Algal sludge from Taihu Lake can be utilized to create novel PGPR-containing bio-organic fertilizers
Miao Zhang, Rong Li, Liangliang Cao, Juanjuan Shi, Hongjun Liu, Yan Huang, Qirong Shen
Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Jiangsu Key Lab for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, 210095 Nanjing, Jiangsu Province, PR ChinaAbstract.
Large amounts of refloated algal sludge from Taihu Lake result in secondary environmental pollution due to annual refloatation. This study investigated the possibility to produce bio-organic fertilizer (BIO) using algal sludge as a solid-state fermentation (SSF) medium. Results showed that addition of algal sludge contributed to efficient SFF by a plant growth-promoting rhizobacteria (PGPR) strain SQR9 and improved the nutrient contents in the novel BIO. The optimum water content and initial inoculation size were 45% and 5%, respectively. After 6 days of SSF, the biomass of strain SQR9 was increased to a cell density of more than 5 × 107 CFU g−1. Microcystins were rapidly degraded, and a high germination index value was observed. Plant growth experiments showed that the produced BIO efficiently promoted plant growth. Additional testing showed that the novel SSF process was also suitable for other PGPR strains. This study provides a novel way of high-value utilization of algal sludge from Taihu Lake by producing low-cost but high-quality BIOs.