o:4033 Spent Coffee Grounds, Plant Growth Promoting Bacteria, and Medicinal Plant Waste: The Biofertilizing Effect of High-Value Compost en Abstract: Composting of mixed medicinal plant waste was performed with the addition of mixture of plant growth promoting bacteria (PGPB), including Streptomyces sp., Paenybacillus sp., Bacillus sp., and Hymenobacter sp., and portions of spent coffee grounds (SCG). To assess the maturity and quality parameters of the compost, chemical and biological parameters (C/N ratio, loss of organic matter, CO2 production, dehydrogenase activity (DHA), and phytotoxicity) were evaluated during the three months of the composting process. The results revealed that the control sample (without the addition of SCG and PGPB) had evidently lower values of DHA during the entire monitoring period in comparison to other samples, indicating lower microbial activity in the compost mixture. Also, according to the released CO2, the composting process was accelerated in all samples where the SCG and PGPB were added, enabling a reduction in time needed for mixed plant waste to decompose. The germination index (GI) of the tested seeds indicated that the produced compost was acceptable and safe, with regard to all of the evaluated samples. However, at the end of the process the samples contained SCG and PGPB, which caused an increase of more than 50% of the GI in comparison to the control sample, expressing a high phyto-stimulant effect and improving the biofertilization impact. compost; herbs waste; spent coffee grounds; PGPB; germination index; phytotoxicity 1552099 10.3390/su16041632 2024-02-21T07:16:02.791Z 44 no 46 Snežana Dimitrijević Institute of Medicinal Plants Research “Dr Josif Pančić” 46 Marija Milić Faculty of Technology and Metallurgy, University of Belgrade 46 Aneta Buntić Institute of Soil Science 0000-0002-7068-1804 46 Suzana Dimitrijević-Brankovć Faculty of Technology and Metallurgy, University of Belgrade 46 Vladimir Filipović Institute of Medicinal Plants Research “Dr Josif Pančić” 46 Vera Popović Institute of Field and Vegetable Crops, Novi Sad 46 Ivan Salamon Faculty of Humanities and Natural Sciences, University of Presov, Slovakia application/pdf 1482902 https://unilib.phaidrabg.rs/o:4033 no yes 1 70 92000001 71A05 Sustainability 2024