Isolation and Screening of Microorganisms for the Effective Pretreatment of Lignocellulosic Agricultural Wastes

Abstract

Lignocellulosic waste is the most abundant biorenewable biomass on earth, and its hydrolysis releases highly valued reducing sugars. However, the presence of lignin in the biopolymeric structure makes it highly resistant to solubilization thereby hindering the hydrolysis of cellulose and hemicellulose. Microorganisms are known for their potential complex enzymes that play a dominant role in lignocellulose conversion. Therefore, the current study was designed to isolate and screen potential microorganisms for their selective delignification ability for the pretreatment of lignocellulosic biomass. An extensive isolation and screening procedure yielded 36 desired isolates (22 bacteria, 7 basidiomycete fungi, and 7 filamentous fungi). Submerged cultivation of these desired microorganisms revealed 4 bacteria and 10 fungi with potent lignocellulolytic enzyme activities. The potent isolates were identified as Pleurotus, Trichoderma, Talaromyces, Bacillus, and Chryseobacterium spp. confirmed by morphological and molecular identification. The efficiency of these strains was determined through enzyme activities, and the degraded substrates were analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). Among all isolated microbes, Pleurotus spp. were found to have high laccase activity. The cellulose-decomposing and selective delignification strains were subjected to solid-state fermentation (SSF). SSF of field waste corn stalks as a single-carbon source provides Pleurotus spp. better condition for the secretion of ligninolytic enzymes. These isolated ligninolytic enzymes producing microorganisms may be used for the effective pretreatment of lignocellulosic agricultural wastes for the production of high value-added natural products by fermentation.

Construction of cellulose-degrading microbial consortium and evaluation of their ability to degrade spent mushroom substrate

“…Additionally, in the XRD analysis results, the characteristic diffraction peak positions of F16 + F, PX1 + F7, and F7 + F8 are essentially identical to those of the RW, but with different intensities. This suggests that the ordered structure of the crystalline region in cellulose remained intact despite the colonization of the microbial consortium and enzyme contact ( Zhang et al, 2021 ). In the three groups of samples, the XRD diffraction peak positions did not change significantly, indicating that the microbial consortium cannot cause a significant change in the cellulose crystal structure of the SMS ( Luo et al, 2018 ).…”

Management of take-all disease caused by Gaeumannomyces graminis var. tritici in wheat through Bacillus subtilis strains

“…Bacterial strains JY122, JY214, ZY133, NW03, NO36, and JY215 were isolated for both cellulose and lignin degradation availability, from soil near wheat roots in different rural areas in Tangshan, Cangzhou, Daming, Zhengding, and Xingtang in Hebei province, China (Xiong et al, 2020 ; Zhang et al, 2021c ). Bacterial strains were cultivated in NB medium (10 g/L peptone, 5 g/L beef extract, and 10 g/L sodium chloride, pH 7.3) at 37°C, according to a published protocol (Tao et al, 2021 ), and Ggt was cultivated in PDA medium at a constant temperature of 26°C.…”

Isolation and Screening of Dye Degrading Lignocellulolytic Bacteria from Sundarban Mangrove Ecosystem, West Bengal, India

“…All isolates were qualitatively screened depending on the clear zone formation on the selective media supplemented with the suitable specific indicators (plate assay), indicating that isolates have ligninolytic, cellulolytic, and pectinolytic activity. 42 The highest zone-forming isolates were further studied (GD1, GD2, and GD3). Laccase-positive isolates were first identified in the LB-agar plate by oxidation of ABTS forming green color (Figure 2a) and also identified by the decolorization of malachite green and congo red in laccase selective plates 43 (Figure 2b, 2c).…”