Crop residue degradation by fungi isolated from conservation agriculture fields under rice–wheat system of North-West India

Abstract

Purpose In North West-Indo Gangetic Plains (NW-IGP) of India in situ burning of crop residues is practiced by majority of farmers' which deteriorates soil and environmental quality. Fungi have the potential for lignocellulose degradation and can be used for the in situ decomposition of crop residues. Lignocellulose degrading fungal spp. were isolated and evaluated for the activity of lignocellulolytic enzymes. Method The lignocellulose degrading fungi were isolated by appearance of zone on carboxy methyl cellulose (CMC) agar media and tannic acid (TA) media. Carboxy methyl cellulase, filter paperase, cellobiase, xylanase and laccase activity were estimated in submerged, as well as solid state fermentation using a mixture of rice and wheat straw in the ratio of 4:1. rice-wheat straw as substrate. The residue left after solid state fermentation was evaluated for carbon/nitrogen ratio, dry mass loss, and loss of cellulose, hemicellulose and lignin. Selected potential isolates were further tested in pot experiment for their effect on wheat plants. The interaction among isolates was also studied. Result After primary screening, 19 out of a total of 72 fungal isolates were selected based on their enzymatic activity profile and potential to degrade lignocellulosic residues in submerged fermentation. Out of these 19 isolates, 11 were further selected based on their enzymatic secretions in solid state fermentation. All the 11 strains were identified morphologically. Four fungal isolates (RPW 1/3, RPW 1/6, RPWM 2/2 and RZWM 3/2) showed higher enzymatic activities and more loss of dry mass and cell wall constituents over the other isolates. These isolates were identified by ITS region sequencing as Aspergillus flavus, Aspergillus terreus, Penicillium pinophilum and Alternaria alternata. Conclusion This study revealed that fungal isolates may be used for managing crop residues in conservation agriculture based rice-wheat system of NW-IGP to eliminate ill effects of residue burning.

Soil biological properties and fungal diversity under conservation agriculture in Indo-Gangetic Plains of India

“…Microbial enzymes are involved in soil nutrient cycling, and are used to evaluate soil quality (Choudhary et al, 2018). Among soil microbes, fungi are critical components in soil system and are regarded as the primary decomposers in soils, as they secrete various enzymes that breakdown lignocelluloses (Choudhary et al, 2016).…”

Utilization of wheat straw for fungal phytase production

“…(Bhavsar et al 2011;Moreira et al 2014), Mucor racemosus (Bogar et al 2003b), and Sporotrichum thermophile (Singh andSatyanarayana 2006b, Maurya et al 2017), Thermomyces lanuginosus (Makolomakwa et al 2017), and Rhizopus oryzae (Arora et al 2017) have been reported to produce phytase. Several filamentous fungi and their enzyme products are used to break down the bond between the polysaccharides (cellulose and hemicellulose) and lignin in wheat straw to improve its digestibility through the process referred to as biological-pretreatment (Sindhu et al 2016, Choudhary et al 2016, Bagewadi et al 2017. Many previous studies have also reported the ability of filamentous fungi to produce various commercial enzymes from wheat straw (Table 1).…”

Exploring functional fungi on organic matter decomposition of oil palm empty bunches as bio-resource in land remediation

“…Cultured selected isolates in three types of medium were shown a growth rate in decomposed material faster than empty bunches. The effectiveness of biodegradation of lignocellulolytic microbes in different media has been reported in some research such as the activity of cellulase in liquid medium using wheat bran as carbon source (Sorgatto et al 2012), lignocellulolytic activity in solid-state fermentation (Choudhary et al 2016). In the case of oil palm empty fruit bunch decomposition, Shahriarinour et al (2011) reported the effect of different fermentation substrates in the activity of Aspergillus terreus.…”