Table 1 The contributing factors for L. plantarum ATCC 8014 and S. marcescens B742 fermentation of shrimp shell powders (SSP). S. marcescens B742 fermentation 1 2 3 Lactobacillus plantarum ATCC 8014 fermentation 1 2 3 SSP (%) A 0.5 1.25 2 SSP (%) A 2 4 6 Contributing factors Sonication time Incubation (h) level (%) B C 1 5 1.5 10 2 15 Contributing factors Glucose Incubation concentration level (%) (%) B C 5 5 10 10 15 15 Culture time (day) D 2 3 4 Culture time (day) D 2 3 4 Table 2 DP (%) and DM (%) of shrimp shell powders after S. marcescens B742 fermentation and estimated parameters based on the orthogonal arrangement from the Taguchi design. Experimental run 1 2 3 4 5 6 7 8 9 Factors A Measured parameters DP (%) DM (%) b+ 28.59 12.33a 27.14b 17.36bc b 25.85 22.13d 29.15b 14.20ab b 30.88 33.73e b 30.53 18.68c 25.90b 33.81e a 20.17 15.68bc 15.74a 39.54f levels KA1 27.19ab++ 17.27a b KA2 30.19 22.20a KA3 20.60a 29.68a +++ Ri 9.59 12.41 a B KB1 27.88 20.11a a KB2 26.06 22.25a a KB3 24.04 26.78a Ri 3.84 6.67 a C KC1 26.43 15.56a KC2 24.01a 23.70a a KC3 27.54 29.89a Ri 3.53 14.33 D KD1 25.07a 28.53a KD2 27.85a 23.28a a KD3 25.06 17.33a Ri 2.80 11.20 Rank++++ A>B>C>D C>A>D>B + Means were not significantly different within nine treatments (P >0.05). ++ Means were not significantly different within individual factors (P >0.05). +++ Ri was the difference between the highest and lowest Kij values for each factor. ++++ Rank represented the order of Ri values. Kij was the average value of each measured functional parameter in level j (j=1, 2, 3) of each factor i (i=A, B, C, D) 28 DM (%) represented the efficacy of demineralization. DP (%) represented the efficacy of deproteinization. Table 3 Calcium content, DM (%), pH and total titratable acidity (TTA) of shrimp shell powders from L. plantarum ATCC 8014 fermentation and estimated parameters using the Orthogonal arrangement from the Taguchi design. Experimental run 1 2 3 4 5 6 7 8 9 Factors A Ca (mg/kg) 29.80a+ 22.91a 15.90a 65.24a 45.86a 65.30a 129.02ab 213.28b 128.20ab Measured parameters DM (%) pH 54.32abc 5.43d 49.39abc 3.71b a 38.04 3.26a bc 58.93 5.65d 53.37abc 4.64c c 65.93 5.49d 54.51abc 5.95de ab 42.59 6.22e 48.00abc 5.56d TTA (g/L) 0.17b 0.64e 0.67e 0.24cd 0.62e 0.20bc 0.26d 0.10a 0.27d levels KA1 22.87a++ 47.25a 4.13a 0.49a a a a KA2 58.80 59.41 5.26 0.35a KA3 156.83b 48.36a 5.91a 0.21a +++ Ri 133.96 12.16 1.78 0.28 a a a B KB1 74.69 55.92 5.67 0.22a a a a KB2 94.02 48.45 4.85 0.45a a a a KB3 69.80 50.66 4.77 0.38a Ri 24.22 7.47 0.90 0.23 a a a C KC1 102.79 54.28 5.71 0.16a KC2 72.115a 52.11a 4.97a 0.38a a a a KC3 63.59 48.64 4.62 0.52a Ri 39.20 5.64 1.09 0.36 a a a D KD1 67.95 51.89 5.21 0.35a KD2 72.41a 56.61a 5.05a 0.37a a a a KD3 98.14 46.52 5.04 0.34a Ri 30.19 10.09 0.167 0.03 Rank++++ A>C>D>B A>D>B>C A>C>B>D C>A>B>D + Means were not significantly different within nine treatments (P >0.05). ++ Means were not significantly different within individual factors (P >0.05). +++ Ri was the difference between the highest and lowest values. ++++ Rank represented the order of Ri values. Kij was the average value of each measured functional parameter in level j (j=1, 2, 3) of each factor i (i=A, B, C, D) 28 DM (%) represented the efficacy of demineralization. Table 4 Major chemical parameters of shrimp shell powders after one-step fermentation under optimal fermentation conditions and successive two-step fermentation. Culture time (Day) Detecting parameters S. marcescens B742 fermentation Ca (mg/kg) DP (%) 1 0.575±0.16 1784.69 ± 15.13d 58.14a c 2 0.593±0.16 1701.16 ± 17.47 64.21b 3 0.627±0.08 1483.51 ± 12.65b 76.53c a 4 0.625±0.13 1363.77 ± 9.78 83.37d 5 0.625±0.10 1308.11 ± 8.16a 83.44d L. plantarum ATCC 8014 fermentation Ca (mg/kg) DP (%) 1 0.610±0.04 181.74±10.09b 48.40a 2 0.530±0.11 157.15±12.37a 60.97b a 3 0.553±0.01 155.24±9.34 61.42b 4 0.597±0.61 154.09±8.37a 62.53b a 5 0.570±0.04 147.12±10.07 63.33b Successive two-step fermentation Ca (mg/kg) DM (%) DP (%) Chitin yield (%) A 0.504±0.14 54.36±3.21 94.48 92.99 18.90 B 2.037±0.35 2230.46±15.36 ------DM (%) represented the efficacy of demineralization. DP (%) represented the efficacy of deproteinization. SSP: Shrimp shell powders. A: successive two-step fermentation; B: SSP (control group). SSP Weight (g) DM (%) 41.37a 52.59b 54.45b 51.83c 54.31d DM (%) 61.15b 85.28a 86.10a 86.28a 86.50a Chitin recovery (%) 75.80 --- Table 5 DA and crystallinity index of commercial chitin, chitin obtained by S. marascens B742 fermentation, by L. plantarum ATCC 8014 fermentation and by successive two-step fermentation. Samples Commercial chitin Chitin obtained by S. marascens B742 fermentation Chitin obtained by L. plantarum ATCC 8014 fermentation Chitin obtained by successive two-step fermentation DA: degree of acetylation. Data were mean of three replications. DA (%) 87.64 ± 1.31 25.33 ± 2.36 83.09 ± 7.38 Crystallinity index (%) 98.58 ± 0.29 80.04 ± 1.69 92.15 ± 0.35 80.17 ± 5.24 79.23 ± 2.31