The effect of storage on yield and modification of starch using hydrochloric acid and acetic anhydride were studied. Yield of starch from fresh roots (24.4%) was significantly greater than yield (16,2%) from roots stored at room temperature for six days. On a dry weight basis the amount of starch in the roots decreased over a six day storage period. The proximate composition of cassava starch on dry weight basis was 0.24% ash, 0.13% fat, 0.49% protein, 0.15% crude fibre and 98.4% starch. The isolated starch was treated with different concentration of hydrochloric acid to produce acid thinned and dextrinized starches and different concentration of acetic anhydride to produce acetyl substituted starches. The alkali number of acid thinned and dextrinized starches increased with acid treatment while the viscosity decreased. The degree of substitution increased with the concentration of acetic anhydride used. The cold water solubility of the acid thinned and acetyl substituted starches were similar to that of native starches while the solubility of the dextrinized starches increased with the acid concentration. The viscosity of the acetyl substituted starches increased with the degree of substitution.

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.

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Physicochemical and functional properties of low degree of substitution (DS) cassava starch citrates and acetates were compared with properties of native cassava starch. Substituted starches have lower ash content and pH, but the solubility in water at room temperature was not significantly different from that of the native starch. Swelling power of the substituted starches was dependent on the extent of substitution. Apparent viscosities were generally lower in starch acetates and citrates than the native starch. The substituted starches had better cooking properties in terms of lower setback viscosity, reduced gelatinization time and better stability at low pHs. Substituted starches also have better colour, improved freeze‐thaw stability and better storage characteristics at room temperature compared to native starch.

Lipases (EC 3.1.1.3, glycerol ester hydrolase) cat-alyze the hydrolysis of triacylglycerols to glycerol and free fatty acids. Recently, a variety of new applications of lipase have emerged, especially in enantioselective hydrolysis of esters (Nakano et al. in modification of sugars or chiral drugs (Bornemann et al., 1992; Margolin, 1993; Patil et al., 1991). Many different kinds of microbial lipases have been reported, and they have received much attention because of their potential use in industry (Björkling et al., 1991; Har-wood, 1989). However, the known lipases scarcely hy-drolyze esters containing a bulky alcohol moiety, such as tertiary-alcohol esters, although primary-alcohol es-ters (Amaya et al., 1995; Linko et al., 1995; Zaidi et al., 1995) and secondary-alcohol esters (Iwai et al., 1980; Mitsuda et al., 1988) are good substrates for li-pases. This lack of ability to hydrolyze bulky alcohol esters hindered the wide use of lipases for complex compounds. Therefore, we started to obtain a lipase that hydrolyzes t-butyl octanoate (TBO) as a model substrate for bulky esters, and isolated a microorganism that produces a new type lipase from soil samples. In this report, we describe the primary characterization of this lipase and taxonomic identification of the producer. Materials and Methods Preparation of t-butyl esters. The t-butyl alcohol esters used in this work were prepared from t-butyl alcohol and corresponding acid chlorides. The typical protocol for the synthesis of TBO is described below. Octanoyl chloride (48 g, 0.3 M) was added dropwise to a mixture of 2-methyl-2-propanol (80 g, 1.08 M), anhy-drous pyridine (25.6 g, 0.32 M), and 4-dimethyl aminopyridine (1 g, 8.2 mM) in 800 ml of hexane at 0-5°C for 2 h. After 14 h reaction at room temperature, water (400 ml) was added to the mixture and the hexane layer was separated. The hexane solution was washed with water, 1 N HCl solution and sodium carbonate solution. The hexane layer was separated, washed with water, dried over sodium sulfate and concentrated under reduced pressure to yield 39.3 g (65.5%) of oil. The structure was confirmed by 1 H-NMR and IR spectroscopy. Other t-butyl esters were Fatty acid esters composed of sterically hindered alcohol are very poor substrates for known li-pases. In order to obtain a novel lipase, t-butyl octanoate (TBO) was selected as a model substrate to screen for bacteria-producing lipase(s) which can preferentially hydrolyze bulky esters. Of 279 strains isolated from 350 soil samples based on the ability to grow with TBO as a sole carbon source, one strain (YY62) was chosen for its strong TBO-hydrolyzing activity. Strain YY62 is a Gram-negative motile rod and was identified as Burkholderia sp. from the taxonomic characters and phylogenetic analysis of 16S rDNA nucleotide sequences. Using the activity ratio between TBO and p-nitrophenyl acetate as a measure for preference to bulky esters, we confirmed that the lipase of strain YY62 was 100-fold superior to commercial lipases in terms of TBO-hydrolyzing activity.