This study investigated the effects of different PGRs on in vitro plant regeneration of Anthurium scherzerianum Schott and acclimatization in the ex vitro stage. Depending on the objective of each experiment, the in vitro shoots were induced from callus cultured on a modified Murashige and Skoog (MS) medium containing cytokinins and auxins. Results showed that 90% of leaf explants and 48% of petiole explants produced callus. A half-strength MS medium supplemented with 1.0 mg/l Kinetin (KIN) gave the best result for shoot regeneration and 1.5 mg/l α-naphthalene acetic acid (NAA) is suitable for rooting of A. scherzerianum. The culture vessel having a hole on the cap gave the best result on the growth of A. scherzerianum plantlets. After 90 days transferred to the greenhouse, in vitro plantlets which were cultivated on a mixed substrate of coconut fiber powder: rice husk ash: compost (6:3:1, respectively) had a better growth (shoot length of 8.88 cm, root length of 3.44 cm) than those on another mixed substrate of coconut fiber powder: compost (9:1, respectively).

Exon 2-mediated deletion of Trem2 does not worsen metabolic function in diet-induced obese mice.

Triggering receptor expressed on myeloid cells 2 (Trem2) is highly expressed on myeloid cells and is involved in cellular lipid homeostasis and inflammatory processes. Trem2 deletion in mice (Trem2-/- ) evokes adipose tissue dysfunction, but its role in worsening obesity-induced metabolic dysfunction has not been resolved. Here we aimed to determine the causal role of Trem2 in regulating glucose homeostasis and insulin sensitivity in mice. Nine-week-old male and female littermate wild-type (WT) and Trem2-/- mice were fed a low- or high-fat diet for 18weeks and phenotyped for metabolic function. Diet-induced weight gain was similar between genotypes, irrespective of sex. Consistent with previous reports, we find that loss of Trem2 causes massive adipocyte hypertrophy and an attenuation in the lipid-associated macrophage transcriptional response to obesity. In contrast to published data, we find that loss of Trem2 does not worsen metabolic function in obese mice. No differences in intraperitoneal glucose tolerance (ipGTT), oral GTT or mixed meal substrate control, including postprandial glucose, non-esterified fatty acids, insulin or triglycerides, were found between WT and Trem2-/- animals. Similarly, no phenotypic differences existed when animals were challenged with stressors on metabolic demand (i.e. acute exercise or environmental temperature modulation). Collectively, we report a disassociation between adipose tissue remodelling caused by loss of Trem2 and whole-body metabolic homeostasis in obese mice. The complementary nature of experiments conducted gives credence to the conclusion that loss of Trem2 is unlikely to worsen glucose homeostasis in mice.

Three Pleurotus mushroom species cultivated in a mixed Phragmites australis substrate differ in nutrient utilization capacity

Phragmites australis (common reed) distributed in brackish or saline wetlands, with significant ecological and economic values. Cultivating edible fungi is an exciting and developing field in reed utilization, and proven to be a viable technology. However, it remains unclear how nutrient utilization efficiency differs between mushroom species. Globally, Pleurotus ostreatus is the easily and most bagged cultivated mushroom. Therefore, three Pleurotus species were used to investigate the nutrient utilization of reed. A 2-year cultivation experiment was conducted during which three mushroom flushes were obtained. A significant difference in fresh weight was only found in the first harvest of the three mushroom species. A comparison of fruit quality characteristics of the first flush revealed the highest levels to be as follows, respectively: fresh weight in P. ostreatus (57.4%), total sugar content in P. eryngii (69.0%), and crude protein (28.3%) and amino acids levels in P. citrinopileatus. Glusate and histidine were the main amino acid components in P. citrinopileatus. Besides, iron and zinc could be heavily enriched in P. ostreatus. Heavy metals were the highest in P. ostreatus, but they were below the National Food Safety Standards. Generally, P. ostreatus had the highest biological efficiency, while P. eryngii had the highest carbon utilization and P. citrinopileatus had the highest nitrogen utilization efficiency.

Tamarindus indica seed induced tannase production from Aspergillus niger

Introduction and Aim: Tannase an inducible extracellular microbial enzyme is extensively produced by different fermentation techniques and finds wide applications in food, pharmaceutical and textile industries. The present investigation focused on tannase production from Aspergillus niger through submerged (SmF) and solid-substrate fermentation (SSF) using different media. The enzyme was also induced using tamarind seeds. Methods and Materials: Aspergillus niger was grown in various submerged media such as Tannase screening broth (TSB), Czapek Dox broth (CDB), Sabouraud’s Dextrose broth (SDB) and Potato Dextrose broth (PDB). Among solid substrates wheat bran, ground nut cake, coconut cake and tamarind seed powder used individually and in mixed form. Results: In SmF, the highest tannase activity of 713.6 U/ml was found in TSB, followed by CDB (590.6 U/ml), SDB (465.6 U/ml) and PDB (424.8 U/ml). In all media highest activity was on 4th day while in SDB on 6th day of incubation. Tannase production was also carried out in CDB supplemented with 2% processed tamarind seeds to test for its induction, where the highest (936 U/ml) activity was in raw seeds than in processed seeds. SSF in mixed substrates showed highest activity of 1708.6 U/gds followed by 1278.0, 986.5, 826.3 and 723.6 U/gds in tamarind seeds, wheat bran, ground nut cake and coconut cake, respectively. Conclusion: Tannase enzyme is found to be induced by raw tamarind seed supplemented submerged medium than with processed seeds. In SSF with tamarind seed showed the highest tannase activity indicating that the tannic acid present in raw seeds serve to induce Aspergillus niger for increased production of tannase enzyme.

Optimized cell growth and poly(3-hydroxybutyrate) synthesis from saponified spent coffee grounds oil

Spent coffee ground (SCG) oil is an ideal substrate for the biosynthesis of polyhydroxyalkanoates (PHAs) by Cupriavidus necator. The immiscibility of lipids with water limits their bioavailability, but this can be resolved by saponifying the oil with potassium hydroxide to form water-soluble fatty acid potassium salts and glycerol. Total saponification was achieved with 0.5 mol/L of KOH at 50 °C for 90 min. The relationship between the initial carbon substrate concentration (C0) and the specific growth rate (µ) of C. necator DSM 545 was evaluated in shake flask cultivations; crude and saponified SCG oils were supplied at matching initial carbon concentrations (C0 = 2.9–23.0 g/L). The Han-Levenspiel model provided the closest fit to the experimental data and accurately described complete growth inhibition at 32.9 g/L (C0 = 19.1 g/L) saponified SCG oil. Peak µ-values of 0.139 h−1 and 0.145 h−1 were obtained with 11.99 g/L crude and 17.40 g/L saponified SCG oil, respectively. Further improvement to biomass production was achieved by mixing the crude and saponified substrates together in a carbon ratio of 75:25% (w/w), respectively. In bioreactors, C. necator initially grew faster on the mixed substrates (µ = 0.35 h−1) than on the crude SCG oil (µ = 0.23 h−1). After harvesting, cells grown on crude SCG oil obtained a total biomass concentration of 7.8 g/L and contained 77.8% (w/w) PHA, whereas cells grown on the mixed substrates produced 8.5 g/L of total biomass and accumulated 84.4% (w/w) of PHA.Key points• The bioavailability of plant oil substrates can be improved via saponification.• Cell growth and inhibition were accurately described by the Han-Levenpsiel model.• Mixing crude and saponified oils enable variation of free fatty acid content.

Production of polyhydroxyalkanoates by a novel strain of Photobacterium using soybean oil and corn starch

Photobacterium sp. TLY01, a novel strain of Photobacterium genus isolated from an oil field, was found to allow the accumulation of polyhydroxyalkanoates (PHAs) from a series of sustainable substrates, including glycerol, carbohydrates, plant oils, and volatile fatty acids. Interestingly, Photobacterium sp. TLY01 could effectively utilize plant oils or corn starch to synthesize poly-3-hydroxybutyrate (PHB). When propionate or valerate was added as secondary carbon source, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was produced. In fed-batch fermentation, the strain produced 53.89 g/L PHB using glycerol. When soybean oil and valerate were used as joint substrates, PHBV titer reached 16.28 g/L in bioreactor cultures. Furtherly, tryptone and yeast extract in culture medium were replaced with corn steep liquor to support PHA production. At last, a mixed substrate containing waste cooking oil, corn starch, and valerate was employed for PHBV production, achieving a titer of 4.01 g/L. The results indicated that Photobacterium sp. TLY01 is a promising strain for PHA production with low-cost sustainable substrates.

Exploring magnetic field treatment into solid-state fermentation of organic waste for improving structural and physiological properties of keratin peptides

This study systematically investigated the effects of a low-intensity magnetic field on the influence of keratinase activity, peptide yield, and structural and functional properties of peptides produced during solid-state fermentation (SSF) of mixed organic substrates (chicken feather powder and okara) using a mutant strain of Bacillus licheniformis. Initially, the magnetic field-assisted SSF (MSSF) conditions were optimized, which provided the optimized conditions as the number of treatments 3 at every 24 h (24, 48, and 72 h) with 4 h holding time at 120 Gs of magnetic intensity (mI). Under the optimum conditions, keratinase activity and peptide production increased by 10.31% and 13.77%, respectively. Further, in order to evaluate the influence of magnetic field treatment on the peptides, MSSF experiments were done under different mI conditions (40, 80, 120, and 160 Gs), followed by the evaluation of the structural changes of the extracted peptides. The structural analysis revealed that mI had a significant impact on the keratin surface. In contrast, secondary structure analysis confirmed the unfolding of the peptide with decreased α-keratin and increased β-keratin, thereby boosting the bioactive properties of the peptides. The highest hydroxyl free radical (.OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and Fe2+ chelating rates (56.55, 71.36, and 50.72%, respectively) were found at 120 Gs, which were insignificant with the results at 160 Gs. Therefore, MSSF has a positive effect on the proteolysis mechanism, which can increase bioactive peptide production from keratin.

Adsorption and decomposition of ZDDP on lightweight metallic substrates: Ab initio and experimental insights

Lightweight alloys substitute steel in a wide range of industrial applications. It is still unclear whether the lubricant additives currently employed to reduce friction of sliding metallic parts are also efficient on non-ferrous substrates. In particular, the functionality of zinc dialkyldithiophosphates (ZDDPs) in contact with Al- and Mg-containing alloys still needs to be understood. In this work, we describe the properties of ZDDP at Al(111), Al(001), Al(331), Mg(0001) and Mg17Al12 surfaces and interfaces. Our calculations indicate that molecular fragments originated from ZDDP chemisorb more strongly on the intermetallic phase Mg17Al12 with respect to aluminum and magnesium, due to the higher surface energy of the mixed substrate. Ab initio molecular dynamics simulations show that the kinetics of the additive decomposition is significantly different on Al and the mixed phase. These results are supported by atomic force microscopy sliding tests, which revealed that the tribofilm formation is observed only on the latter substrate. This work suggests that the tribological performance of lightweight alloys can be enhanced by increasing the additive-surface chemical interactions.

An Experimental Study of Paddy Drainage Treatment by Zeolite and Effective Microorganisms (EM)

Eco-ditch systems have increasingly been designed and applied as a strategy to decrease the risks of water eutrophication and contamination pollution for sustainable agriculture. The main goal of this study was to evaluate the water quality of eco-ditch substrates amended with zeolite and Effective Microorganisms (EM), such as pH, dissolved oxygen concentration (DO), ammonium nitrogen concentration (NH4+-N), and nitrate nitrogen concentration (NO3−-N). Laboratory experiments were conducted with four single substrates (soil, none substrates, natural zeolite, and zeolite loaded with EM bacteria) and two mixed substrates (soil and varying proportions of the additives, 0, 5 and 15%, m/m). Results showed that the concentration of NH4+-N was decreased with the increasing rates of additives, and zeolite loaded with EM bacteria had the highest nitrogen removal rate (97.90%) under static experimental condition. The application rate of 15% zeolite loaded with EM bacteria on the eco-ditch exerted a better effect on NH4+-N and NO3−-N removal without pH reduction, decreased by 87.19% for NH4+-N and 30.33% for NO3−-N, respectively. Path analysis showed that zeolite addition had a rapid effect (path coefficient = −0.972) on free NH4+-N ions adsorption in early 1–3 days, then EM loaded at zeolite further decreased NH4+-N (path coefficient = −0.693) and NO3−-N (path coefficient = −0.334) via bacterial metabolism. Based on the results, the applications of natural zeolite and Effective Microorganisms (EM) at an appropriate rate (15%, m/m) can significantly improve water quality of paddy drainage via exerting effects on nitrogen removal.

Foraging microhabitat selection of Spoon-billed Sandpiper in the Upper Gulf of Mottama, Myanmar

Spoon-billed Sandpiper ( Calidris pygmaea ) is Critically Endangered, declining 9% per year since 2009; although important wintering sites have been identified, little is known about why particular sites are selected. The Gulf of Mottama, Myanmar, supports perhaps 60% of the global population in winter. Our objective was to identify macrohabitat and microhabitat characteristics of Spoon-billed Sandpiper foraging locations. We considered 1) location (relative to distance to the main channel of the gulf), 2) temporal patterns (relative to the tide cycle), 3) physical substrate characteristics and 4) possible food sources. Spoon-billed Sandpipers were observed at 26 foraging locations during the study (November 2019-March 2020). The sandpipers were found more frequently on mixed sand-mud substrate, similar to over-wintering sites in Bangladesh, and while it is likely that the mixed sand-mud substrate was generally further from the main channel than the pure sand substrate, presumably due to tidal action, we found no evidence that Spoon-billed Sandpiper locations were associated with the tide cycle. Logistic regression models indicated that foraging locations were associated with shallow surface puddles, compared to random locations. The mixed sand-mud substrate supported more polychaetes relative to crabs or insect larvae, the three most common prey types in our 442 benthos samples used to assess prey availability. Our results reinforce the point that Mottama needs to be protected as an intact functioning estuary and key site for Spoon-billed Sandpiper and other threatened shorebirds. Although we have identified some characteristics of foraging sites associated with Spoon-billed Sandpiper at Mottama, we still lack understanding as to whether and how potential prey is driving site selection and how these characteristics vary among wintering sites.

Adaptability of Broussonetia papyrifera to sewage sludge and its characteristics of nutrient and heavy metal uptake and accumulation

Broussonetia papyrifera, an important fast-growing economic tree species in China, has the advantages of strong adaptability, high-biomass, and high bioconcentration of heavy metals. Sewage sludge contains a great deal of nutrients and heavy metals. Planting B. papyrifera with sewage sludge can achieve the goals of sewage sludge remediation as well as resources production of B. papyrifera. A pot experiment was conducted to investigate growth, uptake and accumulation of nutrient and heavy metal in different organs (root, stem, leaf) of B. papyrifera, with treatments of control (lateritic red soil), 50% sewage sludge (mixed substrates of 50% sewage sludge and 50% lateritic red soil based on weight) and 100% sewage sludge. The comprehensive evaluation of capacity of uptake and accumulation was also carried out by principal component analysis and membership function. The results showed that B. papyrifera could grow normally in both 50% and 100% sewage sludge substrates, with higher plant height and biomass than that in the control, especially in 100% sewage sludge substrate. The quality index in 100% sewage sludge substrate (1.02) was 4.3 times and 2.4 times as that of the control and 50% sewage sludge substrate, respectively. The content of N in different organs and P in stem increased significantly in both 50% and 100% sewage sludge substrates. The content of K in stem and leaf was significantly decreased in 100% sewage sludge substrate, which were significant lower than that of control. The uptake of heavy metals such as Cu, Zn, Pb, Cd, Ni for B. papyrifera were mainly through roots. There was positive correlation between the content of heavy metals in root and sewage sludge ratio. The content of Pb and Cd in leaves were lower than the limit value of Hygienic Standard For Feeds (GB 13078-2017). The capacity for absorption and accumulation of Cd was better than that of other heavy metals. Compared with the control, rootretention rates of Zn, Pb and Cd significantly increased in both 50% and 100% sewage sludge substrates (57.8%-85.8%), while Cu and Ni significantly increased in 100% sewage sludge substrate (67.5% and 74.8%). Nutrient and heavy metal accumulations in total plant in both 50% and 100% sewage sludge substrates were significantly higher than that in the control, with 100% sewage sludge substrate being significantly higher than that in 50% sewage sludge substrate. Compared with 50% sewage sludge substrate, the increment rates of nutrient and heavy metal accumulations in different organs as well as total plants in 100% sewage sludge substrates were greatly increased. The rank of comprehensive evaluation scores of adaptability, element uptake and accumulation was in an order: 100% sewage sludge substrate (0.848) > 50% sewage sludge substrate (0.344) > control (0.080). With good adaptability to sewage sludge, B. papyrifera could grow normally in sewage sludge andeffectively absorb and fix nutrients and heavy metals. It is feasible to plant B. papyrifera into the sewage sludge for remediation of sewage sludge and resource production.

Non-Vent Megafaunal Communities on the Endeavour and Middle Valley Segments of the Juan de Fuca Ridge, Northeast Pacific Ocean

There has been increasing interest in mining polymetallic sulfide deposits at deep-sea inactive hydrothermal vents, leading to the development of regulations to minimize risk to the marine environment. While an extensive body of literature exists on the ecological communities at active vents, fauna at inactive hydrothermal vents and the vent periphery are poorly described and their vulnerability to disturbance is unknown. We examined patterns in abundance of non-vent epibenthic megafauna on two segments of the Juan de Fuca Ridge, Northeast Pacific Ocean. Video footage was collected by the remotely operated vehicle ROPOS during four dives at the Endeavour Segment and two dives at Middle Valley in August 2016. At the Endeavour Segment, the substrate is characterized predominantly by basalt and edifices of hydrothermal sulfide that range in hydrothermal activity from inactive to vigorous, high-temperature venting. In contrast, Middle Valley is heavily sedimented and most hydrothermal activity is low-temperature diffuse flow. While inactive substrates at both sites harboured slow-growing sessile fauna, the dominant members of the community differed between sites. At Endeavour, the most abundant morphotaxa included rossellid vase sponges, alcyonacean corals, and crinoids. Estimated richness and total abundance of morphotaxa was higher on hard substrates than sedimented substrates and highest on inactive chimneys. At Middle Valley, the most abundant morphotaxa included antipatharian corals, anemones, and ascidians. Species richness was higher on inactive chimneys and mixed substrates than sediment. The abundance of some megafauna varied with proximity to active vents. At Endeavour, deep-water corals were nearly absent within 25 m of active chimneys and very few occurred between 26 and 50 m from active chimneys. Rossellid vase sponges were in low abundance within 25 m of active chimneys but were more abundant than corals at 26-50 m from active chimneys. This project contributes baseline data on megafaunal assemblages on inactive hydrothermal vents and can provide the basis for more focused research on the structure and function of inactive vent ecosystems.

Nitrilase gene detection and nitrile metabolism in two bacterial strains associated with waste streams in Lagos, Nigeria

BackgroundThe use of nitrile compounds is usually high, particularly in chemical industries, which calls for serious concern because of their relevance to the environment. The essential role of nitrilases in the bioremediation of harmful nitriles from environmental wastes cannot be overemphasized. The study aimed to unveil the biodegradative potentials of bacterial strains associated with the degradation of nitrile pollutants.MethodsBacterial strains capable of utilizing glutaronitrile as the sole source of carbon and nitrogen were isolated from solid waste leachates by a selective enrichment culture technique. The test organisms were grown in mineral salts medium (MSM), and the metabolic products were determined using gas chromatography-flame ionization detection (GC-FID). The nitrilase gene was amplified by polymerase chain reaction (PCR) and by using appropriate primers.ResultsThe growth studies showed that the test organisms grew on the two nitriles. The doubling times of 12.16 d and 9.46 d (specific growth rate, µ=0.082 d−1, 0.106 d−1) were obtained for each pure culture of Bacillus sp. srain WOD8 and Corynebacterium sp. srain WOIS2 on glutaronitrile (as single substrate), respectively. While the same strains had doubling times of 11.11 d and 10.00 d (µ=0.090 d−1, 0.100 d−1) on benzonitrile (as single substrate). However, the mixed culture (comprising the two strains) had doubling times of 7.40 d and 7.75 d (µ=0.135 d−1, 0.129 d−1) on glutaronitrile (as single and mixed substrates), respectively. While doubling times of 8.09 d and 8.71 d (µ=0.124 d−1, 0.115 d−1) were obtained for the same mixed culture on benzonitrile (as single and mixed substrates). Based on gas chromatographic analysis, the residual glutaronitrile concentrations at day 16 for strains WOD8 and WOIS2 were 35.77 g L−1 (72.2%) and 9.30 g L−1 (92.5%), respectively, whereas the residual benzonitrile concentrations for the same strains were 27.39 g L−1 (78.8%) and 13.79 g L−1 (89.2%), respectively. For the mixed culture, residual glutaronitrile and benzonitrile concentrations at day 16 were 13.40 g L−1 (88.5%) and 10.42 g L−1 (91.5%), respectively, whereas for the mixed substrates (glutaronitrile and benzonitrile), 7.21 g L−1 (91.7%) and 4.80 g L−1 (94.2%) of residual glutaronitrile and benzonitrile concentrations were obtained by the same consortium. The gene for nitrilase involved in nitrile degradation was detected in the genome of the bacterial strains. The amplified nitrilase gene gave PCR products of sizes 1400 bp and 1000 bp, as expected for strains WOD8 and WOIS2, respectively. 4-Cyanobutyric acid (4CBA), glutaric acid (GA), and benzoic acid (BA) were obtained as metabolites following nitrile degradation in vitro.ConclusionThese results revealed that strains WOD8, WOIS2 and the mixed culture (consisting of the two strains) have proven to have the capacity to metabolize nitriles (glutaronitrile and benzonitrile) as the carbon and nitrogen sources. However, the mixed culture had higher nitrile degradation rate as compared to each pure culture of the two test organisms. These results also provide insight into the evolutionary genetic origin of a nitrilase gene that encodes an enzyme that catalyzes nitrile degradation in these strains. Hence, the bacterial strains that harbor this kind of gene may be used as promising biological agents for the remediation of sites polluted with nitriles, thereby opening new perspectives for encouraging data for a bioremediation bioprocess.

Synthesis of intracellular polyhydroxyalkanoates (PHA) from mixed phenolic substrates in an acclimated consortium and the mechanisms of toxicity

Polyhydroxyalkanoates (PHA) are a class of intracellular storage polymers with the potential to supplement/replace petroleum-based plastics. Production of PHA from waste organics can reduce its cost, but toxic carbon sources such as simple aromatics are seldom used. This study investigates the feasibility of mixed toxic phenolics as substrates, utilizing a phenol-acclimated consortium of high PHA accumulation capability. Phenol was employed as the main feedstock, and four kinds of mono- and di-chlorinated phenols (CPs) were individually mixed with it as possible impurities. The inclusion of CPs was found to reduce substrate removal and PHA accumulation rates, compared to phenol alone. The degree of inhibition was positively-correlated with CP concentration, but the mechanisms differed. 2- and 3-chlorinated phenols formed dark, toxic, dead-end products; 4-chlorinated phenol (4-CP) appeared to exert competitive inhibition; and 2,4-dichlorinated phenol acted like an inert component. Transformation pathway study discovered that phenol was degraded via meta-cleavage, while 2- and 3-CPs were transformed into 3-chlorocatechol as the intermediate. FTIR, DSC, NMR, HPLC and elemental analysis were carried out to characterize the extracted polymer. The results show that phenol was converted to poly(3-hydroxybutyrate), while the inclusion of mono-chlorinated phenol promoted the production of PHA containing 3-hydroxyvalerate (3HV) monomers. A recovery test after mild CP exposure found that the affected biomass was able to resume phenol degradation and PHA synthesis immediately after simple aeration, indicating its robustness and applicability in a real industrial setting.

Assessment of potential biotoxicity induced by biochar-derived dissolved organic matters to biological fermentative H2 production

Biochar is a widely used antecedent for improving bio‑hydrogen production. However, little is known about the impact of biochar-derived dissolved organic matter (DOM) on the performance of fermentative bio-H2 production. Herein, we evaluated the impact of biochar-derived DOM on the fermentation performance of hydrogen-producing microflora. The pyrolysis temperature of biochar affected the DOM composition, with lower pyrolysis temperatures showing more serious inhibition on H2 accumulation. When biochar was pyrolyzed at 500 °C, DOM prolonged the fermentation period and decreased H2 production from 1330.41 mL L−1 to 1177.05 mL L−1 compared to the control group. The xylose utilization in mixed substrate decreased from 29.72% to 26.41%, which is not favorable for practical applications where lignocellulosic biomass is used as a substrate. Otherwise, DOM caused a 6% reduction in microbial biomass accumulation and less soluble metabolites formation. The potential mechanism of DOM inhibiting bio‑hydrogen production was verified by identifying an increase in reactive oxygen species (ROS) level (178.2%) and the microbial community shifted to containing fewer hydrogen-producing strains. The finding prompts a more precise design of biochar applications in fermentation systems to alleviate the potential hazards and maximum the fermentation performance, not limited to fermentative hydrogen production system.

Secondary metabolite changes in Maymars juniper cuttings (Juniperus sabina) under different treatments of propagation (IBA, substrate and harvest time of cutting)

The Endemic Juniper of Maymars (Juniperus sabina) is one of the most valuable plants in forested areas. The objectives of this experiment were: I) to determine the best conditions for stem cutting propagation of this species, and II) to examine changes in some of the secondary metabolites during the four months (the first of each season): January, April, July, and October, after rooting of cuttings. The research was done with the treatment of five levels of Indole Butyric Acid, including: 0, 1000, 2000, 4000, and 8000 ppm in four rooting substrates, including perlite, perlite-cocopeat (1:1), pumice, and a mixed rooting substrate (sand, perlite, cocopeat, vermicompost, and potash; 1:1:1:1:1) in the four seasons of the year, with stem cuttings having an average length of 15 cm. The best treatment with more than 50% rooting was seen in April at levels of 4000 and 1000 ppm, and the best substrate was perlite cocopeat. Using lower levels of IBA led to a reduction in total phenol content in the cuttings during the rooting period. The flavonoid content of the cuttings varied across different seasons. Based on these results, we recommend this way of propagation for Juniperus sabina production. This propagation method takes less time in comparison with sexual propagation from seed.

Growth Characteristics by Plug Tray Cell Size, Soil Type, and Fertilizer Concentration for Plug Seedling Production of Veronica pusanensis Y.N. Lee

Background and objective This study was conducted to establish a stable seedling production system for Veronica pusanensis Y.N. Lee, a plant that is endemic to the Korean Peninsula and is a critically endangered species, distributed along the coast of Busan, Korea. Methods In order to investigate the plug cell size (72, 128, 200 cells), soil type (commercial substrate, and mixed substrates with peat moss and perlite at ratios of 1:1, 3:1, and 4:1), and fertilizer concentration (Peters 0, 500, 1,000, and 2,000 mg·L−1) conditions, the plug tray was filled with soil and seeds were sown. The sown trays were placed in the growth chamber (25°C, 70% RH, PPFD 100 μmol·m−2·s−1) for three repetitions per treatment. Results There was no difference in the growth of seedlings according to plug cell size. Therefore, it appears to be economically superior to produce seedlings in a 200-cell plug tray. In soil type, the seedling growth increased as the ratio of peat increased, but leaf chlorosis occurred from the 7th week after sowing. Examining the growth of seedlings based on fertilizer concentration, the greatest increase in growth was found to have occurred in the 1,000 mg·L−1 treatment. Conclusion Therefore, for the production of V. pusanesis seedlings, it was noted that when mixed soil with peatmoss and perlite at a ratio of 4:1 is filled in 200-cell plug trays, and the seedlings are fertilized with Peters 1,000 mg·L−1 once a week, growth will increase the most, demonstrating excellent cost-effectiveness. However, to mass-produce high-quality seedlings in a short period, it will be necessary to use a plug tray smaller than 200 cells or to conduct various fertilization composition studies.

Metabolomics combined with physiological and transcriptomic analyses reveal regulatory features associated with blueberry growth in different soilless substrates

The objective of this study was to evaluate the effects of soilless substrate mixtures on blueberry seedling growth under greenhouse conditions and to determine the optimal growth media for soilless blueberry (Vaccinium australe) cultivation. Trials were carried out with two-year-old blueberry seedlings from April to August 2021. Three mixed substrates (PB: peat and bark (1:1, v/v), PR: peat and rice husk (1:1, v/v), and BR: bark and rice husk (1:1, v/v)) were investigated. The results showed that the plant height, stem diameter and chlorophyll content were much higher in PB and PR than in BR. The PB and PR substrates triggered antioxidant system activity and exerted marked positive effects on blueberry seedling growth. The total flavonoid content was greatly increased in the PB group compared with the other two groups. Most element contents were greatly increased with BR compared with PB and PR. Furthermore, metabolomic and transcriptomic analyses revealed the critical responses of metabolic pathways to different substrate treatments in blueberry leaves collected in June. Overall, the metabolomic data revealed 757 metabolites with decreased levels and 1383 metabolites with increased levels. The levels of multiple prenol lipids, flavonoids, organooxygen compounds, carboxylic acids and derivatives were changed. “Flavonoid biosynthesis” was the most significantly enriched pathway and may be closely related to blueberry growth. Integrated transcriptomic and metabolomic data suggested that the expression of 4 DEGs, VcPAL, VcHCT, VcF14G24.3, and VcCHS, was strongly correlated with flavonoid biosynthesis. This work provides insights for elucidating the mechanisms that mediate the growth adaptability of blueberry cv. ‘Zhaixuan 7’ in different substrates.

Effects of biochar as a peat-based substrate component on morphological, photosynthetic and biochemical characteristics of Rhododendron delavayi Franch.

Biochar could be a promising peat substitute for horticultural plant production. We evaluated the feasibility of rice husk biochar (RHB) and wood chip biochar (WCB) as a peat-based substrate component for the cultivation of Rhododendron delavayi Franch., that is an ornamental dwarf tree species. A pot experiment was conducted to test the effects of RHB and WCB treatments at five application rates ( 0, 10, 20, 30, and 40% by volume) on morphological, photosynthetic and biochemical characteristics of R. delavayi. The substrate properties, plant growth, root traits, photosynthetic and biochemical parameters were analyzed. The addition of 20% WCB or 30-40% RHB enhanced the growth and photosynthetic activity of R. delavayi seedling, including increased plant height, numbers of leaves, leaf area, root surface area and root tip numbers, as well as improved total chlorophylls content and net photosynthetic rate. The addition of 40% RHB significantly increased the contents of carotenoids, polyphenols and anthocyans, indicating an enhanced antioxidant activity of R. delavayi seedlings. The mixed substrates (20% WCB, 30% RHB and 40% RHB) all have balanced aeration porosity and water holding porosity, suitable pH and electrical conductivity, and increased plant nutrient supply (especially K, Fe and Mn). However, the 40% WCB substrate depressed seedlings growth and reduced total chlorophylls content and net photosynthetic rate. The negative effects were linked to its low water holding porosity, high alkalinity and salinity, as well as high content of phytotoxic compounds, such as polycyclic aromatic hydrocarbons and volatile matter. In conclusion, a peat-based substrate containing 20% WCB or 30–40% RHB is a more favorable growth media for obtaining high-quality R. delavayi seedlings, while achieving sustainable horticulture production.

Studies on the Production of Protease by Aspergillus Oryzae Ncim 637 under Solid-state Fermentation using Mixed Substrates of Prawn’s Shell and Fish Meal Powder

Proteases are the enzymes that catalyze the breakdown of protein molecules into peptides and amino acids. Because of the vast variety of applications of the proteases in the current investigation. the production of protease from Aspergillus oryzae NCIM 637 was carried out under solid-state fermentation. The highest yield of the enzyme was screened using two substrate powders (Prawn's shell and fish meal powder), and it was observed that combined substrate powder has a higher potential to serve as a substrate for neutral protease synthesis by the fungal strain Aspergillus oryzae NCIM 637. Fermentation time (5 days), fermentation temperature (35°C), optimum pH (7), initial moisture content (46.40%), inoculum age (4 days), and inoculum volume were all optimized (1.0ml). The influence of additives such as carbon source maltose (2%) and nitrogen source casein (2%) was investigated, with a maximum production of 562.57U/gds. When the enzyme was partially purified using ammonium sulfate precipitation, the activity of the protease enzyme was found to be 570U/gds. Proteases have a wide range of applications in the food, pharmaceutical, and leather industries, as well as brewing.