Development of rapid screening method for low-yielding chitosanase activity using Remazol Brilliant Blue-chitosan as substrate

Functional Properties of Chitosan Oligomers Obtained by Enzymatic Hydrolysis

The aims of this study were to obtain chitooligosaccharides (COS) from chitosan (CH) with improved functional properties and comparison of the use of two different enzymes: commercial cellulase (CL) and the dedicated enzyme chitosanase (CS). After enzymatic reaction, chitosan oligomers (NFs) were isolated by methanol into two fractions: precipitate (HMF) and supernatant (LMF). The occurrence of a hydrolysis reaction was confirmed by an increased reducing sugar content and viscosity reduction of chitosan oligomers. CPMAS 13C NMR analysis confirmed the dissimilar cleavage mechanism of the enzymes used. LMF and NF fractions were characterised by improved solubility in water (94.56%) compared to the HMF and CH samples (70.64%). Thermogravimetric analysis (TGA) showed that the HMF decomposed in two-stage process while CH, NF, and LMF decomposed in a three-stage process. The greatest mass loss of LMF samples (58.35%) suggests their sensitivity to high-temperature treatments. COS were a mixture of DP (degrees of polymerisation) from 3 to 18 hetero-chitooligomers, with an average Mw of <3 kDa. CL consisted of more low-DP products (DP 3-7) than COS made with CS. LMF characterised by DP~2 showed lower DPPH radical scavenging activity than HMF and NF with DP 3-7. The ability to reduce Escherichia coli increased in the given order: LMF > NF > HMF > CH.

Nutrient digestibility in black soldier fly larva was greater than in adults for pigs and could be estimated using fiber

The objectives of the present study were to determine the nutrient digestibility of fish meal, defatted black soldier fly larvae (BSFL), and adult flies and to develop equations for estimating in vitro nutrient digestibility of BSFL for pigs. in vitro digestion procedures were employed to mimic the digestion and absorption of nutrients in the pig intestine. Correlation coefficients between chemical composition and in vitro nutrient digestibility of BSFL were calculated. In Exp. 1, in vitro ileal digestibility (IVID) of dry matter (DM) and crude protein (CP) and in vitro total tract digestibility (IVTTD) of DM and organic matter in defatted BSFL meal were less (p < 0.05) than those in fish meal but were greater (p < 0.05) than those in adult flies. In Exp. 2, CP concentrations in BSFL were negatively correlated with ether extract (r = -0.91) concentration but positively correlated with acid detergent fiber (ADF; r = 0.98) and chitin (r = 0.95) concentrations. ADF and chitin concentrations in BSFL were negatively correlated with IVID of DM (r = -0.98 and -0.88) and IVTTD of DM (r = -1.00 and -0.94) and organic matter (r = -0.99 and -0.98). Prediction equations for in vitro nutrient digestibility of BSFL were developed: IVID of CP (%) = -0.95 × ADF (% DM) + 95 (r2 = 0.75 and p = 0.058) and IVTTD of DM (%) = -2.09 × ADF + 113 (r2 = 0.99 and p < 0.001). The present in vitro experiments suggest that defatted BSFL meal was less digestible than fish meal but was more digestible than adult flies, and nutrient digestibility of BSFL can be predicted using ADF as an independent variable.

Chitinolytic assay of indigenous Trichoderma isolates collected from different geographical locations of Chhattisgarh in Central India

Chitin is the second most abundant polymer in nature after cellulose and plays a major role in fungal cell walls. As a producer of variety of chitinase enzymes Trichoderma has become an important means of biological control of fungal diseases. A simple and sensitive method based on the use of basal medium with colloidal chitin as sole carbon source supplemented with Bromo cresol purple (pH indicator dye) is proposed to evaluate large populations of Trichoderma for chitinase activity. The soluble substrate with pH indicator dye (Bromo cresol purple, BCP) for the assay of chitinase activity on solid media is sensitive, easy, reproducible semi-quantitative enzyme diffusion plate assay and economic option to determine chitinases. Colloidal chitin derived from Rhizoctonia cell wall and commercial chitin included as a carbon source in broth also allowed selection and comparison of chitinolytic and exochitinase activity in Trichoderma spectrophotometrically. Released N-acetyl-β--D-glucosamine (NAGA) ranged from 37.67 to 174.33 mg/ml and 37.67 to 327.67 mg/ml and p-nitrophenol (pNP) ranged from 0.17 to 35.78 X 10(-3) U/ml and 0.62 to 32.6 X 10(-3) U/ml) respectively with Rhizoctonia cell wall and commercial chitin derived colloidal chitin supplemented broth.