Inoculum Rate Research Articles

Optimization of Lignocellulosic Enzyme production by Microbial Strains: Study of Kinetics and Environmental Influences

In the context of valorizing lignocellulosic biomass for biofuel production a mixture of forest residues (FW) and aromatic-medicinal plant wastes (AMPW) was considered in this study to assess its ability to support the production of cellulolytic enzymes by Aspergillus niger, Trichoderma longibrachiatum and Zymomonas mobilis. The residue mixture promoted growth and cellulase production by the microbial strains after 6 days of incubation. Enzymatic activity was determined using filter paper activity (FPase) and endoglucanase carboxymethylcellulase (CMase) assays. Optimization of enzymatic activity was investigated at pH levels (2, 4, 6, 8), various temperatures (22°C, 30°C, 37°C, 45°C) and different inoculum rates (1.5 × 107, 2 × 107 and 2.5 × 107 spores per gram of substrate). Maximum enzymatic activity was observed in Aspergillus niger with FPase and CMCase yields of 23.12 ± 0.1 and 29.78 ± 0.15 U/gds respectively. The highest enzymatic activity was recorded at temperatures of 30°C and 37°C, pH levels of 4 and 6 and with an inoculum rate of 2.5 × 107. The selection of the strain and the optimization of operational conditions are crucial for efficient enzymatic production in the context of biorefinery.

Biocontrol of Aflatoxin-Producing Aspergillus flavus ATCC 22546 by a Non-Aflatoxigenic Aspergillus flavus ATCC 9643

The biological control of Aspergillus flavus and A. parasiticus by non-aflatoxigenic strains has been introduced in cotton- and peanut-cultivating fields and proven successful at reducing aflatoxin (AFB) contamination of crops and agricultural soils. In this study, a non-aflatoxigenic strain, A. flavus ATCC 9643 (ATCC 9643), was evaluated for its ability to competitively inhibit the growth of an aflatoxigenic strain, A. flavus ATCC 22546 (ATCC 22546), and mitigate AFB production in ATCC 22546 during competitive growth. To comparatively analyze the suppressive effect of ATCC 9643 on ATCC 22546, a non-aflatoxigenic strain (A. flavus ATCC 96045, known as AF36) was used as a positive control in some experiments. The two non-aflatoxigenic strains did not produce AFB1 or AFB2 owing to the absence of several AFB biosynthesis-related genes, especially aflK and aflL, which encode versicolorin B synthase and desaturase, respectively. To create a competitive growth environment, ATCC 9643 and ATCC 22546 were co-inoculated into a solid agar medium, and they grew at similar rates when added at a 1:1 ratio. Increasing the inoculum rate of ATCC 9643 (1:1, 1:3, 1:5) dramatically inhibited ATCC 22546 growth, and AFB production was effectively decreased by about 84%, 95%, and 97% by treatment with ATCC 9643. On rice, ATCC 22546 attenuated ATCC 9643 growth only when the rice was submerged in distilled water, whereas agar addition enhanced it. Taken together, ATCC 9643 is a promising candidate biological agent for suppressing aflatoxigenic A. flavus strain growth and alleviating AFB contamination. Further studies on AFB reduction in crop fields, including cotton-cultivation and maize-cultivation fields, are warranted.

Co‐inoculation of Azospirillum brasilense and late nitrogen fertilization for no‐till soybean production

AbstractSoybean [Glycine max (L.) Merr.] is highly efficient in the biological N2 fixation (BNF) process through the association of bacteria of the genus Bradyrhizobium in the root nodules of the plants. However, there are still doubts about the need to complement soybean N demand through N fertilization in high‐yield environments. In addition, the real impact of co‐inoculation of soybean with Azospirillum brasilense and Bradyrhizobium spp. is not yet clear in such environments. A field experiment was conducted from 2012 to 2021 with six soybean cropping seasons in a crop rotation scheme with black oat (Avena strigosa Schreb), maize (Zea mays L.), and wheat (Triticum aestivum L.) under no‐till (NT) in Southern Brazil. Soybean seeds were co‐inoculated with A. brasilense (strains Ab‐V5 and Ab‐V6) shortly after inoculation with Bradyrhizobium japonicum, and different levels of N fertilization were used in top dressing at the start of pod formation (R3). Soybean nutritional status and grain yield were not benefited by co‐inoculation with A. brasilense. Since the increased inoculum rate of A. brasilense co‐inoculated with rhizobia in soybean compromised both N nutrition and grain yield, this practice should not be encouraged. There was no need to complement soybean N demand through N fertilization during the reproductive stage. Soybean achieved grain yields of 5.0–5.7 Mg ha−1 and, even so, there was no need to complement N demand through N fertilization. The results suggest that soybean N demand in a high‐yielding environment under NT could be satisfied exclusively through the optimization of BNF.

An optimization approach on the determination of volatile composition, bioactive compounds and sensory properties of Lben: Effect of fermentation conditions, starter system and substrate composition

In order to optimize the quality of Lben, a Moroccan fermented milk, the impact of starter, fermentation conditions and substrate composition on its organoleptic and technological characteristics was studied using response surface methodology. Using autochthonous bacterial strains (three strains of Lactococcus lactis subsp. lactis and one Leuconostoc mesenteroides subsp. mesenteroides), the effect of independent factors including temperature (25–35 °C), inoculum rate (0.4–1.2%) and milk fat concentration (0.1–3.0%) on the acidifying performance, texture, proteolysis, sensory properties, some aroma-active compounds including butanoic acid, ethanol, acetoin, acetaldehyde and diacetyl, and biological activities (ACE-i and GABA) was evaluated. According to central composite design, an optimized model for Lben production was developed based on fermentation time, Lben sensory quality and its biological activities, including ACE-i activity and γ-aminobutyric acid content. The optimal condition was obtained with 863.86 min fermentation time, 0.97% fat level, 1.2% inoculum rate corresponding to 8.08 log10 cfu/mL at 26.75 °C fermentation temperature.

Molecular binding mechanism and novel antidiabetic and anti-hypertensive bioactive peptides from fermented camel milk with anti-inflammatory activity in raw macrophages cell lines.

The investigation was to determine the effect of camel milk fermented with Limosilactobacillus fermentum KGL4 (MTCC 25515) on ACE-inhibiting, anti-inflammatory, and diabetes-preventing properties and also to release the novel peptides with antidiabetic and anti-hypertensive attributes with molecular interaction studies. Growth conditions were optimised on the basis of total peptide production by inoculating the culture in camel milk at different rates (1.5, 2.0, and 2.5%) along with different incubation periods (12, 24, 36, and 48h). However, after 48h of fermentation with a 2.5% rate of inoculum, the highest proteolytic activity was obtained. Reverse phase high-pressure liquid chromatography (RP-HPLC) was used to calculate the % Rpa from permeates of 3kDa and 10kDa fractions. Molecular weight distributions of fermented and unfermented camel milk protein fractions were compared using SDS-PAGE. Spots obtained from 2D gel electrophoresis were separated on the basis of pH and molecular weight. Spots obtained from 2D gel were digested with trypsin, and the digested samples were subjected to RP-LC/MS for the generation of peptide sequences. The inhibition of tumour necrosis factor alpha, interleukin-6, and interleukin-1 during fermentation was studied using RAW 264.7 macrophages. In the study, fermented camel milk with KGL4 (CMKGL4) inhibited LPS-induced nitric oxide (NO) production and pro-inflammatory cytokine production (TNF-α, IL-6, and IL-1β) by the murine macrophages. The results showed that the peptide structures (YLEELHRLNK and YLQELYPHSSLKVRPILK) exhibited considerable binding affinity against hPAM and hMGA during molecular interaction studies.

Chemical and Biological Control of Wet Bubble Disease (Hypomyces perniciosus) in Mushroom Crops

Wet bubble disease (WBD) is globally becoming a major problem in mushroom crops. The effectiveness of the application of different chemical (chlorothalonil, metrafenone and prochloraz-Mn) and Bacillus (B. subtilis and B. amyloliquefaciens strains) -based products for the control of WBD in artificially inoculated mushroom crops was studied. Six trials were carried out, with three different inoculum rates. The effect of fungicides on mushroom productivity and disease incidence was assessed. The effectiveness of the treatments is statistically related to the harshness of the disease. The greatest reductions in disease incidence were achieved after treatments with chemical fungicides, notably prochloraz-Mn. When the outbreak was strong, the low calculated incidence reduction values for metrafenone treatments advised against their application. The results also indicated the low effect of both bio-fungicides, at the doses and timing evaluated, for the control of this mushroom disease.

Increased bulb yield following seed coating of radish (Raphanus sativus L.) with selected isolates of Trichoderma species in Rhizoctonia solani infected soil

Abstract: Red radish (Raphanus sativus) is highly susceptible to the soil-borne fungus Rhizoctonia solani, which can cause severe crop losses. In a glasshouse experiment, untreated seeds of radish cvs. French Breakfast and Red Round were grown in potting mix where R. solani inoculated wheat-bran was added at rates of 0.25, 0.5 and 1.0 g per 100 g potting mix. Seedling emergence was reduced by one third and two thirds respectively by the two higher inoculum rates, and final plant numbers were ca. 20%, 50% and 80% less than in the uninoculated control. The ability of Trichoderma spp. to increase radish yields by limiting the damage caused by R. solani has long been known but has not been evaluated in New Zealand. Inoculum of each of four Trichoderma spp. isolates LU132 (T. atroviride), LU785 (T. hamatum), LU1437 (T. harzianum) and LU1358 (T. polysporum) was prepared in sterile wheat-bran and 0.5 g wheat-bran was added per 100 g potting mix. In a second glasshouse experiment, R. solani (0.25 g inoculated wheat-bran) was added per 100 g potting mix before untreated seeds of both radish cultivars were sown. Potting mix without either R. solani or Trichoderma served as the control. Maximum seedling emergence did not differ among the treatments for cv. French Breakfast, but was increased by the presence of either isolate LU132 (T. atroviride) or LU1358 (T. polysporum) for cv. Red Round. The presence of isolate LU1347 (T. harzianum) in the potting mix significantly increased plant survival in both cultivars. Each of the four Trichoderma isolates reduced the percentage of diseased plants with isolate LU132 (T. atroviride) providing the strongest response. In a third glasshouse experiment, Trichoderma treated seeds, thiram fungicide treated and untreated seeds of both radish cultivars were sown in naturally R. solani infected soil. The same treatments were used in a field trial at a site known to be infected by R. solani. In the third glasshouse experiment, seed treatment with Trichoderma isolates LU1347 (T. harzianum), LU1358 (T. polysporum) and LU785 (T. hamatum) significantly increased bulb fresh weight in cv. Red Round, but no treatments increased bulb fresh weight in cv. French Breakfast. In the field experiment, bulb yield for the thiram seed treatment did not differ from that of the untreated control. However, seed treatment with isolate LU785 (T. hamatum) increased subsequent bulb yield by 96% for both cultivars, and seed treatment with isolate LU132 (T. atroviride) or isolate LU1358 (T. polysporum) also significantly increased bulb yield (by 85% and 60% respectively) in cv. French Breakfast. A possible explanation for this result was sought by undertaking a fourth glasshouse experiment for radish cv. Red Round only. In this experiment, all four Trichoderma spp. isolates more than doubled bulb yield by producing not only a greater number of bulbs but also larger bulbs than the untreated control. Trichoderma seed coating may provide an alternative to fungicide seed treatment for radish production.

Sustainability of food side streams: a case study of fermented blends made with sour whey and sunflower press cake powder using the back-slopping technique

The exploitation of by-products is a key factor to increase the sustainability of the agri-food chain and fermentation is a simple and eco-friendly process for achieving safe and suitable food materials. In this study, we investigated the possibility to manage a spontaneous fermentation of blends made with different proportions of two food side streams (bovine acid whey and sunflower press cake powder) through the application of a back-slopping technique of the mixed material incubated at 26°C in static conditions. A full-factorial 2-factor 3-level design of experiment was applied to infer the effect of the percent (w/w) of press cake powder in the mixture (20, 25, and 30%) and the rate of back-slopping inoculum (15, 30, and 45%). The pH value, titratable acidity, content of sugars, organic acids, and phenolic acids, enumeration of lactic acid bacteria, yeasts and molds, bacterial contaminants, presumptive Bacillus cereus, and Escherichia coli were measured for each fermentation step at 0, 24, 48, and 72 h. On the same samples, a metataxonomics analysis, targeted on bacterial 16S rRNA gene and fungal ITS region, was performed by using the Illumina MiSeq platform. Acidification of the blends (on average, starting pH = 5.45 ± 011, final pH = 4.61 ± 0.11; starting acidity =13.68 ± 1.02 °SH/50 mL, final acidity = 28.17 ± 2.92°SH/50 mL) and high LAB counts (on average, 9.39 log CFU/g ± 0.25) were observed at the end of each refreshment. In all fermented mixtures, B. cereus, E. coli, and molds counts were lower than the detection limit (<2 log CFU/g), whereas bacterial contaminants, overall spore-formers, were always present (3.74 log CFU/g ± 0.27). After 72 h, the dropping of pH value was maximum, yielding significant differences compared to previous fermentation steps (p < 0.01); particularly, the lowest pH (4.45 ± 0.06) was achieved in the central points of DoE (25% of press cake powder and 30% of back-slopping rate), representing the most suitable condition. Results from both culture-dependent and -independent techniques were consistent; although Lactococcus lactis, continuously deriving from the acid whey, was the main LAB, Pediococcus pentosaceus appeared and, in some cases, became the dominant species. Finally, a long-term trial (about 1 month), using the best condition previously pointed out, was performed with an extension of the incubation time to 84 h for each refreshment. The increase in acidity forced the natural selection toward acid-tolerant microbial strains confirming the former results. Although preliminary, these findings can be useful for developing innovative operations to manage these two relevant side streams implementing the circularity of food resources.

Efektivitas Inokulum Tunggal dan Konsorsium Fungi Mikoriza Arbuskula pada Pembibitan Tanaman Indigofera zollingeriana

Arbuscular mycorrhizal fungi (AMF) are potential biofertilizers for plants. The succeed and quality of AMF inoculation is related to the type of AMF and plants. This study aimed to find the most effective AMF species in Indigofera zollingeriana nurseries. This experiment study was designed using a completely randomized design with six treatments and five replications based on different types of AMF in single and consortium forms. Treatment details include: IFMIX (consortium: a mixture of five types of AMF), IFTE (Glomus etinucatum), IFTM (Glomus manihotis), IFTA (Acaulospora tuberculata), IFTG (Gigaspora margarita), IFTS Glomus sp. Data were analyzed using Analysis of Variance (ANOVA) and Duncan's Multiple Range Test. Based on the results of variance, AMF inoculation at Indigofera zollingeriana nurseries in a single form (IFTE, IFTM, IFTA, IFTG, and IFTS) resulted in effectiveness that was not significantly different with the consortium FMA inoculation (IFMIX) against AMF colonization, plant height, stem diameter, fresh and dry biomass of plants. Inoculation of inoculums in a single IFTE form resulted in a higher colonization value (p<0.05) than single inoculums IFTA and IFTM. It can be concluded that inoculation of a single AMF (Glomus etinucatum, Glomus manihotis, Acaulospora tuberculata, Gigaspora margarita, Glomus sp.) against AMF consortium produced the same symbiotic effectiveness on root colonization, morphological response and plant biomass production level in Indigofera zollingeriana nurseries. The root colonization rate of a single IFTE inoculum was better than a single inoculum of IFTA and IFTM.

7α and 7β Hydroxylation of Dehydroepiandrosterone by Gibberella sp. and Absidia Coerulea Biotransformation

The hydroxylation of dehydroepiandrosterone (DHEA) to 7α -hydroxy-5-androstene-17-one (7α-OH-DHEA) and 7β-hydroxy-5-androstene-17-one (7β-OH-DHEA) by Gibberella sp. CICC 2498 and Absidia coerulea CICC 41050 was investigated. The media ingredients were optimized. Single factors such as the DHEA concentration, culture time, medium volume, and inoculum rate were individually investigated to generate optimum biotransformation conditions. An orthogonal optimization process using a four-factor, three- level L9 (33) experiment was designed and performed. Finally, the maximum production of 7β-OH-DHEA from DHEA biotransformation by Absidia coerulea is 69.61%. This strategy would provide a possible way to enhance the 7β-OH-DHEA yield in the pharmaceutical industry.

Effect of Rhizobium inoculum on the Growth, Yield and Quality of Soybean

Rhizobium inoculation can increase soybean yield, but its performance is influenced by soybean genotypes. The objective of the study was to assess the effect of Rhizobium inoculum on the growth, yield and quality of soybean varieties. In this regard, five different rates of Rhizobium inoculum were applied on eight distinct soybean varieties namely Shohag, BARI Soybean-5, BARI Soybean-6, PB-1, Binasoybean-1, Binasoybean-2, Binasoybean-3 and Binasoybean-4. The experiment was set up using a randomized complete block design with three replications. Soybean varieties showed variability in terms of plant stature, number of branches plant-1 and number of nodules plant-1 at different days after sowing. Among the varieties, Binasoybean-4 produced the tallest plant at 45 and 60 DAS and at 60 DAS variety PB-1 produced the tallest plant. At 45 DAS Binasoybean-2, at 60 DAS BARI Soybean-6 and at 75 DAS Binasoybean-4 produced the highest number of branches plant-1. In case of nodule production, Binasoybean-3 produced the highest number of nodules palnt-1 at 45, 60 and 75 DAS. Inoculation of seeds with 100% of RD of Rhizobium gave maximum plant height, number of branches plant-1 and nodules plant-1. It is noticed that Binasoybean-4 with the application of 100% of RD of Rhizobium inoculum produced the tallest plant and number of branches plant-1 at 45 DAS but at 60 DAS, though the tallest plant was found in the variety Binasoybean-4 with 100% of RD of Rhizobium inoculum but it was statistically identical to Binasoybean-3 with 100% of RD of Rhizobium inoculum. Binasoybean-4 with 100% of RD of Rhizobium inoculum also gave maximum number of branches plant-1 at 75 DAS. But Binasoybena-3 with 100% of RD of Rhizobium inoculum produced the highest number of nodules plant-1 at 60 DAS. In case of variety Binasoybean-1 performed superiorly in terms of all the yield and yield contributing characters. Application of 100% of RD of Rhizobium inoculum also showed superior performance. The highest seed yield (2.92 t ha-1) was recorded in Binasoybean-3 with the application of 100% of RD Rhizobium inoculum. The highest protein content was also documented in this treatment combination. Finally, it may conclude that Binasoybean-3 with the application of 100% of RD Rhizobium inoculum might be recommended for maximizing seed yield and to get best quality soybean.

Exploring the potential of Lacticaseibacillus paracasei M11 on antidiabetic, anti-inflammatory, and ACE inhibitory effects of fermented dromedary camel milk (Camelus dromedaries) and the release of antidiabetic and anti-hypertensive peptides.

The goal of this investigation was to find antidiabetic peptides and inhibit angiotensin converting enzyme (ACE) in Lacticaseibacillus paracasei (M11) fermented dromedary camel milk (Camelus dromedaries). According to the findings, the rate of antidiabetic activity increased along with the incubation periods and reached its peak after 48 hr of fermentation. The inhibitions of α-amylase, α-glucosidase, and lipase were 80.75, 59.62, and 65.46%, respectively. The inhibitory activity of ACE was 78.33%, and the proteolytic activity was 8.90 mg/mL. M11 at 0.25 mg/mL effectively suppressed LPS-induced pro-inflammatory cytokines and their mediators such as NO, TNF-α, IL-6, and IL-1β in RAW 264.7 cells. The rate of inoculum in the optimization phase was 1.5-2.5%, and the greatest proteolytic activity was observed after 48 hr of fermentation. The investigation of the above property in the ultrafiltered fermented milk exhibited the highest antidiabetic and ACE inhibition activities in the 3kDa than 10kDa fractions. The molecular weight was determined employing SDS-PAGE, and the six-peptide sequences were identified using 2D gel electrophoresis. Due to its high proteolytic activity, the L. paracasei strain has been reported to be useful in the production of ACE-inhibitory and antidiabetic peptides. Amino acid sequences such from ɑ1, ɑ2, and β-caseins have been identified within fermented camel milk by searching on online databases, including BIOPEP (for antidiabetic peptides) and AHTPDB (for hypertension peptides) to validate the antidiabetic and ACE-inhibitory actions of several peptides. PRACTICAL APPLICATIONS: The study aims to identify antidiabetic peptides and inhibit ACE in dromedary camel milk fermented with Lacticaseibacillus paracasei M11. Maximum antidiabetic and ACE-inhibitory actions of the fermented camel milk were observed in 3kDa permeate fractions. Fermented camel milk significantly reduced the excessive TNF-α, IL-6, and IL-1β production in LPS-activated RAW 264.7 cells. RP-LC/MS was used to identify 6 bioactive peptides from dromedary fermented camel milk. This fermented camel milk could be used for the management of hypertension and diabetic related problems.

Two-Phase Medium – A New Approach to Microbiological Culturing

We tested a new two-phase culture medium for culturing microorganisms, in particular algae and fungi. In media composed of mixed gel and solid phases of granite, basalt, sandstone, limestone and sodium glass, we observed the growth of selected species inhabiting the boundaries of the gel medium with the solid phase. The species used were Klebsormidium dissectum (F.Gay) H.Ettl & Gärtner, Vischeria polyphem (Pitschmann) Kryvenda, Rybalka, Wolf & Friedl and Muriella decolor Vischer (algae); and Aspergillus tubingensis R.Mosseray, Aureobasidium pullulans (de Bary) G.Arnaud, Chaetomium globosum Kunze and Penicillium sp. Link (fungi). In the six-weeks period of parallel cultures, the growth rate of the algae inoculum in two-phase media was twice that observed in the control culture (gel medium). The algae also maintained high viability in the new medium.

Optimal Liquid Inoculum Conditions and Grain Medium Enhanced Hispidin Production by Species of Genus Phellinus (Agaricomycetes) in Solid-State Fermentation.

This study aimed 1) to screen a high hispidin production strain from 12 strains of genus Phellinus and 2) to evaluate the effects of liquid inoculum conditions and grain medium on this strain's hispidin production levels after solid-state fermentation. The results showed that Ph. linteus 04 led to the highest hispidin production; this strain was then selected to elucidate the optimal liquid inoculum conditions and grain medium for hispidin production. Various liquid inoculum conditions were evaluated, and the highest hispidin yield, specific productivity of hispidin, and total content of hispidin were found to be optimal at 1 week of liquid inoculum culture time, cultured with potato dextrose broth, and using a 10% inoculum rate, with each condition resulting in 0.350, 0.325, and 0.328 mg/g dry weight of mycelium, 0.352, 0.251, and 0.249 μg/mg of specific productivity per week, and 57.90, 60.23, and 61.77 mg/kg dry weight of brown rice medium, respectively. These liquid inoculum conditions were then used to determine the appropriate grain medium for hispidin production. The highest hispidin yield and total content of hispidin were observed in pearl barley (1.107 mg/g dry weight of mycelium and 199.76 mg/kg dry weight of pearl barley), which led to results that were 4.73-fold and 5.35-fold higher than those of the control (brown rice medium). Overall, this study shows that Ph. linteus hispidin production can be enhanced by solid-state fermentation using optimal liquid inoculum conditions and the appropriate grain medium.

Biocontrol of Aflatoxins Using Non-Aflatoxigenic Aspergillus flavus: A Literature Review.

Aflatoxins (AFs) are mycotoxins, predominantly produced by Aspergillus flavus, A. parasiticus, A. nomius, and A. pseudotamarii. AFs are carcinogenic compounds causing liver cancer in humans and animals. Physical and biological factors significantly affect AF production during the pre-and post-harvest time. Several methodologies have been developed to control AF contamination, yet; they are usually expensive and unfriendly to the environment. Consequently, interest in using biocontrol agents has increased, as they are convenient, advanced, and friendly to the environment. Using non-aflatoxigenic strains of A. flavus (AF−) as biocontrol agents is the most promising method to control AFs’ contamination in cereal crops. AF− strains cannot produce AFs due to the absence of polyketide synthase genes or genetic mutation. AF− strains competitively exclude the AF+ strains in the field, giving an extra advantage to the stored grains. Several microbiological, molecular, and field-based approaches have been used to select a suitable biocontrol agent. The effectiveness of biocontrol agents in controlling AF contamination could reach up to 99.3%. Optimal inoculum rate and a perfect time of application are critical factors influencing the efficacy of biocontrol agents.

A Greenhouse Method to Evaluate Sunflower Quantitative Resistance to Basal Stalk Rot Caused by Sclerotinia sclerotiorum

Resistance of sunflower to basal stalk rot (BSR) caused by the fungus Sclerotinia sclerotiorum is quantitative, controlled by multiple genes contributing small effects. Consequently, artificial inoculation procedures allowing sufficient throughput and resolution of resistance are needed to identify highly resistant sunflower germplasm resources and to map loci contributing to resistance. The objective of this study was to develop a greenhouse-based method for evaluating sunflower quantitative resistance to BSR that would be simple, space- and time-efficient, high throughput, high resolution, and correlated with field observations. Experiments were conducted with 5-week-old sunflower plants and Sclerotinia-infested millet seed as inoculum to assess the impact of pot size and temperature and to determine the most favorable inoculum rate and placement. Subsequently, an additional experiment was performed to assess the correlation of the greenhouse inoculation procedure with field results by using a panel of 32 sunflower genotypes with known field response to BSR previously determined in multiyear, multilocation artificially inoculated trials. Experimental observations indicated that the newly developed greenhouse inoculation procedure provided improved resolution to identify highly resistant genotypes and was strongly correlated with field observations. This method will be useful for screening of sunflower experimental and breeding materials, disease phenotyping of genetic mapping populations, and evaluation of resistance to different pathogen isolates.

Bacillus velezensis DP-2 isolated from Douchi and its application in soybean meal fermentation.

Soybean meal (SBM) is the most common protein source used in the poultry and livestock industries. It has high-quality protein, an excellent amino acid (AA) profile, and positive isoflavone properties. However, the antigen proteins in SBM are unsuitable for young animals. The objective of this study was to identify a Bacillus strain that can degrade soybean antigen proteins, and to evaluate the feasibility of its application in SBM fermentation. Bacillus velezensis DP-2 was isolated from Douchi, a fermented Chinese food. It degraded 96.14% and 66.51% of glycinin and β-conglycinin, and increased the trichloroacetic acid-soluble protein (TCAN) content by 5.46 times in the SBM medium. DP-2 could secrete alkaline protease and neutral protease, with productivities of 5.85 and 5.99 U mL-1 . It had broad-spectrum, antibacterial activities against Rhizopus nigricans HR, Fusarium oxysporum ACCC37404, Penicillium digitatum SQ2, Aspergillus flavus C1, Aspergillus niger ACCC30005, Trichoderma viride YZ1, Candida tropicalis CICC1630, and Salmonella sp. ZY. For SBM fermentation, the optimal inoculum rate, temperature, and fermentation time of DP-2 were 2.21 × 107 CFU g-1 , 37 °C, and 48 h, respectively. The fermented soybean meal (FSBM) was cream-colored and glutinous. Its crude protein (CP), soluble protein, and TCA-N content were improved by 13.45%, 12.53%, and 6.37 times, respectively. The glycinin and β-conglycinin content were reduced by 78.00% and 43.07%, respectively, compared with raw SBM. Bacillus velezensis DP-2 has potential as a starter culture for SBM fermentation. © 2020 Society of Chemical Industry.

Statistical optimization of cultural variables for enzymatic degradation of aflatoxin B1 by Panus neostrigosus

The aim of this study is to determine the best aflatoxin B1 degradation conditions which was optimized using a combination of the Plackett-Burman and Box-Behnken methods with Panus neostrigosus culture filtrate. Panus neostrigosus was grown in a modified Kirk Broth medium to determine optimal degradation conditions. As a result, aflatoxin B1 was degraded under varying culture conditions. The Plackett-Burman method was designed after sixteen different experiments with fifteen variables. The three most effective variables (Sucrose, yeast extract, wheat bran) were chosen for the Box-Behnken methodology. The aflatoxin B1 degradation rate was 49% in just 1 h exposure to culture filtrate which was obtained under optimal growth conditions; (g-ml/L) sucrose 10, yeast extract 3, wheat bran 3, soytone 5, KH2PO4 2, MgSO4.7H2O 0.5, CaCl2.H2O 0.1, ammonium tartrate 2, trace element solution 10; 28 °C of incubation temperature, medium pH 5, 7.5% inoculum rate, 125 rpm of agitation speed, and a twelve-day incubation period. The SDS-PAGE studies show that the enzyme responsible for AFB1 degradation has 38 kDa molecular weight and has no laccase or MnP activity. To the best of our knowledge, this is the first report for AFB1 degradation by Panus neostrigosus.

The Effect of Non-Saccharomyces and Saccharomyces Non-Cerevisiae Yeasts on Ethanol and Glycerol Levels in Wine

Non-Saccharomyces and Saccharomyces non-cerevisiae studies have increased in recent years due to an interest in uninoculated fermentations, consumer preferences, wine technology, and the effect of climate change on the chemical composition of grapes, juice, and wine. The use of these yeasts to reduce alcohol levels in wines has garnered the attention of researchers and winemakers alike. This review critically analyses recent studies concerning the impact of non-Saccharomyces and Saccharomyces non-cerevisiae on two important parameters in wine: ethanol and glycerol. The influence they have in sequential, co-fermentations, and solo fermentations on ethanol and glycerol content is examined. This review highlights the need for further studies concerning inoculum rates, aeration techniques (amount and flow rate), and the length of time before Saccharomyces cerevisiae sequential inoculation occurs. Challenges include the application of such sequential inoculations in commercial wineries during harvest time.

Host status and disease threshold of Rhizoctonia solani (Kühn (teleomorph: Thanatephorus cucumeris (Frank) Donk), on Chia (Salvia hispanica L.) and its suitability as a rotational crop to (Nicotana tabucum L.)

The study was done following the continued outbreaks of problematic diseases in the production of tobacco (N. tabucum) in Zimbabwe which amongst the problematic ones are Rhizoctonia solani and Fusarium solani. The experiment was conducted at Marondera University of Agriculture Science and Technology in Zimbabwe, aiming to evaluate the suitability of Chia as a rotational crop to tobacco. Chia is a seed oil producing legume crop which is regarded the most suitable in rotation with tobacco at the moment because of its monetary benefit to the farmer hence will encourage crop rotation. An experiment was set up with two trials in three growing seasons arranged in a complete block design. Fusarium solani five treatments were used one control and four other different rates of inoculum 2.5g,3.5g, 5.5g and 7.5g/10ml of Distilled water and Rhizoctonia solani five treatments were used with a control and four other different inoculations rates inoculated at 0.1g, 0.2g, 0.4g and 0.6g/10ml Distilled water. Data collection was based on the disease severity scale and index of Chia, and also histochemical parameters which were hydrogen peroxide content and malonaldehyde content. There was significant (p < 0.05) differences between the different inoculation rates of all the measured parameters under the distinct diseases. Hence Chia cannot be rotated with tobacco even under low levels of disease threshold within the soil, unless proper and intensive management practices are put in place.