Production Biotechnology with Controlled Environmental Regimes, Substrates and Enzyme Markers for the Shiitake Mushroom, Lentinula Edodes

Mycelial growth of L. edodes was optimum at 25°C in six of the seven strains of L. edodes tested. Mycelial biomass production was greater on sawdust than grain with 0.53 to 1.60 mg glucosamine per 200 g substrate derived from sawdust compared to 0.02 to 0.2 mg glucosamine per 200 g from grain. In fructification, a fluctuating temperature set of 15°C (8 h)/25°C (16 h), with continuous lighting at 25- 35 lux, humidity of 80-95% and aeration of 1.3-2.5 m/s produced the highest yield or Biological Efficiency (RE.) in 11 of the 13 strains tested at three temperature sets. Strains L38 (7.1-32.7% B.E.) and L300 (7.2-35.5% RE.) were the best yield producers at all three temperature sets. Mycelial density during spawn-run was found to be uncorrelated with yield in the 13 strains tested. In the present study, specific activities of three lignocellulolytic enzymes, laccase, carboxymethylcellulase (CMC'ase) and xylanase indicated that the second week and 17th week· was the correct time to initiate fruiting on liquid and rubber sawdust medium respectively

Azospirillum Genomes Reveal Transition of Bacteria from Aquatic to Terrestrial Environments

Fossil records indicate that life appeared in marine environments ∼3.5 billion years ago (Gyr) and transitioned to terrestrial ecosystems nearly 2.5 Gyr. Sequence analysis suggests that “hydrobacteria” and “terrabacteria” might have diverged as early as 3 Gyr. Bacteria of the genus Azospirillum are associated with roots of terrestrial plants; however, virtually all their close relatives are aquatic. We obtained genome sequences of two Azospirillum species and analyzed their gene origins. While most Azospirillum house-keeping genes have orthologs in its close aquatic relatives, this lineage has obtained nearly half of its genome from terrestrial organisms. The majority of genes encoding functions critical for association with plants are among horizontally transferred genes. Our results show that transition of some aquatic bacteria to terrestrial habitats occurred much later than the suggested initial divergence of hydro- and terrabacterial clades. The birth of the genus Azospirillum approximately coincided with the emergence of vascular plants on land

Field monitoring of plant-growth-promoting rhizobacteria by colony immunoblotting

Inoculant plant-growth-promoting bacteria are emerging as an important component of sustainable agriculture. There is a need to develop inexpensive methods for enumerating these organisms after their application in the field, to better understand their survival and impacts on yields. Immunoblotting is one potential method to measure viable cells, but the high cost of the conventionally used nylon membranes makes this method prohibitive. In this study, less expensive alternative materials such as filter papers, glossy photo papers, and transparencies for the purpose of colony immunoblotting were evaluated and the best substance was chosen for further studies. Whatman filter paper No. 541 combined with a 0.01 mol.L⁻¹ H₂2SO₄ rinsing step gave similar results to nylon membranes but 10⁷ CFU.g⁻¹) of the plant-growth-promoting bacteria 'Pseudomonas fluorescens', 'Azospirillum brasilense', or 'Rhizobium leguminosarum'. The modified protocol allowed the identification and recovery of over 50% of the inoculated cells of all three strains, amidst a background of the native soil microflora. Subsequently, the survival of 'P. fluorescens' was successfully monitored for several months after application to field-grown rice at Jerilderie, New South Wales, Australia, thus validating the procedure