Honey exhibited potential antimicrobial activity against multidrug resistant (MDR) bacteria that continues to be a serious health problem. We reported the in-vitro activity of Saudi Sumra honey against clinical pathogenic bacteria and fungi, antibiofilm, anti-quorum-sensing (QS) and antioxidant activities in relation to its phytochemical composition assessed by gas chromatography-mass spectrometry (GC-MS). Broth dilution method and scavenging activities against 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and β-carotene bleaching assays were performed. The GC-MS analysis of Sumra honey showed that 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one 1-methylcyclopropanemethanol were the major identified phytoconstituents. Sumra honey showed a minimum inhibitory concentration (MIC) to clinical isolates of Staphylococcus aureus including methicillin-resistant Staphylococcus aureus (MRSA) at 300 mg/mL, Pseudomonas aeruginosa (250 mg/mL), Escherichia coli (350 mg/mL) and Acinetobacter baumannii (250 mg/mL); clinical fungal isolates—Candida auris (600 mg/mL) and Cryptococcus neoformans (>1000 mg/mL); wild type fungal isolates—Candida krusei (>1000 mg/mL) and Candida albicans (700 mg/mL). In addition, Sumra honey demonstrated promising inhibition targeting biofilm formation by 59% for Bacillus subtilis, 48% for S. aureus, 38% for E. coli, and 33.63% for P. aeruginosa. The violacein production in Chromobacterium violaceum was reduced to 68%, whereas pyocyanin production in P. aeruginosa was reduced to 54.86% at ½ MIC. Furthermore, Sumra honey exhibited strong antioxidant activities (DPPH − IC50 = 7.7 mg/mL; ABTS − IC50 = 5.4 mg/mL; β-carotene − IC50 = >20 mg/mL). Overall, obtained data highlighted the promising potential therapeutic use of Sumra honey treating infections caused by MDR bacteria and fungi. Moreover, Sumra honey can be a good candidate as an inhibitor agent for bacterial cellular communication in strains of P. aeruginosa and C. violaceum.

In this study fungal profiles of agricultural field soil irrigated with industrial wastewater and sewage containing varying concentrations of heavy metals (Chromium, Nickel, Cobalt, Copper and Cadmium) have been investigated. The impact of long term heavy metal contamination on emergence of heavy metal tolerant soil fungal population, changes in morphological diversity and metal tolerance limits among isolated fungi was studied. The agricultural field soil received long term (>20 years) wastewater application showed metal accumulation compared to the untreated soil. The viable count of soil fungal population from three different agricultural field soil was found in order of 10 5 to 10 4 CFU gm -1 of soil indicating a normal viable count with little variations. Viable plate count of fungal population on metal amended plates decreased with increasing concentration of tested metals (Cr 6+ , Cd ++ . Cu ++ , Co ++ and Ni ++ ) from 100 to 400 µgml -1 . The decrease was higher on cadmium amended plates and lower against Chromium. The control site, which did not receive wastewater application showed relatively less metal tolerant fungal viable count on Cd ++ and Ni ++ plates when compared at 100 µgml -1 as compared to contaminated sites. Similarly, presence of metal tolerant fungal population was also observed from wastewater sample. The common soil fungi isolated and characterized from metal amended plates belong to 18 genera and 15 unidentified species. Occurrence of different fungal genera from site A B and C indicated different patterns of decrease on different metal amended plates with increasing concentration. Among these 73 isolated fungal species a high level of tolerance was recorded to Cr 6+ followed by Cu ++ , Co ++ and Ni ++ while the lowest level of tolerance was for Cd ++ . The minimum inhibitory concentration (MIC) values of 73 metal tolerant fungal isolates, was ranged from 200 to 2000 μgml -1 against one or more heavy metals. The level of tolerance to heavy metals also varied even among the isolates of single genus. Aspergillus was the predominant genus recovered from contaminated soils where the MIC values are highly varied among different isolates of Aspergillus. The current study found that long term release of wastewater has not disturbed the fungal population dynamics in contaminated sites as compared to uncontaminated sites. However, it tends to exert selective pressure on fungal populations of soil, leading to the development of increased level of metal tolerance in fungal species.

Purpose Rhizospheric soil fungi are critical for plant and soil health. However, their multiple functional traits and impact on plant growth have not been systematically explored. Methods During this study, biochemical traits of 73 indigenous soil fungal isolates and 15 unidentified isolates related to plant growth promotion and production of extracellular enzymes were studied. Results Forty four (65.67%) of the total isolates produced indole acetic acid (IAA) followed by siderophore (52.23%), phosphate solubilization (37.31%), and antibiotic (11.93%). 91.04% of the studied isolates produced ammonia whereas 28.35% produced organic acid. Extracellular enzyme activities of lipase, amylase, chitinase, and cellulase were detected among 95.52%, 61.11%, 35.82%, and 41.79% isolates, respectively. Based on these activities, 73 fungal isolates were categorized into different biotypes. Quantitative analysis of IAA production and phosphate solubilization was carried out for Aspergillus, Penicillium, and Rhizopus isolates. Aspergillus isolates exhibited varying activities of IAA production and phosphate solubilization. Most of the Aspergillus isolates and some other fungi demonstrated multiple activities. Based on the multiple traits of selected fungal isolates, Aspergillus sp-07, Penicillium sp-03, and Rhizopus sp-02 were further evaluated in different combinations for their inoculation effect on the growth and yield of wheat under field conditions. Conclusions The results indicated that these isolates could be developed into bio-inoculants to enhance plant growth. The consortium of these three isolates was also found to be compatible and beneficial for plant growth.

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Products from microalgae have multiple commercial applications including for nutrition, health and fuel uses, but the breakage and release of products from biomass remains a challenge, particularly for microalgal strains with thick cell walls. Fungal strains were isolated due to their ability to degrade microalgal biomass of Parachlorella hussii, Hindakia tetrachotoma and Jaagichlorella luteoviridis that was buried in soil at 25°C for 8 weeks. Fungal isolates were identified by sequencing, with the three most ubiquitous strains identified as Fusarium solani, Doratomyces nanus and Actinomucor elegans.Crude enzyme extracts from these strains were used to quantify the saccharification of intact or lipid-extracted Chlorella vulgaris biomass. The D. nanus extract gave the highest saccharification efficiency of 57% from the intact biomass and 76% from the lipid-extracted biomass, without need for any pre-treatment. Outcomes of this study can improve the design of microbial enzymes to efficiently degrade microalgal biomass for various industrial applications.