Sharma Sandeep, Kumawat Kailash Chand, Kaur Sukhjinder
Department of Soil Science, Punjab Agricultural University, Ludhiana, 141004, Punjab, India.
Environ Sci Pollut Res Int. 2022 Dec;29(58):88331-88346. doi: 10.1007/s11356-022-21809-3. Epub 2022 Jul 14.
Indigenous microbial diversity has potential for rapid decomposition of residue through enzyme activities that is alternative, effective, and environment friendly strategy to accelerate degradation of lignocellulose in agricultural residues and make composting process economically viable. Keeping this view, the main objective of the present study was isolation and characterization of lignocellulosic degrading microbial diversity from long-term residue management practice experiments and to develop potential microbial consortium for rapid degradation of lignocellulosic biomass. In this study, twenty-five bacteria, nine fungi, and four actinomycetes isolates were obtained from the soil samples of different residue management fields from Ludhiana, Punjab, India. All isolates were qualitatively and quantitatively screened for enzyme activities, i.e., cellulase, xylanase, laccase, and lignin peroxidase. On the basis of quantitative estimation of enzyme activities, 3 fungal (S1F1, S2F4, and S6F9), 2 actinomycetes (S1A1 and S6A4), and 2 bacterial strains (S6B16 and S6B17) were further selected for in vitro bio-compatibility assay. Selected bio-compatible microbial strains were identified as Streptomyces flavomacrosporus (S6A4), Aspergillus terreus (S2F4), and Bacillus altitudinis (S6B16) through 16S rRNA and 18S rRNA sequencing. Furthermore, single and developed microbial consortium (S6B16 + S6A4 + S2F4) were screened for quantitative estimation of cellulase, xylanase, laccase, and lignin peroxidase enzymes with 23 biochemically different cereal, legume, and oil seed crop residues for optimization of enzyme activities at different time intervals. Results revealed that Vigna radiata followed by Cajanus cajan and Arachis hypogaea straw residue powder @ 1% in culture broth are a promising carbon source for B. altitudinis, S. flavomacrosporus, and A. terreus to produce higher ligno-cellulolytic microbial degrading enzymes due to variable range of carbon (C):nitrogen (N) ratio and higher ligno-cellulolytic content in the studied crop residues. Thus, the application of indigenous microbial consortium with efficient lignocellulose hydrolysis enzyme machinery might be an attractive alternative for ex situ crop residue management practices under sustainable manners.
本地微生物多样性具有通过酶活性快速分解残留物的潜力，这是一种替代的、有效的且环境友好的策略，可加速农业残留物中木质纤维素的降解，并使堆肥过程在经济上可行。基于此观点，本研究的主要目的是从长期残留物管理实践实验中分离和表征木质纤维素降解微生物多样性，并开发用于快速降解木质纤维素生物质的潜在微生物群落。在本研究中，从印度旁遮普邦卢迪亚纳不同残留物管理田地的土壤样本中获得了25株细菌、9株真菌和4株放线菌分离株。对所有分离株进行了酶活性的定性和定量筛选，即纤维素酶、木聚糖酶、漆酶和木质素过氧化物酶。基于酶活性的定量估计，进一步选择了3株真菌（S1F1、S2F4和S6F9）、2株放线菌（S1A1和S6A4）和2株细菌菌株（S6B16和S6B17）进行体外生物相容性测定。通过16S rRNA和18S rRNA测序，将选定的生物相容性微生物菌株鉴定为大孢黄链霉菌（S6A4）、土曲霉（S2F4）和高地芽孢杆菌（S6B16）。此外，对单一和开发的微生物群落（S6B16 + S6A4 + S2F4）进行了纤维素酶、木聚糖酶、漆酶和木质素过氧化物酶的定量估计筛选，使用23种生化特性不同的谷物、豆类和油籽作物残留物，以优化不同时间间隔的酶活性。结果表明，在培养液中添加1%的绿豆秸秆残渣粉，其次是木豆和花生秸秆残渣粉，是高地芽孢杆菌、大孢黄链霉菌和土曲霉产生更高木质纤维素分解微生物降解酶的有前景的碳源，这是由于所研究作物残留物中碳（C）：氮（N）比范围可变且木质纤维素含量较高。因此，应用具有高效木质纤维素水解酶机制的本地微生物群落可能是以可持续方式进行异地作物残留物管理实践的有吸引力的替代方案。
