High Throughput Screening Technologies in Biomass Characterization

Biomass analysis is a slow and tedious process and not solely due to the long generation time for most plant species. Screening large numbers of plant variants for various geno-, pheno-, and chemo-types, whether naturally occurring or engineered in the lab, has multiple challenges. Plant cell walls are complex, heterogeneous networks that are difficult to deconstruct and analyze. Macroheterogeneity from tissue types, age, and environmental factors makes representative sampling a challenge and natural variability generates a significant range in data. Using high throughput (HTP) methodologies allows for large sample sets and replicates to be examined, narrowing in on more precise data for various analyses. This review provides a comprehensive survey of high throughput screening as applied to biomass characterization, from compositional analysis of cell walls by NIR, NMR, mass spectrometry, and wet chemistry to functional screening of changes in recalcitrance via HTP thermochemical pretreatment coupled to enzyme hydrolysis and microscale fermentation. The advancements and development of most high-throughput methods have been achieved through utilization of state-of-the art equipment and robotics, rapid detection methods, as well as reduction in sample size and preparation procedures. The computational analysis of the large amount of data generated using high throughput analytical techniques has recently become more sophisticated, faster and economically viable, enabling a more comprehensive understanding of biomass genomics, structure, composition, and properties. Therefore, methodology for analyzing large datasets generated by the various analytical techniques is also covered

Regulation of aspartokinase in Lactobacillus plantarum

6 pages, 3 figures, 2 tables.As a rational approach to the genetic development of a stable lysine overproducing strain of Lactobacillus plantarum for the fermentation of 'ogi', a Nigerian fermented cereal porridge, regulation of lysine biosynthesis in this species was investigated. Spontaneous lysine overproducing mutants of Lact. plantarum were obtained and their aspartokinase activities compared with those of wild-type strains under different conditions. Results showed that aspartokinase activity of Lact. plantarum cell extracts was not inhibited by either lysine, threonine, methionine or combinations of lysine and threonine. Instead, methionine enhanced aspartokinase activity in vitro. Results indicated that lysine biosynthesis in Lact. plantarum could be regulated by lysine via the control of aspartokinase production in a way different to that described for other bacteria.This work was financed by a grant from the Project 6 ACP UNI 032 Training Programme of the European Commission awarded to OOA. JLR-B was the recipient of a grant from the European Commission (Project BIOT-CT91-0263).Peer reviewe