Optimizing Bacillus circulans Xue-113168 for biofertilizer production and its effects on crops

In this study, Bacillus circulans Xue-113168 biofertilizer was produced through solid state fermentation processes using food waste and feldspar. Results confirmed that solid state fermentation has considerable advantages compared to complex process (solid-state and bio-bleach). The control of pH, temperature, and humidity effectively led to the formation of 2×109 cfu/g spore and dissolution of potassium at a rate of 41.53%. Compound microbial fertilizer (CMF), formulated by humic acid and K2HPO4 with biofertilizer, has a quick and durable effect. CMF increases the yield of rapeseeds by 75 to 89%, provides higher vitamin C and reduces nitrate in leaf. Yields of selenium-enriched jujube and jujube increased, respectively, in the CMF compared to the matrix control; rates of anthracnose and rust diseases also decreased. Furthermore, our results showed that CMF improved soil properties, such as organic matter, NPK content from 8.83 to 16.16 kg hm2, and reduced chemical fertilizer from 25 to 11%, respectively. For convenient medium, robust process and good effect, CMF is suitable for potassium deficiency and undeveloped arable land resources.   Key words: compound microbial fertilizer, Bacillus circulans Xue-113168, solid-state fermentation (SSF), process, optimize.