Evaluation of lignin waste as potential carriers for phosphate solubilizing bio-fertilizers: A zero waste technology

Purpose Incineration of plant biomass and refusing lignin rich effluent from paper industry to water bodies were seen as usual practice. This product-oriented research had a promising solution for recycling agro waste. Likewise, high quality handmade papers from dead-dry leaves of Ficus citrifolia, Swietenia mahagoni, Pinus roxburgii and Musa acuminate were obtained. Lignin was found to improve soil fertility and nutrient reservoir for microbial growth. So, this research managed and utilized lignin as liquid carriers to phosphate solubilizing bio-fertilizers (PSBs)- Meyerozyma gullerimondi and Providencia rettgeri.Method Handmade papers made were checked for quality by determining breaking length, burst factor, and gram per square meter (GSM). The essential nutrients in lignin waste were analyzed using FESEM-EDX (Field emission scanning electron microscope- energy dispersive X-ray spectroscopy). This confirmed suitability of lignin as fermenting carrier media for phosphate solubilizing biofertilizer (PSBs). After fermentation, nutrients were quantified using Carbon Hydrogen Nitrogen Sulphur (CHNS analyzer), Inductively Coupled Plasma- Atomic Emission Spectroscopy and Atomic Absorption Spectroscopy. The nutritional uptake studies of lignin PSBs were done on Vigna unguiculata (L) Walp.Results Musa acuminate produced handmade papers with the highest breaking length and burst factor (1160 m, 10.43 kg/cm2) followed by Ficus citrifolia (960 m, 7.2 kg/cm2), Swietenia mahagoni (480 m, 13.75 kg/cm2) and Pinus roxburgii (546 m, 4.0 kg/cm2) leaves. This lignin PSBs increased the growth of Vigna unguiculata (L) plant.Conclusion High quality handmade papers were made from waste leaves. The lignin spent from pulping industry could be utilized as carriers to phosphate solubilizers.