Conversion of Lignocellulosic Wastes into Biofertilizer using Bacterial Consortium

Abstract

Lignocellulosic biomass abundantly and ubiquitously occupies the earth. However, their complex molecular structure prevents their use as a source of organic material for fermentable sugars and nutrients to be used as foods, fertilizers and biofuels. For an efficient carbon cycle, microbial enzymes play a key role in slow biodegradation of lignocellulosic wastes in nature. Microbiological applications can enhance the rate of biodegradation to utilize agro-industrial and organic municipal solid wastes, containing up to 50% lignocellulose substrates, as an inexpensive and sustainable source of plant nutrients. With this hypothesis, the current study was carried out to prepare a consortium of lignocellulose degrading bacteria and use it to convert lignocellulosic substrates in garden, sugarcane, rice, cotton and fruit waste into biofertilizer. Overall, 7-14% reduction in cellulose and 3-6% reduction in lignin content, along with decrease in pH was observed on treatment of above wastes with microbial consortium in 42 days. In spite of the low conversion rates observed in our study, better root, shoot as well as leaf development was observed in moong seedlings grown in soil amended with biofertilizer (3:1 ratio) as compared to controls. Another interesting observation was the biofertilizers with low pH prepared from sugarcane wastes (pH 3.1) and fruit wastes (pH 3.6) supported plant growth more efficiently as compared to other biofertilizers (pH 5.0 to 5.7). Thus, in addition to feasible conversion of lignocellulosic wastes into biofertilizer, our study further suggests the use of selective wastes as raw material depending on the preference of plants for slightly acidic to neutral soil pH for growth.