Glycoside hydrolase production by Aspergillus terreus CM20 using mixture design approach for enhanced enzymatic saccharification of alkali pretreated paddy straw

518-524A successful lignocellulosic ethanol production process needs to address the technological impediments such as cost-competitiveness and sustainability of the process. Effective biomass utilization requires a repertoire of enzymes including various accessory enzymes. Developing an enzyme preparation with defined hydrolytic activities can circumvent the need for supplementing cellulases with accessory enzymes for enhanced hydrolysis. With this objective, mixture design approach was used in the present study to enhance glycoside hydrolase production of a fungal isolate, Aspergillus terreus CM20, by determining the proportion of different lignocellulosic components as enzyme inducers in the culture medium. A mixture of paddy straw and wheat straw (1.42:1.58) resulted in improved cellulolytic activities. The precipitated crude enzyme showed higher CMCase (365.03 18 IU g-1), FPase (161.48 IU g-1), avicelase (15.46 IU g-1), β-glucosidase (920.92 IU g-1) and xylanase (9627.79 IU g-1) activities. The potential of the crude enzyme for saccharification of alkali pretreated paddy straw was also tested. Under optimum conditions, saccharification released 25.0 g L-1 of fermentable sugars. This indicates the superiority of the crude enzyme produced with respect to its hydrolytic enzyme components

Prospecting cyanobacterial formulations as plant-growth-promoting agents for maize hybrids

Cyanobacteria represent environment-friendly inputs that can lead to savings of nitrogenous fertilisers, in addition to improving plant growth and soil fertility. The present investigation aimed to evaluate the potential of cyanobacteria inoculants as nutrient-management and plant-growth-promoting options for maize hybrids, which require high inputs of fertilisers. Four types of inoculants comprising consortia of cyanobacteria or cyanobacterium–bacterium and biofilmed preparations using Anabaena were evaluated for 11 maize hybrids. The microbial inoculants performed significantly better than the uninoculated control by bringing about 10–15% enhancement in Soil Plant Analysis Development (SPAD) value, plant height and available nitrogen (N) in the soil, which also led to a saving of 40 kg N ha−1. An additional enrichment of 40–50 kg N ha−1 in the soil was recorded in the treatments A1 (Anabaena–Providencia formulation) and A3 (Anabaena–Trichoderma biofilmed formulation). The cyanobacterial formulations A4 (Anabaena–Azotobacter biofilmed formulation) and A3 in conjunction with B10 (PMH-1), B8 (Bio-9681) and B9 (HM-8) proved to be superior associations. This is the first report on identification of promising cyanobacteria–maize genotype combinations as plant-growth-promoting and N-saving options. These results emphasise the significance of including cyanobacteria formulations in integrated nutrient management practices for this fertiliser-intensive crop.Keywords: biofertilisers, biofilms, cyanobacteria, maize, nutrient sequestratio

Prospecting plant growth promoting bacteria and cyanobacteria as options for enrichment of macro- and micronutrients in grains in rice–wheat cropping sequence

<div><p></p><p>The influence of plant growth promoting bacteria (PGPB) and cyanobacteria, alone and in combination, was investigated on micronutrient enrichment and yield in rice–wheat sequence, over a period of two years. Analysis of variance (ANOVA) in both crops indicated significant differences in soil dehydrogenase activity and micronutrient enrichment in grains (Fe, Zn in rice, and Cu, Mn in wheat). The combined inoculation of <i>Anabaena oscillarioides</i> CR3<i>, Brevundimonas diminuta</i> PR7, and <i>Ochrobactrum anthropi</i> PR10 (T6) significantly increased nitrogen, phosphorus, and potassium (NPK) content and improved rice yield by 21.2%, as compared to the application of recommended dose of NPK fertilizers (T2). The treatment T5 (<i>Providencia</i> sp. PR3 + <i>B. diminuta</i> PR7 + <i>O. anthropi</i> PR10) recorded an enhancement of 13–16% in Fe, Zn, Cu, and Mn concentrations, respectively, in rice grains. In wheat, <i>Providencia</i> sp<i>.</i> PW5 (T6) recorded the highest yield (5.23 Mg ha⁻¹) and significantly higher enrichment of Fe and Cu (44–45%) in the grains. This study highlighted the promise of combinations of cyanobacteria/bacteria and their synergistic action in biofortification and providing savings of 40–60 kg N ha⁻¹. Future focus needs to be towards integrating such promising environment-friendly and environmentally sustainable options in nutrient management strategies for this cropping sequence.</p></div