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Aims:The present study was carried out to design a phosphate solubilizing bacterial (PSB)-based biofertilizer using locally produced fruit waste. Method and results:Two PSB strains Pseudomonas aeruginosa CMG4 and AAC1 were inoculated into compost. Six compost piles were prepared with carbon:nitrogen (C:N) ratio 30:1. Four piles were inoculated with PSB and two piles served as a control. After 125 days, composts were considered mature at 29-31°C in the pH range of 7.1-7.3 and 32%-35% moisture content (MC). Accessible calcium (Ca) content increased up to 50 g kg −1 . Microbial analysis showed the survival of P. aeruginosa species in the maturing compost even at higher temperature (~53°C). Native bacterial load was retrieved in the range of 10 9 -10 11 CFUg −1 . Heavy metal concentrations including copper (Cu), lead (Pb), chromium (Cr) and cadmium (Cd) were found to occur below critical thresholds. Seed germination index for compost toxicity was found to be >80%, significantly higher than animal manure and chemical fertilizer, that is, 78% and 31%, respectively, suggesting non-toxicity. Conclusions:The evaluation of prepared compost by physicochemical parameters revealed that inoculation of P. aeruginosa does not affect the temperature, MC, carbon to nitrogen ratio, organic matter and Mg content but significantly increased the accessible Ca content, suggesting the solubilization of inorganic Ca bound phosphate. Compost was safe in terms of heavy metal concentration and seed germination. Significance and impact of study:This study encourages that the PSB-rich tailored compost can be utilized as a phosphatic biofertilizer to fulfil the demand for phosphorus which would improve and sustain soil fertility.

A comprehensive profile of structural and functional dynamics of fungal community during fruit waste composting was investigated. For this purpose, fruit waste was composted in a windrow setup. Representative samples were collected at varied range of incubation temperatures during composting period and employed to physicochemical and microbiological culture dependent and independent analysis. Time-series data revealed that variation in fungal load is temperature dependent that influenced morphotypes’ shifts during different stages of composting. Shifts in abiotic factors, availability of accessible nutrients, water loss, pH and electrical conductivity participated in the transition of community and compost maturity. Culture-based analysis showed rich microbial compost community, dominant with Aspergillus, Mucor, Rhizopus and Penicillium. Denaturing gradient gel electrophoresis analyses demonstrated the prevalence of diverse community in compost with detectable bands corresponding to Penicillium at mesophilic temperature while undetectable bands corresponding for Aspergillus. Succession in microbial community was observed during composting as with temperature variations. Illumina Miseq revealed fungal diversity including Mortierella sp from phylum Zygomycota as the most dominant fungi and Coprinopsis sp as second dominant from Basidiomycota, mainly associated with lignocellulosic degradation. Moreover, Aspergillus fumigatus (ADIF1) was found as the most promising cellulase and pectinase producers at higher temperature showing its potential for efficient environmental management utilization. Current findings suggest that transformation of fruit waste into seed germination friendly compost that can be used as an efficient organic fertilizer and incorporation of sensitive molecular technique suggests the transition of microbial community and improvement in microbial diversity.

A comprehensive pro le of structural and functional dynamics of fungal community during fruit waste composting was investigated. For this purpose, fruit waste was composted in a windrow setup. Representative samples were collected at varied range of incubation temperatures during composting period and employed to physicochemical and microbiological culture dependent and independent analysis. Time-series data revealed that variation in fungal load is temperature dependent that in uenced morphotypes' shifts during different stages of composting. Shifts in abiotic factors, availability of accessible nutrients, water loss, pH and electrical conductivity participated in the transition of community and compost maturity. Culture-based analysis showed rich microbial compost community, dominant with Aspergillus, Mucor, Rhizopus and Penicillium. Denaturing gradient gel electrophoresis analyses demonstrated the prevalence of diverse community in compost with detectable bands corresponding to Penicillium at mesophilic temperature while undetectable bands corresponding for Aspergillus. Succession in microbial community was observed during composting as with temperature variations. Illumina Miseq revealed fungal diversity including Mortierella sp from phylum Zygomycota as the most dominant fungi and Coprinopsis sp as second dominant from Basidiomycota, mainly associated with lignocellulosic degradation. Moreover, Aspergillus fumigatus (ADIF1) was found as the most promising cellulase and pectinase producers at higher temperature showing its potential for e cient environmental management utilization. Current ndings suggest that transformation of fruit waste into seed germination friendly compost that can be used as an e cient organic fertilizer and incorporation of sensitive molecular technique suggests the transition of microbial community and improvement in microbial diversity. Statement Of NoveltyEven though numerous studies have looked at the signi cance of microbial communities in composting, there is still potential for more research into microbial populations due to their variability based on feedstock and environmental conditions. Therefore, this study is envisaged to determine the fungal diversity of organic compost using local indigenous waste via standard plate count, DGGE and next generation sequencing. It was observed that using a culture-based approach alone is insu cient, and that combining it with sequencing uncovered an uncultured fungal population that is catabolically diverse and plays a prominent role in producing germination friendly compost. We believe that the manuscript ndings will provide valuable insights into the microbial-driven composting of fruit waste, that can aid in rapid co-composting of lignocellulosic waste.