ABSTRACT This research aims to evaluate the effect of molasses as a source of organic carbon on the growth and lipid profile of Dunaliella salina cultivated under different light regimes to determine its strategy and potential use to produce biodiesel. Two sources of nutrients (F/2 medium, F/2; molasses, M) and two light conditions (12 h light: 12 h darkness, 12L:12D) conformed four treatments (F/2 12L:12D, F/2 D, M 12L:12D, and MD) that were investigated with three replicates each. The concentration of microalgae produced by the groups under light conditions was more than double that of those grown in darkness. The highest biomass produced (46.91 ± 6.47 g L-1) was obtained in the F/2 medium with 12L:12D treatment, while the lowest (18.99 ± 0.78 g L-1) was in the M 12L:12D group. Regardless of the culture conditions, the lipids were mainly composed of the C16:0 and C18 fatty acids. The use of molasses as a culture medium produced the highest amount of C18:1, regardless of the light regime. Molasses promoted the highest production of fatty acids methyl esters. Depending on the culture medium, D. salina cells showed different percentages of saturated (SFA), monounsaturated (MFA), and polyunsaturated (PUFA) fatty acids. The highest amount of saturated fatty acids was obtained in F/2 12L:12D. The highest amount of polyunsaturated fatty acids was presented in the mixotrophic culture (molasses and light). The cultures grown with molasses were rich in monounsaturated fatty acids. An inexpensive industrial by-product, Cane molasses could be a low-cost feedstock for biodiesel in cultivating D. salina.

RESUMO: Dois tratamentos químicos, cinco enzimáticos (pectinase, lipase, hemicelulase, hemicelulose-celulase ou lipase-pectinase) e um microbiológico (Bacillus subtilis) foram avaliados para obter o cloridrato de glucosamina (Gluc-HCl) da quitina obtida a partir de exoesqueletos de caranguejo (Callinectes. Bellicosus). Os dois tratamentos químicos foram nomeados como método A (hidrólise de HCl para 75 min a 90 °C) e método B (hidrólise de HCl para 20 min e 14 h de repouso). A Glucosamina e, em alguns casos, N-acetil-D-glucosamina foram identificados e quantificados por HPLC. Os tratamentos em que as melhores concentrações de Glucosamina-HCl foram obtidas, em ordem decrescente: lipase (94,4 mg/g), microbiológica (45,7 mg/g), lipase-pectinase (22,9 mg/g), hemicelulase-celulase (20,9 mg/g), hemicelulase (15,3 mg/g), pectinase (10,7mg/g), Quïmica A (7,3 mg/g) e Quïmica B (7,3 mg/g). Em termos de produtividade, os melhores tratamentos em ordem decrescente foram: pectinase (94%), microbiológica (94%), hemicelulase (92%), lipase (91%), química B (88%), lipase-pectinase (88%), hemicelulase- celulase (86%) e produto químico A (28,5%). Os dois melhores tratamentos foram lipase e microbiológicos, propostos como método viável para obtenção de Gluc-HCl a partir de exoesqueletos de caranguejo; cumprem procedimentos ecologicamente corretos e podem agregar valor à cadeia produtiva do caranguejo.

ABSTRACT: Two chemical treatments, five enzymatic (pectinase, lipase, hemicellulase, hemicellulose-cellulase or lipase-pectinase) and one microbiological (Bacillus subtilis) treatment were evaluated to obtain glucosamine hydrochloride (Gluc-HCl) from the chitin obtained from crab (Callinectes bellicosus) exoskeletons. Chemical treatments were referred as Method A (HCl hydrolysis during 75 min at 90°C) and Method B (HCl hydrolysis during 20 min and 14 h of rest). Glucosamine and, in some cases, N-acetyl-D-glucosamine were identified and quantified by HPLC. Treatments with the greater concentrations of Gluc-HCl in descending order were: lipase (94.4 mg/g), microbiological (45.7 mg/g), lipase-pectinase (22.9 mg/g), hemicellulase-cellulase (20.9 mg/g), hemicellulase (15.3 mg/g), pectinase (10.7 mg/g), Chemical A (7.3mg/g) and Chemical B (7.3mg/g). In terms of yield, the best treatments in descending order were: pectinase (94%), microbiological (94%), hemicellulase (92%), lipase (91%), Chemical B (88%), lipase-pectinase (88%), hemicellulase-cellulase (86%) and Chemical A (28.5%). The two most profound treatments were lipase and microbiological, so they are proposed as part of a viable method to produce Gluc-HCl from crab exoskeletons; they are ecofriendly procedures and could add value to the crab´s productive chain.

ABSTRACT The effects of reducing feeding rate and molasses on water quality, growth, and gene expression of Litopenaeus vannamei were evaluated in a super intensive system with zero water exchange. A bioassay of 35 days (0,75 ± 0,22 g, 36 shrimp tank-1, 450 shrimp m-3) with treatments in triplicate was performed: I) 100% commercial feed (control group) with water exchange; II) 100% commercial feed without water exchange; III) 100% commercial feed + Bacillus licheniformis BCR 4-3 + molasses without water exchange; IV) 90% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange, and V) 80% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange. Shrimp survival, weight, nitrogenous wastes, settleable solids (SS), and the relative expression (RT-qPCR) of stress and digestive genes were determined. Shrimp survival was 100% in all treatments. The reduced diet, bioflocs, and bacilli did not affect shrimp growth. The culture conditions reduced nitrogenous wastes and modulated mRNA expression of trypsin, chymotrypsin, and heat shock protein 70. Reduced feed ration can help to maintain water quality and lower costs in intensive shrimp cultures with bioflocs.